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Help Needed - Cooling System problems

markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
Let me start this with a quick problem statement:

I have changed almost every component in my cooling system over the last year and the car is running hotter than ever. I need help figuring out why because I think I've done all the obvious things and none seem to be working.

Some background facts:

• My car is a 1971 with the 10.5:1 engine. I run a Holly 650 and use 94 octane fuel (usually with a Race formula octane boost). The car currently has about 18,000 miles on it. Timing is set to 6° BTDC as per specs. I use a Duraspark II ignition system. Overall the engine runs great and even gets 20 MPG on the highway.

Temp Gauge

• When I got my car it didn't run exceptionally hot except (typically the Gauge indicated 185°) the very odd time when I got stuck in summer rush-hour for almost an hour (Gauge indicated 230°)

• I accept that the gauges don't indicate accurate temps, but I make the assumption (yeah, I know) that it is functioning consistently and the numbers, while wrong, are relatively correct — at least as far as relative temperature changes goes.

• After a couple of years of driving, the car gradually indicated it was running hotter and when doing so, I noticed an increasing in pinging.

• I replaced the water pump with the recommended Edelbrock unit. No change in running temps was experienced afterwards, and I am convinced my original pump was functioning perfectly.

• After another year I noticed some mild weeping of coolant at the rear of the head gaskets (usually after the car sat for a month of storage) and so I decided to replace the head gaskets. I used high-quality FelPro blue gaskets and believe they were installed correctly. The heads had a cleaning pass done on them to ensure they were flat and I was told it was a very minimal shave that shouldn't increase compression any significant amount. After all was completed, still the car ran hot.

• A month ago I decided enough was enough and I changed the rad to a new Fluidyne unit (with new senders) and installed new Flex-a-lite dual sucker fans, new stainless cooling pipes and new hoses. The morning after I completed the install, I headed off to Montreal. I drove well above the posted limit (maybe) and the car ran an indicated 165° all the way there. I was ecstatic. UNTIL we hit downtown traffic and the car started to heat up. With both fans on the temp stayed between 200 and 220 (between the tick in the middle of 160 and 230 on the gauge). The fans definitely move a LOT more air and the air coming through the rad is definitely hot (when the gauge shows hot). One fan is on the low-temp rad sensor and the other is switched at the dash (typical for '71 cars).

Rad and fans

• A couple of hoses had loosened up overnight while in Montreal and so a cup or so of coolant leaked out from the bottom tubes. I just topped up the pressure tank with coolant and headed home. It was a warmer day but the car did run a lot hotter - indicated about 200° compared to the previous day's 165°.

• Upon returning, I decided the only thing left to change was the thermostat. I had ordered a couple Robert Shaw units and they didn't arrive in time. With the new 333-180 stat, I again drained buckets of coolant, removed the old stat (a 160° unit of unknown origin) and installed the RS unit. I again bled the system but for some reason wasn't able to put back as much as I had drained out (at least I think that was the case unless I mixed up my jugs of coolant). I has a cup or two coolant left over.

Thermostat

• my normal process for bleeding the system is: start with cold car, back end raised about a foot, inside heater lever to hot, bleed screw on rad open and fill coolant through the pressure tank until it comes out the rad while running the engine. Run the engine until coolant in the pressure tank starts to bubble, cap the tank and shut off the engine. BUT, when I did this I forgot to add coolant to about half-way on the overflow tank the first time, so I'm sure it sucked air into the system.

• I have also seen coolant leaking out from the pressure cap so I decided to replace it. I'm pretty sure my tanks have been modified because they have the nice billet caps with the pressure cap bonded it. When I removed it, the number on it is RC82 which is a GM rad cap part number. I bought a new Prestone branded cap (see cap on right)

Photobucket

The original cap on my tanks:

Pressure Cap

• I have tried burping the system and raised the front of the car to see if I can get any more air out of the rad (not a bubble).

I have tried not to leave out any details and I really appreciate any suggestions as to what is going wrong here. I THINK it's air trapped, but I have never had this much trouble getting air out before, so I'm not sure. This was the longest time the car sat (over a month) with no coolant in it while I replaced everything (I re-carpeted front trunk, repainted front rad area etc.) but even so, this is stumping me.

Thanks for any ideas.

Mark
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George PGeorge PAdmin.
Remove the cap from the swirl tank, raise the rear of the car, fill the swirl tank and the recovery tank, start the motor and let it idle, keep adding coolant to the swirl tank as long as you can. When the swirl tank begins to overflow with hot coolant spilling out (indicating the thermostat has opened) twist the cap back on the the swirl tank. Let it run another 5 minutes & shut the motor off. Drop the rear end of the car. You've hopefully burped all the air from the radiator and under-car tubes but there is most likely air trapped in the highest point of the motor, i.e. the rear of the cylinder heads.

Let the engine cool enough that you feel safe to remove the swirl tank cap again. After removing the cap raise the front of the car. Start the motor and let it idle, add coolant to the swirl tank if you can. When the swirl tank begins to overflow with hot coolant spilling out (the thermostat has opened again) twist the cap back on the the swirl tank. Let it run another 5 minutes & shut the motor off. Drop the front of the car. Hopefully any air trapped in the cylinder heads has been burped.

Theoretically you've burped all the air from the system. If the car still runs hot, run through the procedure one more time.

All this "burping" is necessary because the Pantera vent system doesn't function at all. If you perform the vent system modifications I've detailed in the sticky you won't have to do all this "burping".

-G
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
Thanks guys.

Any thought on if the old pressure cap shown above IS in fact a GM part? How can I tell if my car has the replacement US style neck (as I suspect). I want to eliminate a leaky cap but not by replacing it with an incorrect unit.

Also, when my car warms up, the coolant level in the swirl tank slowly rises. It isn't more than 1/2" from the top (where the rubber seals it) when the car is cold so it overflows fairly soon (5 min?). Should I start with a lower level? My overflow tank is full now, judging by how often it is puking coolant when the engine gets hot.

How high should the ends be raised when doing this. I have them about a foot. Is that too high?

I will try the "burping" again. I did read the excellent sticky you wrote George (thanks for doing that for us!) and I plan to do that mod as soon as I can.

Thanks,

Mark
lf-tp2511lf-tp2511Member
Mark,

Do keep in mind that while your temps are higher than in the past, your car is not showing any signs of overheating.

You make no mention of it puking when parked after a long run, or of hearing funny boiling sounds coming from the engine or tanks.

Remember the Ford 'fix' for the multitude of owners that saw high gauge temperatures as a problem was to add a resistor to the gauge wiring, which kept the needle at a lower point. It made no difference to the water temperature, but it allowed the owners to relax and enjoy the ride. Too many owners were used to just idiot lights and actually seeing the temperature freaked them out.

New cars run as hot as yours by design.

Last thought, timing can directly affect an engine's temperature. Has your been worked on, or checked?

Larry
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
quote:
Originally posted by LF - TP 2511:
Do keep in mind that while your temps are higher than in the past, your car is not showing any signs of overheating.

You make no mention of it puking when parked after a long run, or of hearing funny boiling sounds coming from the engine or tanks.


Well, actually, it is — at least I think so. When it gets very hot and starts pinging a LOT more than it used to. I mention above but not in my original post that it is puking coolant out the overflow when it is running (and is overheating). Additionally, when I shut the engine down, I hear gurgling at the front of the engine (I have the covers off now, so maybe that is normal and I just don't normally hear it).

quote:
Remember the Ford 'fix' for the multitude of owners that saw high gauge temperatures as a problem was to add a resistor to the gauge wiring, which kept the needle at a lower point. It made no difference to the water temperature, but it allowed the owners to relax and enjoy the ride. Too many owners were used to just idiot lights and actually seeing the temperature freaked them out.


All agreed, but again, mine USED to not overheat. Yes, I'm freaking out, but principally because I am about to head off to drive my car in the mountains for two weeks. Altitude and overheating engines are not the best combination if memory serves me correctly.

quote:
Last thought, timing can directly affect an engine's temperature. Has your been worked on, or checked?


Yes, in fact that was one of the first things I checked. It's set at 6° as per specs. The advance appears to be working properly (I checked it using the factory manual method).

Keep 'em coming!

Mark
J jb1490Member
Mark,

Have you checked for timing chain stretch? If you have the original timing chain and sprockets, then you will have considerable chain stretch and sprocket wear (original cam sprocket has nylon teeth).

The sending unit for the temp gauge (or the gauge) could be "deteriorating" with age, giving an incorrect reading.

Have you used an IR temp gun to check temps when the cooling system is indicating "high" temps?

The distance from the bottom seat of the swirl tank's filler neck to the top of the neck (sealing surface to sealing surface) on my SS tank measures .760", and on my original tank it measures .770".

The swirl tank should always be full (hot or cold) to the top (lower sealing surface), and the overflow tank should be about half full. As the coolant heats up, expands, and builds up pressure, it will force some of the coolant into the overflow tank. This is normal. As the coolant cools, whatever coolant that the swirl tank needs will automatically be drawn back into it (the swirl tank). If the overflow tank is too full, then any excess coolant will be pushed out of the overflow tank (via the tube) and onto the ground (and probably on the car).

Did you retorque the heads after installing the new head gaskets (after the engine was run)?

John
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
quote:
Originally posted by jb1490:
Have you checked for timing chain stretch? If you have the original timing chain and sprockets, then you will have considerable chain stretch and sprocket wear (original cam sprocket has nylon teeth).


No, I haven't thought of that. With only 18,000 miles I hoped it wouldn't be an issue. The inside of the engine looked like new. In fact you can still see the original honing marks in the cylinders. No wear ridges by the pistons, no gunk collected anywhere.

quote:
The sending unit for the temp gauge (or the gauge) could be "deteriorating" with age, giving an incorrect reading.


I might change that just to be safe, but the engine "feels" like it's running hot (pinging too...).

quote:
Have you used an IR temp gun to check temps when the cooling system is indicating "high" temps?


No, but I can. Where should I measure those temps and what numbers should I expect of a normal engine temp?

quote:
The distance from the bottom seat of the swirl tank's filler neck to the top of the neck (sealing surface to sealing surface) on my SS tank measures .760", and on my original tank it measures .770".


Thanks, I'll measure those tonight.

quote:
The swirl tank should always be full (hot or cold) to the top (lower sealing surface), and the overflow tank should be about half full. As the coolant heats up, expands, and builds up pressure, it will force some of the coolant into the overflow tank. This is normal. As the coolant cools, whatever coolant that the swirl tank needs will automatically be drawn back into it (the swirl tank). If the overflow tank is too full, then any excess coolant will be pushed out of the overflow tank (via the tube) and onto the ground (and probably on the car).


Clearly my overflow tank is too full, but that is just an environmental issue, right? I won't impact the engine temp the way a too-empty tank would.

quote:
Did you retorque the heads after installing the new head gaskets (after the engine was run)?


No, I didn't. I am not getting any leaks at the gasket, nor am I seeing any coolant in the oil. What indicators should I expect if the torquing was an issue?

Thanks!
Mark
cybomancybomanMember
Mark,

I see what your problem is: you have 4 water temp gauges. That would confuse anyone!

Seriously, I put an automatic bleeder on the top right of the radiator in my '74. I used (if memory serves me correctly) a 6mm to 1/4" autometer gauge fitting. The 6mm male screwed into the radiator, and the 1/4" autobleeder (used on household radiators) screwed into the female end of this adaptor. You can turn the autobleeder open for manual bleeding, or set it where you like and it will bleed just the air/steam, and not fluid. You just leave it on your setting and anytime air gets trapped in the radiator, it will automatically bleed itself. It made bleeding the cooling system on that Pantera easy.

I realize you may have air trapped in the heads too and I've seen people install bleeders into the back of the heads.

(Sorry the picture is so small, it's the largest I could get it under 200kb.)

Michael

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6 6434Member
Hello Mark................ I second Cyboman's comment about using the coolant air bleeders on the back of both cylinder heads. And like Cyboman, I also have an air blead on the radiator but that bleeder also connects to a braided hose line that runs back and bleeds the air into the swirl tank. With the car running, all I ever do is jack up the rear end and go back and forth from head to head and bleed the air out of the system. I would take the car for a ride around the block and then bleed the heads again. Two sessions is usually all it needs. Let me know, I can send you a picture the head bleeders if needed.

Regards............ Doug.H
ea3528ea3528Member
Mark,

Have you ever tried an additive like Purple Ice?

I added it to my cat and it dropped the standard running temp to 170 (from 190). I can still run over 200 in traffic, but the difference was immediate and dramatic.

Also, we changed Blake's hoses over the weekend. It didn't take long to bleed the lines and ensure the system was tight. Is it possible you're getting air into the system?

Lastly, I had my gauges tested and cleaned over the winter. It took a few good runs before the water temp gauge began to respond normally again. I also replaced the entire sending unit wiring and grounds. Anyone who tells you that the stock wiring is still good after all these years (especially in the engine bay) is smoking something that I need to be smoking ... Eeker

Good luck!
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
Thanks for all the suggestions guys.

I will see if I can locate one of those auto-bleeders. I've never seen those before. Maybe a few burn-outs will help dislodge stubborn air pockets. It will certainly improve my enjoyment of this task.

My fans have shrouds (they come that way from Flex-a-lite) and good seals against the rad so that should not be the issue. In fact, the shrouds MAY be an issue and I might consider the "Woods Flaps" upgrade, although my problems are at low speeds not, sadly, at "over 150 MPH".

I really wanted to avoid drilling holes in my heads, but if this keeps up, that looks like a good idea.

I haven't tried the Purple Ice, but am using the Norosion which is supposed to help in a similar way (but not in my experience). I am not sure which ground affects the sender, but maybe a "fattie" will help me figure things out. Wink

Mark
ea3528ea3528Member
quote:
Originally posted by Mark Charlton:
I haven't tried the Purple Ice, but am using the Norosion which is supposed to help in a similar way (but not in my experience). I am not sure which ground affects the sender, but maybe a "fattie" will help me figure things out. Wink


The ground wires are daisy-chained together for each gauge and they run to the primary ground post, which is located on the chassis firewall just behind the speedo. There are between 13-17 ground wires that attach to that post. My recommendation would be to create a new ground post on the firewall and ground your gauges to it directly. From what I've learned, a poor ground is the main source of electrical frustration; however, it does sound like you have a legitimate cooling issue - so this would likely not fix the issue.

My limited knowledge tells me that you have air in your system ...

EA
J jb1490Member
quote:
No, I haven't thought of that. With only 18,000 miles I hoped it wouldn't be an issue.

I would be concerned that the nylon teeth on the cam sprocket would be getting brittle.

In reference to the pinging, have you checked to see if the outer ring of the harmonic balancer has slipped? Have you had to periodically adjust the initial timing? If so, then the outer ring may have rotated (slipped).

We're stuck with 91 octane pump gas (and who knows what's really in it), and I have never had any pinging from my engine. I have the same '71 engine as you.

quote:
No, but I can. Where should I measure those temps and what numbers should I expect of a normal engine temp?

Check the temps at the inlet and the outlet of the radiator with the engine running. Also check at the t-stat housing and water pump. Temp readings should be slightly lower than actual coolant temp.

quote:
Clearly my overflow tank is too full, but that is just an environmental issue, right? I won't impact the engine temp the way a too-empty tank would.


Yes and yes.

quote:
No, I didn't. I am not getting any leaks at the gasket, nor am I seeing any coolant in the oil. What indicators should I expect if the torquing was an issue?


It's possible that there may never be a problem. Indicators would be combustion gasses entering the cooling system; or coolant leaking into the cylinder; or the head gasket blown between cylinders.

IMHO, head gaskets should always be retorqued after the initial heat cycle. The head gaskets that I used were the ones that don't require retorquing. I had sequence and step torqued the head bolts to the 105 ft lbs torque spec. After the heat cycle, I checked the torque and it had dropped to 85 ft lbs.

YMMV

John
marlinjackmarlinjackThe Machinist #5723 AMARGOSA MACHINE 'Running on Empty- Middle of Nowhere'
...Looks to me as if the CAP on the 'Swirl' Tank is Dumping Coolant Too Soon!
The Cap should have a Pressure Rating of AT LEAST 16 Pounds!

If Your System can,t Hold the Pressure it will surely Overheat, this especially Includes ANY seepage Past the Hose Ends!!
Also Be absolutely Sure that Your Fans are turning in the Correct Direction!
It's Easy to get One or Both Wrong! And I have Both of Mine wired through Relays DIRECTLY from the Battery!!

Next, the coolant must be EXACTLY a 50/50 Ratio Solution, this raises the 'Boiling Point' to Over 230 Degrees F. The Difference is 'Night and Day', as far as Cooling. Anything less and Your right on the Edge of Overheating.

Last; is the 'By-Pass Restrictor Plate' installed under the Thermostat? I know You wrote that You did Not have this Problem in the Beginning, We are just 'covering All the Bases'!

If I think of anything else, I will add it Later.

Good-Luck with It!
lf-tp2511lf-tp2511Member
100% water is a better coolant than a water/antifreeze mixture. Period.

The addition of antifreeze, which is also an anti-boil, in fact diminishes the coolant properties of water.

PLEASE NOTE: The above is specific to the ability of the coolant to absorb heat . Just because it increases the boiling point does NOT mean it is a better coolant.

Thus, for maximum cooling efficiency a lower percentage of antifreeze is better. When I asked Bill at Ron Davis radiators in Arizona what to use in my new aluminum triple-pass they built for me, he said he personally recommends a 25% antifreeze mix; 25% will protect from freezing down to 10 degrees. The only additive Ron Davis Radiators recommends is Red Line Water Wetter.

Antifreeze is usually used in automotive coolant systems to ensure against engine damage caused by the freezing of the coolant. Likewise, it will increase the boiling point of the coolant, protecting the engine from heat damage (that is, steam pockets).

A 50%/50% mixture with water, in a system with a 15 pound pressure cap, lowers the freeze point to about -34 degrees, while raising the boiling point to about 270 degrees.

Antifreeze also contains rust inhibitors and water pump lubricants; but these can also be obtained as a separate additive not incorporating any antifreeze properties.

Pressurizing the coolant system will also raise the boiling point of the coolant. Panteras came stock with a 16 pound pressure tank on the surge-swirl tank. The overflow tank does have a cap, but it was not and should not be a pressure cap.

As the coolant abilities of water are diminished - that is, the % of antifreeze used is increased - the flow of the coolant needs to be increased to maintain the baseline coolant properties. This is in the range of 15% for a 50%/50% mix. In other words, if pure water keeps temperature at 180 degrees, when using the 50/50 mix you would need to increase coolant flow by 15% to maintain that 180 degrees.

Pressure - antifreeze % - coolant flow all interact on final coolant efficiency and performance.

Larry - flame suit on... Wink
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
You guys have been incredibly helpful and I really appreciate all of your input and suggestions.

My coolant is 50/50 (Prestone (I NEED the anti-freeze properties here) and de-ionized water) plus Norosion. I do have the brass restrictor plate installed under the t-stat. My fans are working well and turning in the right direction (pulling air thru the rad from behind). There is a LOT of heat blowing when the car is running hot, so the rad and fans seem to be doing their jobs well. One fan is thermostatically controlled (and comes on at a gauge-indicated 180°) and the other is switched manually at the dash by me. I assume (please correct me if I'm wrong) that at highway speeds, the fans are better NOT running as they would flow air at less than the speed of travel and thus reduce effectiveness of cooling.

Here is my plan of action:

• I will put back on the new 16 lbs pressure cap since the old RC82 unit is definitely NOT holding pressure (spews coolant at the tank neck when the car is hot).

• I will check/re-rout ground connections as needed

• I have ordered an air bleeding tool (similar to the Snap-On one Mark has) to assist evacuating air:

Photobucket

• I will drill holes in the thermostat

• I will quadruple check all my connections for possible air leaks

• I will re-bleed the system using the GPM™ (George Pence Method Smiler ) AND the air-evac tool

• I will run the car long enough to verify if problem solved, and if not:

• I will take temp readings at various locations as recommended (I might do this even IF the problem is fixed so I have a future reference set)

• I will have the coolant tested for combustion gases (man, I don't want "positive" results for that one) which is an interesting test I had not heard of before.

If none of the above resolves the issue, I will be enjoying our nice Rocky Mountain Rumble tour from the seat of my comfy, quiet and air conditioned rental car (which I would upgrade to a Mustang from a Fusion). The other suggestions (head bleeders drilled, timing gear/tensioner/chain upgrades) will have to wait as I don't have enough time to address them before the tour.

You guys are the best!

Mark
J jb1490Member
quote:
I will have the coolant tested for combustion gases

Mark,

I may have slightly mislead you on this one. I should have said to check for combustion gasses in the "COOLING" system, not in the "coolant".

Basically, the test consists of replacing the radiator cap with a testing device. The engine is then started and run for a few minutes. I would do this first.

Check the head bolt torque on a few of the bolts that have easy access (without removing anything). Start with about 90 ft lbs and see if the bolt holds or turns.

John
S shadetreeMember
Mark,

Are you using deionized water or distilled water? You may damage your radiator with deionized water as as it is hungry for ions and may attack the solder or other metals in your radiator. I once worked at a Culligan dealership and we sold deionized water to the semiconductor industry. One of our drivers topped up his radiator with our very expensive deionized water and and in a short time his radiator all but fell apart from the water attacking the solder and the copper. Maybe today's radiators are different but just a heads up.
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
Thanks for clarifying that John. Since at the moment I'm not getting ANY gas at the pressure tank, I'll remain cautiously optimistic that this is not the problem.

I should (and will) check the head bolt torque, but of course, by "without removing anything" you mean only removing the engine screen, upper coolant pipe, valve covers (better get new gaskets...). Big Grin

Yeah, I'm being a pussy, I know. I'm just getting (and who doesn't know this feeling all too well?) tired of "fixing" and not driving!

But since I'm going to need to drain coolant again, having this input before-hand really does help me save buckets of time by doing things in a logical order.

Mark
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
quote:
Originally posted by Shadetree:
Mark,

Are you using deionized water or distilled water? You may damage your radiator with deionized water as as it is hungry for ions and may attack the solder or other metals in your radiator. I once worked at a Culligan dealership and we sold deionized water to the semiconductor industry. One of our drivers topped up his radiator with our very expensive deionized water and and in a short time his radiator all but fell apart from the water attacking the solder and the copper. Maybe today's radiators are different but just a heads up.


Hmmm. I better check that. It was sold in jugs right beside the coolant in the auto parts store, but that probably doesn't mean anything these days. Thanks for the heads-up!

Mark
J jb1490Member
quote:
I should (and will) check the head bolt torque, but of course, by "without removing anything" you mean only removing the engine screen, upper coolant pipe, valve covers (better get new gaskets...).

The smiley face tells me that you may just be joking. Big Grin Soooo, just in case, just remove only the engine screen and check some of the head bolts by the the exhaust ports and spark plugs.....the easy ones. Wink

John
garth66garth66"When speed is the only thing that counts"
quote:
I accept that the gauges don't indicate accurate temps, but I make the assumption (yeah, I know) that it is functioning consistently and the numbers, while wrong, are relatively correct — at least as far as relative temperature changes goes.

FWIW, my stock Veglia gauge is accurate to within 2 degrees, verified multiple times with an IR temp gun on the block at the temp sender. Buy or borrow an IR temp gun to check your actual temps.
S samcMember
Hi Mark Just out of curiousity were the head gaskets double checked that any water jackets were not covered by the new gasket? Just wundering because if it never overheated before then backtracking everything that has been done so far might be wise.If the head gaskets are fine then I would still lean on air in the system Hope this helps
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
I really want to thank all of you who took the time to respond with great ideas and suggestions.

The person I owe the biggest THANK YOU to is my friend, fellow Pantera owner and expert problem-solver Bohdan G. He suggested my carb may have leaned out and wisely asked when I had last adjusted it. The answer did not impress him and he immediately came over and spent the evening helping (and teaching) me to adjust the carb. As an added measure of safety, I decided to move to a slightly cooler spark plug than I had been running (NGK UR5 from a UR4). As we were finishing up and doing some running tests, one of my fan relays started acting up causing the fans to stop working and we called it an evening.

Tonight another friend, neighbor and car-guy (who is less intimidated by volts than I am) came over to help trouble-shoot and locate a loose connection at the relay. Once all was tightened up, we went for a 45 minute drive (low and high-speed areas) and SUCCESS! The car ran like it did when I first got it. Strong and no pinging at all, even at the hottest temp. It never went over an indicated 195° on the gauge — WITHOUT using the second fan (my '71 has one switched fan, one thermostatically-controlled one). When we returned, I left both fans on and let the car sit idling for 30 minutes in my driveway and it stayed UNDER 195°.

I also took my new infrared temp sensor and found that the hottest part of my heads was 200°. My rad at the hot-in area read 193° when my gauge read just under 195° which suggests that the gauge is pretty close to accurate in my case (like Garth's).

Anyway, a HUGE thanks to everyone for their input, and ESPECIALLY Bohdan applause for SOLVING my conundrum.
party

Mark
nhpanterageorgenhpanterageorgeFormerly Geoshanna
Now I seem to have maybe the same issue. Last Friday night my car died due to a faulty coil wire. She pulls a lot stronger and has more power due to getting more spark. Now she is constantly running at the 200 mark on the gage. Should I also consider trying to richen up the mixture at this point to even the temp out? It's been in the 90's here all week. Or should I wait until I see what happens when it cools off here?

George
markcharltonmarkcharltonOld enough to know better and still young enough not to care. My '71 Pantera
Everything ran great for a while and then a week later some mountain driving coincided with more climbing temps. I concluded altitude sickness was the fault but after it persisted at lower elevations for a day longer I begged for help. Fortunately for me, John Christian (master engine builder from Detroit), Mike Drew (who did not drive my car prior to it acting badly and thus could not be blamed) and several others were around to assist. John pulled my carb completely apart, checked EVERY little tube, needle, screw and passage but could find no fault. He put it back together and I went for a test drive. The problem was gone and the car had never run better. After another 1000 km of crazy driving in the mountains and back home at sea level, the car still runs great and has ZERO overheating or running issues. Whatever John did (he swears he did nothing) exorcised some demons. In fairness, on our trip several guys had rough running issues and we have concluded that we got bad 94 octane gas somewhere. We were filling up twice a day so the odds are that some crap got sucked in and stuck for a while.

In my case, the overheating was accompanied by engine pinging (which I conclude was a result of running lean), so if you're getting that when your engine is at full running temp, and your timing is verified as correct, then checking fuel/air mix might help. Although I can't be certain exactly WHAT was giving me issues, the ONLY thing that actually corrected it was messing with the carb.

Good luck George.

Mark
ahudsonahudsonMember
Hey Mark, I just found and read this entire thread.

I'd have been no help in the diagnostics, but glad the overheating has been resolved. Plus, you made several dozen worthwhile cooling mods in the process!

Glad you got to enjoy your car, the driving, some worthwhile technical input. Just adds to the camaradarie. JC Christian did some work on my car while it was at Roush. You picked some good roadmates to have nearby for troubleshooting!

Glad it worked out.
4nford4nford"Live wrong and Perspire"
My 5-0 Pushbutton spends most of her time in the garage and sees little road time. I had to register her and took her down to get her smogged. While it ran on the smog sniffer, she overheated. I never had this problem before. Upon investigation I found that a fuse had deteriorated, it still worked intermittently but would cut off the fans when it didn't. When I checked it, the conductive parts fell off of the ceramic center. I changed all of the fuses in the block to be safe and haven't had a problem since. I remembered that Mike Drew had a similar problem.
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