I have a 1974 Pantera which I've updated the cooling system using the example set in sticky #3 from this forum. Fluidyne Pantera radiator with dual sucker fans, condenser in front. Weiand waterpump, not modified, with a water pump reduction pulley.  Above 90 degrees ambient the 260 temp guage, with Pantera-Electronics compensator, appears to peg high at speed, as soon as it comes back to a normal cruise speed or idle it will read about 192.  To me this indicates an air pocket.

I'm purging the system again this morning with the real elevated,  13psi cap, ran it up to about 110 degrees and shut it down, purged the air and got minor overflow out the tube. Fluid topped off before running. Topped off again and ran until cooling fans turned on and shut down, purged and overflow was slightly more tha 1 quart.  Took temp reading on coolant and it was 150 degrees.  Ran test a 2nd time, holding rpm at 2000 for 3 minutes, purged and overflow close to 1 gallon, temp reading 190 degrees.  Also in the the past I have pulled the temp sending unit and water poured out.  I'm not familiar if that water coming out would be before or after the thermostat..

I'm stumped as 150 would not be opening the kool-flow thermostat it seems.  Perhaps the waterpump pulley should be returned to oem?

I'm open to suggestions.  FYI, I've tried in the past to loosen the water ports in the block with no luck, they are the square head plug not the socket head cap screw.

 

Last edited by maraudermike
Original Post

Has your motor been rebuilt? I have heard in the past with a Cleveland that refused to cool properly, after being rebuilt that the head gaskets were put on backwards and this caused cooling inconsistencies / problems.

I am sure there will be others that chime in and have a better understanding, but hopefully you can cross this scenario off your list. Good luck.

I thought that air pockets on the sender read low, not high. 

I’m sorry, but your description isn’t really clear as to whether the car is truly overheated or not. 

it sure sounds like a gauge or electronics problem to me.

 

if the temperature was pegging on a high speed run and then you slow down there’s no way your cooling system would instantly return to 190°

Are you burping fluid after you stop?

 

can you get someone to ride in the passenger seat with an IR gunand get temperature readings when the gauge is pegged and when it’s normal?

 

Good Luck -

Rocky

For a start, every Pantera owner should have one of these: 

https://www.amazon.com/WIN-MAX...591459348&sr=8-7

It's a vacuum filling device for your cooling system. It pulls a strong vacuum in your cooling system, then sucks the coolant out of your 5 gallon bucket, that's sitting on the floor beside the car, and fills your cooling system. No more spilled coolant and no more trapped air bubbles. It's a diagnostic tool too because it allows you to leave your system under vacuum for as long as you like, to make sure there are no leaks. Here's the best part. The very tool in the amazon link used to cost $155 at Summit. Snap-On also sold this exact tool for over $250 but now Amazon sells it for less than $50!  

Vacuum Device

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Rocky, the engine has never overheated. I'll try having some ride with me.  I have in the past gotten out and using IR seen head readings at the back of the head of 184, never higher.

Good luck, Mike!

You might try and keep an eye on the voltage of your car during your high speed runs as well.  You can get one of those volt meters that plugs into the cigarette lighter, or hook a meter to the hot side of the fuse box. 

There are some threads around here on the temp sender resistance - I THINK it gets lower as the temperatures increase...  is it possible that the sender is shorting under the vibration of your high speed operation?

 Again, good luck!

Last edited by rocky

The gauge pegging at speed sure sounds more like a high voltage than erroneous reading. Normally cooling at speed isn't an issue with increase air flow through the radiator. Do you have the fans with an integral shroud? I have know cases where they become restrictive to airflow at speed, but that was in excess of 150 mph. Is it possible they are being spun by the natural airflow and acting as generators during high speed runs? I have also known fan blades to be on backwards or wired backwards as well, they can still push air at lower speed but not counteract the increased resistance at high speed.

Try driving in a lower gear at sustained high rpm to help determine whether it is an airflow across the radiator or water pump / coolant issue.

joules,

Thanks for that info.  I do have cooling fans with integral shroud and they are turning the correct direction.  FYI my high speed runs are 55 to 80 mph as I don't track the car.

The possible electrical issue you are speaking of would mean I might be getting a voltage in excess of 14.5 volts causing an issue?

Hi Mike -

From my view, that’s just a guess, but I think Joules and I both think (for whatever it’s worth) that it sounds like an instrumentation problem vs. a “real” overheat condition. 

Any chance to change out your temperature sender?

 

Rocky

 

 

 

Rocky,

I'll change it out again as I've thought of that in the past.  I'm using the Stadard TS58 sender.  Other suggestion for sender unit?

 

Hi Mike -

I don’t have another suggestion, it that sender works correctly some of the time, it’s probably the right choice.

Regards

 

@davidnunn posted:

For a start, every Pantera owner should have one of these: 

https://www.amazon.com/WIN-MAX...591459348&sr=8-7

It's a vacuum filling device for your cooling system. It pulls a strong vacuum in your cooling system, then sucks the coolant out of your 5 gallon bucket, that's sitting on the floor beside the car, and fills your cooling system. No more spilled coolant and no more trapped air bubbles. It's a diagnostic tool too because it allows you to leave your system under vacuum for as long as you like, to make sure there are no leaks. Here's the best part. The very tool in the amazon link used to cost $155 at Summit. Snap-On also sold this exact tool for over $250 but now Amazon sells it for less than $50!  

Vacuum Device

That cooling system pressure tool is great for getting air pockets out of the Pantera cooling system! No more jacking the back of the car up and trying to force the air out and other issues. I recommend that kit for anyone that works on their Pantera.

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