Replaced radiator, now the engine is running hotter during stop and go driving

Have you checked the temp at the area of the sensor with your laser? I bet your gauge is off by maybe 6-8 degrees.

Another thing what temp thermostat did you install. Did you use the correct one? There is only one for the 351C

thanks for ideas will ck temp at sensor site and yes we have the thermotat rec by wilkinson robert shaw 180 i believe

Burping air from the radiator doesn't always work. There may still be a lot of air in the radiator. You may want to pull whatever fitting is in the top of your radiator (with the cooling system pressurized) and bleed air that way.

If you are not going to perform the vent system mods I've detailed in several past posts, then the second best thing to do is to install a drain cock in the top of one tank and manually vent the cooling system every once in a while. The top mounted drain cock will also help when you're filling the system .... much better results than raising & lowering the front & rear of the car.

The only other thing that comes to mind, be sure the fans are blowing air in the right direction.

-G

cooling system mods done by po new radiator has vent and no air when i vented
fans are correct
thenks for rep;y i am just out of ideas

I am chasing the same thing. I have done all of the modifications except hood vents. To many to list. In a post recently, it mentioned running without a thermostat. For test purposes only. Would you have to block off the By-pass passage in the brass piece that the termostat opens to block?

ok got some quality garage time today. had to pull the firewall out to install some koolmatand checked the temperature with my laser thermometer at the water pump and thermostat as Italford suggested
guage reading 180, thermostat 149 water pump the same.
btw the koolmat made a huge difference
used 2 of the 30 inch rolls, big difference in cabin temperature
life is good

Then you need to add a resistor across the terminals of your gauge. Will be in the 22 to 47 ohm range. This will lower your reading.

When I had my dash apart during restoration my temp gauge had two resistors wired in line with electrical tape. My guess is that this was dealer installed lol nice job. Long story short I installed an aftermarket mechanical temp gauge in the engine compartment so I can see it thru the rear window. I installed the sensor in the coolant tank. I monitor both gauges to avoid false readings. A resistor will help make the gauge more accurate.

question re the resister in the temp gauge. i believe my temp gauage is reading low is there anything that can be done for that?

quote:

question re the resister in the temp gauge. i believe my temp gauage is reading low is there anything that can be done for that?

Chris,

If your gauge has a resistor in its circuit, remove it and check the reading. If there isn't a resistor, make sure that the wire connections are clean and tight, and add a separate ground to the gauge. If that doesn't solve the issue, you may have a sender problem.

John

Pulled my thermostat. No difference

quote:

Pulled my thermostat. No difference

Did you block the hole below the thermostat?

Also note that certain replacement water pumps like the Weiand do not have the bypass hole in them and the Pantera does need that hole.

No, I was not sure how to block it off so that I could easily reverse everything.

quote:

No, I was not sure how to block it off so that I could easily reverse everything.

Hi Jeff,

Taking the thermostat out without blocking the hole is a guarantee of an overheating car... it allows a substantial amount of water to recirculate within the block without making a trip to the radiator.

IPSCO sells a block off plate for that hole or you could simply use the appropriate size freeze plug. Either method could be removed later when you decide to put the thermostat back.

OR, you could leave it in there and run a Winsor thermostat.

Scott

quote:

IPSCO sells a block off plate for that hole or you could simply use the appropriate size freeze plug.

If you use a freeze plug, make sure that you drill a small hole in its center for an air bleed.

John

http://ipsco.org/Pantera%20Par...ck%20off%20plate.htm

quote:

Originally posted by captaintobeys:
Pulled my thermostat. No difference

The trick with running a engine with no thermostat is to actually use a thermostat but remove it's mechanism so what is left is the thermostat "frame".

The "frame" of the thermostat is a calibrated restriction like a carburetor jet.

This slows the coolant flow to the correct speed, without it coolant will flow through the radiators to fast and not allow the coolant to be in the radiators long enough to lose the heat.

Problem is with a Cleveland you need something to deal with the bypass circuit as has been suggested or a large amount of coolant will recirculate inside the engine.

This is a photo of a thermostat that has had the "side skirt" removed allowing flow all the time but retaining the mechanism so when the temperature increases the bypass will still close.



It has the advantage that if it fails you will still have flow to the radiators, it's only the bypass that stops working.

I've found with electric fans the thermostat is not as important as it is with the fan belt driven mechanical fan that cars used to have unless you live somewhere that gets snow in winter.

I don't know if this will be benificial in every application.

To try it will cost the price of a thermostat.

I assume you just cut it off. I will have to check spare parts to see if I have another one. I do not have hood vents. I just can not find it in my heart to cut the hood. I am also thinking about an engine oil cooler. I pulled all the a/c stuff a long time ago. Not one of my priorities. So I was thinking about putting a cooler in the rear shroud that had the condenser in it.

[QUOTE]Originally posted by captaintobeys:
I assume you just cut it off. I will have to check spare parts to see if I have another one. /QUOTE]


Yes, the one in the photo was cut in a lathe, but if you were careful and patient i think you could cut it with a "Dremel" tool and a thin cutting wheel.

If you have a old one of the correct type use that. Then if it gets fouled up it's no big loss.

Just check the old one works ok by putting it in a pot of water on the stove, heat it and see if it opens up ok. If so that should be ok to use for this experiment. You can cut up a new one if you are satisfied with how it works out.

I respectfully disagree with Aus Ford regarding slowing down the coolant flow. I ran my cleavland for YEARS without the thermostat and it worked GREAT. I do however agree that the thermostat isn't really needed do to the electric fans unless you jump in your car and hit the freeway. In that case the motor WILL take a bit longer to get up to temp.

If you want to experiment, plug the hole under the thermostat with a freeze plug and run WITHOUT a thermostat and see what change happens. If you want to drill a small hole in the center as john suggests, then go ahead, however I ran with a solid freeze plug without any kind of issue for years.

I have heard people talk about slowing down the coolant flow, so it stays in the radiator longer, for years. There are people much smarter than I, that have dispelled that myth and with some simple tests, it could easily be proved or dis-proved...

quote:

Originally posted by ZR1 Pantera:
I respectfully disagree with Aus Ford regarding slowing down the coolant flow. I ran my cleavland for YEARS without the thermostat and it worked GREAT. I do however agree that the thermostat isn't really needed do to the electric fans unless you jump in your car and hit the freeway. In that case the motor WILL take a bit longer to get up to temp.

Yes, it is a controversial idea.

I think it is a case of what works in one car may not work in another.

But it might be worth a shot.

I think it depends on what radiators you have, what pipe work and tanks you have and probably what pump you have and what drive pulleys are being used.

Sorry guys, but I can't keep quiet any more. While I'm impressed with the enginuity and enginering skills here, the solutions are all IMHO compensating for a problem instead of correcting it. If a car suddenly runs hotter after replacing radiator, then either the radiator is wrong, or something was messed up during installation, like are all hoses tight, air pockets?

Case in point: My Pantera has 600HP and never overheats. Not even on tropic heat drives in France. Not even when idling through traffic after a 20 minute high rpm blast on the motorway. Sorry if this seems like insensitive bragging, my point is that my system is mostly stock, and it works. No louvers cut, no removing of thermostat, no slowing down or speeding up of flow. My system is stock, except I have two puller fans and the Halls radiator is tilted forward. Proper Cleveland thermostat. Proper coolant. Non-leaking system with two clamps on every connection. One fan is thermostat controlled, is on maybe 25% of the time, the other is manually controlled, I switch it on when in stop and go traffic in the heat. Don't know if I have to, but I do.

Your's could have a problem that I'm lucky enough not to have, but you probably won't fix it by cutting your hood, removing your thermostat or anything like that.

Good luck with it.

quote:

Sorry guys, but I can't keep quiet any more. While I'm impressed with the enginuity and enginering skills here, the solutions are all IMHO compensating for a problem instead of correcting it. If a car suddenly runs hotter after replacing radiator, then either the radiator is wrong, or something was messed up during installation, like are all hoses tight, air pockets?

Case in point: My Pantera has 600HP and never overheats. Not even on tropic heat drives in France. Not even when idling through traffic after a 20 minute high rpm blast on the motorway. Sorry if this seems like insensitive bragging, my point is that my system is mostly stock, and it works. No louvers cut, no removing of thermostat, no slowing down or speeding up of flow. My system is stock, except I have two puller fans and the Halls radiator is tilted forward. Proper Cleveland thermostat. Proper coolant. Non-leaking system with two clamps on every connection. One fan is thermostat controlled, is on maybe 25% of the time, the other is manually controlled, I switch it on when in stop and go traffic in the heat. Don't know if I have to, but I do.

Your's could have a problem that I'm lucky enough not to have, but you probably won't fix it by cutting your hood, removing your thermostat or anything like that.

Good luck with it.

Mikael

Mikael,

I agree with you completely!!!

If you re-read the postings, my first post was a reply to captaintobeys post where he said he removed the thermostat. I was concerned that he didn't plug the hole beneath the thermostat as that would be a sure way to cause an overheating condition. I never suggested removing the thermostat, he did that on his own. I believe he did it as a troubleshooting step, not as a permanent solution. Then aus ford and I discuss the merits of the thermostat and the coolant flow speed.

I actually agree with you completely and have said so in another post where augustboy was talking about cutting hood vents in his car because it was running hot. I told him to not do that and to track down the real problem.

Sometimes we have to go down a road we don't want to, when others do things that maybe, they shouldn't have done.

In fact, we don't have enough information from captaintobey to really even give a good recommendation because he hasn't told us about the nature of his cooling issue. We don't know if it is really overheating or if it is just running hot. We don't know if it has been tested with an accurate gauge to see if a problem really exists or if it has been boiling over.

What we do know is that be removed the thermostat WITHOUT plugging the hole beneath it so that was the ONLY issue I was trying to correct.

Take care, Scott

First, I do not expect anyone here to tell me what to do to eliminate my concerns. The car has never overheated and lost it's coolant. In stop and go, 90 degree plus days it will climb to 230 degrees. By then I am nervous enought to get out of traffic. On a steady state cruise it runs at 185 - 195 depending on different factors. I just want to be able to run it at track events and not worry. I am unemployed so money is short now. So I am looking at the little things and have plenty of time.

The colling changes include Fluidyne rediator, Flexilite fans with shroud, Pantera Electronics fan controller. Swirl/pressure tank conversion mentioned here years ago. With the air blead line from the radiator. Eldebrock pump with the 4.9 inch pulley. The A/c was pulled. Collant lines were dissconected from the heater core. Brass bypass fitting is in the block. It has the correct 333-180 thermostate. I have checked the gauge calibration by using a infrared thermometer.I can not tell you about the internals of the engine. I bought it years ago from a friend I trusted to build it correctly. He built it for himself. It is a Boss Motor with a Cam, Oiling system modifications, Everything blueprinted. When asked were the Redline should be, he suggested 8000 rpms. Many other checks that have been suggeted here over the years,

I quite easily could be chasing nothing.

so since it runs cool at speed but heats up to 230 in traffic I believe we have an air flow problem not a coolant flow problem. Are you running a single fan? Is it running at full capacity? my 2 cents.

quote:

so since it runs cool at speed but heats up to 230 in traffic I believe we have an air flow problem not a coolant flow problem.

It still could be either Tony but since he has increased his coolant speed already and he didn't report that it made any difference, I would tend to agree with you.

I don't like Fan Controllers. I see no need for them at all. When I ran my Cleveland, I used the coolant temp sensors without any issue at all. The stock setup works fine as long as you have a very good fan/shroud assembly...

quote:

:
so since it runs cool at speed but heats up to 230 in traffic I believe we have an air flow problem not a coolant flow problem.

Yes. Many stock Panteras did this from Day 1; Ford tried to fix this without spending any money- moving the sender to the surge tank 4 ft away from the heat source, adding two different resistors, and finally, changing to a 0-260F gauge with a built-in resistor after using up all the 0-230 gauges. All the late gauge actually does is not appear to be pegged. 230F is not particularly hot; my wife's '97 Z-28 has a single rad fan that doesn't even turn on until 230F. 'Hot' is 260F and above using a 16-lb rad cap. If your overflow tank is not spitting up, the engine is not overheated.

If the 351C bypass channel is blocked with an aftermarket waterpump or a 3/4" freeze plug in the brass washer, removing the thermostat will usually radically drop engine temps. There was a GT-5 at an open track event a few years ago that never got to 160F in many, many hard laps with an ambient temp of 98F. Around Las Vegas in the summer, the engine ran at 140F- too low to get heat out of the heater in winter or defrost the windshield. The owner didn't know the engine had no thermostat until I worked on it. After adding the proper unit, the engine temp immediately jumped to an average of 200F on a 900 mile cruise. And he could finally dispose of that dirty wipe-rag he used in place of a defroster.

If the bypass channel is NOT blocked, the engine WILL overheat at low speeds, assuming a marginal stock radiator and stock fans. The bypass channel ID is about 6% of the water pipe ID to the rad, so 6% of the boiling hot water from the engine will never make it to the radiator. Couple that to a stock rad that's 20% smaller than a Corvette rad (same size & power V-8 engines), add in too-small fans, and you have an overheating 351C. Once you get going above about 30 mph, the 'overheating' goes to sleep but adding 30-mph fans fixes the problem at all speeds. There are other factors, but this seems to be the main one IMHO.

so back to my original problem
have done all rec mods
my car acting jsut like jack descrives
my only question is that when i run it on hot day stop and go and it is hot both my new fans are on

BUT
lot of air moving benind the fan; when i get in fornt of the car a lot less coming through from the front
is that normal due to the greater surface area or do i ahve a shroud issue
be kind i am a novice mechanic

Are you saying that you are trying to push air through the radiator from the back towards the front?

no
i am wondering if the fans should be PULLING a stronger flow through the radiator

No way to tell how well your fans are performing without a flow meter. About the best thing you can do is throw a piece of paper or a business card in the front side radiator fins while the fans are on to see if the card/paper stays on. The best dual fans that flex-a-lite makes that fit our application are rated from 2500 to 3000 CFM and draw a lot of amps. I had a flex-a-lite set-up but ended up going with something else.

I have two things for you to consider. First are the head gaskets good? My car would do this exact thing. The head gaskets weeped coolant out the back and you could see it. Because the coolant system would not hold pressure steam pockets developed and the car would boil over. Going down the road it was okay but if it was hot outside and if I got caught in traffic the temp would climb.

Next have you checked your timing? What is your initial and total timing set to? Are you using vacuum advance? If so is connected to ported or manifold pressure?

At this point with all that I have read on your situation and having gone through this myself I'm guessing head gaskets.

Steve

Sorry, Joe- in my outline I assumed you had a shrouded sucker fan system with the shroud AND fans on the backside of the radiator (furthest away from the grille). And that both fans were spinning the correct direction. Is this true?

If so, all the electrical contacts between the fan motors and the battery including those on the fan relays should be thoroughly wire-brush-cleaned. The rated 2600 cubic feet per minute of airflow from (for instance) Flexilite shrouded sucker fans is with 13.2 VDC delivered to the fans. Wiring resistence can drop this to maybe 12.0V or even less, and the fans will then deliver far less than 2600 cu ft/sec. You or someone else can check this with a good VOM (volt-ohmmeter).
Alternatively, you can temporarily hot-wire the fans directly to the battery and purely from the resulting sound you should be able to tell if the air flow increased much. If it did, you've got wiring issues somewhere. Just don't try driving with the fans hot-wired; could be dangerous.

Slojoe, how does your new radiator differ from the old one ?

Is it the same or does it have more rows of tubes or less ?

Is it made from the same materials ? eg: alloy or copper and brass

Is the fin spacing the same ? eg: fins per inch


A thicker radiator with more rows of tubes and more fins, whilst having a greater surface area to radiate heat, may make it more difficult for electric fans to draw a adequate amount of air through the core at slow road speeds causing the car to run hotter in stop and go traffic.

If so you need more airflow/bigger fans.

My car does the exact same thing. Driving in traffic the engine temp just keeps climbing.

it is an aluminum fluidyne so thicker
have not measured fin spacing seems abt same

Is it possible for you to fit pusher fans in front of the radiator say 6 inches away ?



For the same size and power a pusher fan will move more air through the radiator than what a draw through fan will and they do not need a elaborate fan shroud like draw through fans do, just a basic housing around each fan.

In fact push through fans work best spaced away from the radiator so the air moved by the fan can induce a flow in the surrounding air so that more air than what is actually being displaced by the fan is pushed back towards the radiator.

It is kind of a multiplying effect. This effect does not occur with draw through fans and if there is the slightest amount of air leakage past the shroud of a draw through setup the amount moving through the radiator will be less than the fan displacement.

Fans push air much better than they can draw air. You can test this with a household fan. If you place your hand in front of the fan you can feel a strong flow of air, but if you place your hand the same distance behind the fan the airflow will be much weaker. This is the effect of the airflow itself inducing even further airflow in the surrounding air on the discharge side.

This is why it feels like you have good airflow on the discharge side of your draw through fans but there is poor flow on the inlet side (front of the radiator) the air flow on the outlet side is inducing further airflow from whatever air is nearby (not necessarily through air leaking or bypassing the shroud) and not from drawing all that air through the radiator core.

I have a big 16" draw though fan on my radiator and my engine gets hot in traffic. But counter intuitively the car runs cooler in stop and go traffic when i have the air conditioner on because the a/c switches on two push through fans in front of the condenser and even though the a/c dumps tons of hot air in front of the radiator the extra draft induced by their discharge is more effective at cooling the engine than the big 16" draw through fan.

Most of the Fan companies recommend a pull configuration and have stated that a pull style fan with a shroud is more efficient than a push style fan. This is why the MAJORITY of radiator fans you will find are in a pull through configuration. Almost every single Ron Davis Radiator is configured as a pull through. They do every motorsport on the planet including NASCAR.

I suspect your car runs cooler with the pusher fans on, simply because of the additional airflow of all three fans.

For an accurate test, you would need to run with a single or dual pusher fan ONLY. Record the results. Then run with the same single or dual fans but in a puller configuration and record the results.

The proper designed puller configuration with the proper shroud is the desired configuration. HOWEVER, if there isn't enough room for a good puller configuration, then a good pusher configuration may indeed win...