Thermostat malfunction?

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mbrew2

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My Car
1973 mustang convertible
Last summer I purchased a theromstat/restrictor kit that was supposed to be correct for a 351C. It was a 195 degree stat. During the summer I had problems with Temp running hot while in heavy traffic - up to 220-225 degrees. Now that its cooler, the temp gauge never gets over 180-185, even sitting at idle for long periods. My guess is that the thermostat is faulty and never closes to allow the cooling system to function properly. Does this make sense? I ordered it from tmeyerinc/track boss products that was recommended on this site.

 
Last summer I purchased a theromstat/restrictor kit that was supposed to be correct for a 351C. It was a 195 degree stat. During the summer I had problems with Temp running hot while in heavy traffic - up to 220-225 degrees. Now that its cooler, the temp gauge never gets over 180-185, even sitting at idle for long periods. My guess is that the thermostat is faulty and never closes to allow the cooling system to function properly. Does this make sense? I ordered it from tmeyerinc/track boss products that was recommended on this site.
1. did it run hot before you installed the t meyer t stat?

2. exactly what was included in the t meyer t stat kit?

3. how hot was the outdoor temp when it ran hot?

4. how far is your engine bored?

 
Last summer I purchased a theromstat/restrictor kit that was supposed to be correct for a 351C. It was a 195 degree stat. During the summer I had problems with Temp running hot while in heavy traffic - up to 220-225 degrees. Now that its cooler, the temp gauge never gets over 180-185, even sitting at idle for long periods. My guess is that the thermostat is faulty and never closes to allow the cooling system to function properly. Does this make sense? I ordered it from tmeyerinc/track boss products that was recommended on this site.
1. did it run hot before you installed the t meyer t stat?

2. exactly what was included in the t meyer t stat kit?

3. how hot was the outdoor temp when it ran hot?

4. how far is your engine bored?
When I bought the car it had a bad radiator that leaked. I replaced the radiator with a new factory style 3 core. I was still working on the car so not driving every day and didn't notice a problem.

The kit included a 351C correct style thermostat and the brass machined restrictor.

During summers down hear temps run 90's to near 100's.

Engine was rebuilt 13000 miles ago by PO. Have no spec's on internals. Just invoices.

Problem first surfaced this past summer after I installed new A/C system and started using the car as a everyday driver.

I replaced the thermostat just as precaution/preventive measure when I replaced the radiator and all hoses.

Temps now in Mobile range from 40's to mid 50's. Seems that engine should warm to 195 thermostat setting regardless.

 
The thermostat is supposed to be fully open at the advertised temperature, they begin opening 10°, or so, sooner.

How old is the water pump? The impeller is made of steel and can rust.

Do you have the correct fan shroud and diameter fan? Fan belt properly adjusted and tightened?

 
What exactly does this mean?

"Temps now in Mobile range from 40's to mid 50's. Seems that engine should warm to 195 thermostat setting regardless."

Exactly what radiator did you install?

 
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If the temp goes up in traffic and then goes down to the rated t-stat temp at highway speeds it probably isn't a t-stat issue. It is more likely a cooling capacity and/or airflow issue.

My guess is the newly added a/c condenser is restricting airflow through the radiator at idle. If that is the case you need to find a mechanical fan that moves more air or switch to an electric fan.

All this assumes that you have a properly fitting fan shroud, the fan the proper distance from the face of the radiator and the ignition timing set correctly.

 
The car was originally a factory A/C car. I replaced the factory unit with a modern system from Classic Auto Air. I replaced the radiator with a copper factory replacement. It has the original factory A/C shroud and fan.

I had posted here back then about overheating and suspected not enough air flow in traffic. Actually planned to install electric fans next summer. It was confusing to me that since it was originally a factory A/C car why the problem should surface when I replaced the factory system.

My thermostat concerns surfaced again now that the air temp is in the 40's to high 50's but the engine doesn't warm up to near the thermostat rating.

Excuse my lack of understanding about how the cooling system works, but I thought that in cooler weather the thermostat should remain closed until near its rating, then it would open and then cycle on an off as needed to maintain  that temp. I thought that in hot weather the same thing would happen and when it opened, cooler water from the radiator would cycle it closed, giving the fan/radiator time to cool the fluid some and on and on.

If it stays open all the time once it reaches near its rating, why run one at all?

 
The car was originally a factory A/C car. I replaced the factory unit with a modern system from Classic Auto Air. I replaced the radiator with a copper factory replacement. It has the original factory A/C shroud and fan.

I had posted here back then about overheating and suspected not enough air flow in traffic. Actually planned to install electric fans next summer. It was confusing to me that since it was originally a factory A/C car why the problem should surface when I replaced the factory system.

My thermostat concerns surfaced again now that the air temp is in the 40's to high 50's but the engine doesn't warm up to near the thermostat rating.

Excuse my lack of understanding about how the cooling system works, but I thought that in cooler weather the thermostat should remain closed until near its rating, then it would open and then cycle on an off as needed to maintain  that temp. I thought that in hot weather the same thing would happen and when it opened, cooler water from the radiator would cycle it closed, giving the fan/radiator time to cool the fluid some and on and on.

If it stays open all the time once it reaches near its rating, why run one at all?
The thermostat maintains minimum engine temp. Once it is open the cooling system capacity determines max engine temp. If you don't run a thermostat the engine will be slow to warm up and in the winter or at highway speeds may operate at too low a temp which can reduce gas mileage, cause drivability issues and increase engine wear. A street car should not be run without one.

Sorry, I misunderstood about the A/C. I thought it was a recent addition.

Its easy enough to test the thermostat in a pot of water on the stove with thermometer if you still think that is the issue.

You may also want to check your timing. Insufficient ignition advance will significantly increase combustion temps.

 
The car was originally a factory A/C car. I replaced the factory unit with a modern system from Classic Auto Air. I replaced the radiator with a copper factory replacement. It has the original factory A/C shroud and fan.

I had posted here back then about overheating and suspected not enough air flow in traffic. Actually planned to install electric fans next summer. It was confusing to me that since it was originally a factory A/C car why the problem should surface when I replaced the factory system.

My thermostat concerns surfaced again now that the air temp is in the 40's to high 50's but the engine doesn't warm up to near the thermostat rating.

Excuse my lack of understanding about how the cooling system works, but I thought that in cooler weather the thermostat should remain closed until near its rating, then it would open and then cycle on an off as needed to maintain  that temp. I thought that in hot weather the same thing would happen and when it opened, cooler water from the radiator would cycle it closed, giving the fan/radiator time to cool the fluid some and on and on.

If it stays open all the time once it reaches near its rating, why run one at all?
Ok, I'm still confused.

It sounds to me like you are now saying that it did not run hot before you changed any parts, is this correct?

Is your water pump stock?

Is your t stat bypass plate firmly in place?

You did not tell me exactly what radiator you installed so I can't help you there but you can take a photo of the top of the rad rubes, and measure the thickness of the core (not the tanks) then the spacing of the tubes from center to center.

As far as the engine temp not getting up to the t stat rating in cold weather, you did not tell us exactly what temp it does get to, but yes, it is possible the t stat is stuck open, but this is an easy thing to check.

Your understanding of how the cooling system works is correct, but there is also a "bypass" system on most cooling systems that allows some coolant to continuously flow thru the system all the time but this is usually a passage that is only around 1/" in diameter at the most.

The more info you supply, the better.

Also tommy k's timing suggestion is good, and I can tell you how to set it close to the optimum level for your particular car if you want, but my guess is that even if your timing is off, it will not be causing all of your problems, so you will still likely need to address another area as well.

.

.

 
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double post

 
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If you remove the thermostat and put in a pot of water on stove with a thermometer you can check the function.

If you remove a thermostat or use one with too cold of a rating the car will over heat for sure. Everyone says why? If the water is allowed to circulate at the speed that the water pump can move the water it does not spend enough time in the radiator to allow for cooling.

I always run a 192 deg. thermostat for that reason.

If you have an automatic transmission you should push it into neutral while stopped. That prevents the transmission from building heat sitting there.

I have told the story about my 73 C vert I bought off ebay many times. He said he never drove the car much after rebuilding and it sat for 25 years in garage not used. So I get the car spend couple years cleaning and detailing since if was mostly original paint and original interior. PO said his pit crew rebuilt the engine with all new parts.

Well I know I put the correct thermostat in and the first time I drove it got nearly to the H on the gauge and when I turned it off it blew coolant out. That is a sign of a backwards head gasket.

I did some checking and the bottom front corner of the head gasket should be almost square and the rear bottom has large radius. PO had put the R.H. head gasket on backwards that was causing the issue.

The engine is bored .050" over and I figure he just thought he had gone too far and that was the issue.

I have the original baffle in the block and an original 192 deg. Stant thermostat with AC and the big radiator. C-4 auto with high stall converter, cam, and headers. He also put 4-V on 2-V heads.

I can drive the car in the mountains in summer to over 5,000 feet with no heating issues.

The design of the Cleveland cooling system does not have an issue. If everything is as it should be you will not overheat.

Picture is original thermostat style with the hat that goes into the baffle that Ford put in the block. If I were you I would put the original baffle back in and get a Cleveland thermostat. Some will have a solid plug that extends out to do the same thing the hat does on the original.

Are you 100% sure your head gaskets are on correct? You can look with a mirror to check without removing the heads. Also have you checked for any exhaust gas in your radiator? Very small leak in head gasket will cause over heating. Make sure your timing is not excessive and that the vacuum advance is working.

















 
The car was originally a factory A/C car. I replaced the factory unit with a modern system from Classic Auto Air. I replaced the radiator with a copper factory replacement. It has the original factory A/C shroud and fan.

I had posted here back then about overheating and suspected not enough air flow in traffic. Actually planned to install electric fans next summer. It was confusing to me that since it was originally a factory A/C car why the problem should surface when I replaced the factory system.

My thermostat concerns surfaced again now that the air temp is in the 40's to high 50's but the engine doesn't warm up to near the thermostat rating.

Excuse my lack of understanding about how the cooling system works, but I thought that in cooler weather the thermostat should remain closed until near its rating, then it would open and then cycle on an off as needed to maintain  that temp. I thought that in hot weather the same thing would happen and when it opened, cooler water from the radiator would cycle it closed, giving the fan/radiator time to cool the fluid some and on and on.

If it stays open all the time once it reaches near its rating, why run one at all?
Ok, I'm still confused.

It sounds to me like you are now saying that it did not run hot before you changed any parts, is this correct?

Is your water pump stock?

Is your t stat bypass plate firmly in place?

You did not tell me exactly what radiator you installed so I can't help you there but you can take a photo of the top of the rad rubes, and measure the thickness of the core (not the tanks) then the spacing of the tubes from center to center.

As far as the engine temp not getting up to the t stat rating in cold weather, you did not tell us exactly what temp it does get to, but yes, it is possible the t stat is stuck open, but this is an easy thing to check.

Your understanding of how the cooling system works is correct, but there is also a "bypass" system on most cooling systems that allows some coolant to continuously flow thru the system all the time but this is usually a passage that is only around 1/" in diameter at the most.

The more info you supply, the better.

Also tommy k's timing suggestion is good, and I can tell you how to set it close to the optimum level for your particular car if you want, but my guess is that even if your timing is off, it will not be causing all of your problems, so you will still likely need to address another area as well.

.

I really don't know if the car had always run hot. I bought in late October and drove it some over the winter. The factory A/C did not work and heat controls only worked on 1 setting. I do remember it running hot due to losing coolant out of the leaking radiator.

The replacement radiator was supposed to be a factory A/C car 3-row I think.

I did not know that there was a Cleveland specific thermostat until I joined this forum. When replacing the radiator, I decided to replace all related components except the water pump. Several post here recommended the tmeyer unit as he was supposed to have the original tooling for the correct style with the "hat". I chose a 195 degree thermostat and the correct restrictor. I found that the thermostat in the motor was a standard Windsor-Type.

Got the new A/C system installed and running in June or July this year and immediately noticed overheating in traffic and would run around 200 on the highway.

Now that weather is cooler, it only gets to 180-185. Running stock water pump.

Haven't checked timing but car runs good with no issues or evidence of timing problems.  I used to set timing on my cars by setting it up for optimum advance (34 degrees?) at 2500-2600 rpm or whenever all advance was all in. Then let initial timing fall where it may. If that won't work on a Cleveland then please advise.

I guess the easiest thing to do is to first check the thermostat with the hot water test. 

I'll measure the radiator to see if it is correct for a factory A/C car.

.
 
The car was originally a factory A/C car. I replaced the factory unit with a modern system from Classic Auto Air. I replaced the radiator with a copper factory replacement. It has the original factory A/C shroud and fan.

I had posted here back then about overheating and suspected not enough air flow in traffic. Actually planned to install electric fans next summer. It was confusing to me that since it was originally a factory A/C car why the problem should surface when I replaced the factory system.

My thermostat concerns surfaced again now that the air temp is in the 40's to high 50's but the engine doesn't warm up to near the thermostat rating.

Excuse my lack of understanding about how the cooling system works, but I thought that in cooler weather the thermostat should remain closed until near its rating, then it would open and then cycle on an off as needed to maintain  that temp. I thought that in hot weather the same thing would happen and when it opened, cooler water from the radiator would cycle it closed, giving the fan/radiator time to cool the fluid some and on and on.

If it stays open all the time once it reaches near its rating, why run one at all?
Ok, I'm still confused.

It sounds to me like you are now saying that it did not run hot before you changed any parts, is this correct?

Is your water pump stock?

Is your t stat bypass plate firmly in place?

You did not tell me exactly what radiator you installed so I can't help you there but you can take a photo of the top of the rad rubes, and measure the thickness of the core (not the tanks) then the spacing of the tubes from center to center.

As far as the engine temp not getting up to the t stat rating in cold weather, you did not tell us exactly what temp it does get to, but yes, it is possible the t stat is stuck open, but this is an easy thing to check.

Your understanding of how the cooling system works is correct, but there is also a "bypass" system on most cooling systems that allows some coolant to continuously flow thru the system all the time but this is usually a passage that is only around 1/" in diameter at the most.

The more info you supply, the better.

Also tommy k's timing suggestion is good, and I can tell you how to set it close to the optimum level for your particular car if you want, but my guess is that even if your timing is off, it will not be causing all of your problems, so you will still likely need to address another area as well.

.

I really don't know if the car had always run hot. I bought in late October and drove it some over the winter. The factory A/C did not work and heat controls only worked on 1 setting. I do remember it running hot due to losing coolant out of the leaking radiator.

The replacement radiator was supposed to be a factory A/C car 3-row I think.

I did not know that there was a Cleveland specific thermostat until I joined this forum. When replacing the radiator, I decided to replace all related components except the water pump. Several post here recommended the tmeyer unit as he was supposed to have the original tooling for the correct style with the "hat". I chose a 195 degree thermostat and the correct restrictor. I found that the thermostat in the motor was a standard Windsor-Type.

Got the new A/C system installed and running in June or July this year and immediately noticed overheating in traffic and would run around 200 on the highway.

Now that weather is cooler, it only gets to 180-185. Running stock water pump.

Haven't checked timing but car runs good with no issues or evidence of timing problems.  I used to set timing on my cars by setting it up for optimum advance (34 degrees?) at 2500-2600 rpm or whenever all advance was all in. Then let initial timing fall where it may. If that won't work on a Cleveland then please advise.

I guess the easiest thing to do is to first check the thermostat with the hot water test. 

I'll measure the radiator to see if it is correct for a factory A/C car.

.
"The replacement radiator was supposed to be a factory A/C car 3-row I think."

Unfortunately, it does not work that way 45 years later. All chinese rads use tubes that are at least 20% smaller then us made rads. The biggest us made rad mfg sells their rads thru cool craft in az. They use the same size tubes the mfg used.

"I guess the easiest thing to do is to first check the thermostat with the hot water test."

The first thing to check on the t stat is to see if it is stuck open. The second thing to check is with hot water.

"Haven't checked timing but car runs good with no issues or evidence of timing problems."

A car can appear to start and run perfectly fine even though the timing is not ideal.

"Got the new A/C system installed and running in June or July this year and immediately noticed overheating in traffic and would run around 200 on the highway."

Did it have an ac condenser in front of the rad when you first bought the car?

Does it run hot with the a/c OFF?

Does t have a clutch fan?

"It was confusing to me that since it was originally a factory A/C car why the problem should surface when I replaced the factory system."

Because the block may have some rust in it and/or the engine is bored out pretty far.

A stock factory ford cooling system is designed to work on a stock factory engine. If the engine has been bored out, it is no longer stock etc.

.

 
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Ok, I'm still confused.

It sounds to me like you are now saying that it did not run hot before you changed any parts, is this correct?

Is your water pump stock?

Is your t stat bypass plate firmly in place?

You did not tell me exactly what radiator you installed so I can't help you there but you can take a photo of the top of the rad rubes, and measure the thickness of the core (not the tanks) then the spacing of the tubes from center to center.

As far as the engine temp not getting up to the t stat rating in cold weather, you did not tell us exactly what temp it does get to, but yes, it is possible the t stat is stuck open, but this is an easy thing to check.

Your understanding of how the cooling system works is correct, but there is also a "bypass" system on most cooling systems that allows some coolant to continuously flow thru the system all the time but this is usually a passage that is only around 1/" in diameter at the most.

The more info you supply, the better.

Also tommy k's timing suggestion is good, and I can tell you how to set it close to the optimum level for your particular car if you want, but my guess is that even if your timing is off, it will not be causing all of your problems, so you will still likely need to address another area as well.

.

I really don't know if the car had always run hot. I bought in late October and drove it some over the winter. The factory A/C did not work and heat controls only worked on 1 setting. I do remember it running hot due to losing coolant out of the leaking radiator.

The replacement radiator was supposed to be a factory A/C car 3-row I think.

I did not know that there was a Cleveland specific thermostat until I joined this forum. When replacing the radiator, I decided to replace all related components except the water pump. Several post here recommended the tmeyer unit as he was supposed to have the original tooling for the correct style with the "hat". I chose a 195 degree thermostat and the correct restrictor. I found that the thermostat in the motor was a standard Windsor-Type.

Got the new A/C system installed and running in June or July this year and immediately noticed overheating in traffic and would run around 200 on the highway.

Now that weather is cooler, it only gets to 180-185. Running stock water pump.

Haven't checked timing but car runs good with no issues or evidence of timing problems.  I used to set timing on my cars by setting it up for optimum advance (34 degrees?) at 2500-2600 rpm or whenever all advance was all in. Then let initial timing fall where it may. If that won't work on a Cleveland then please advise.

I guess the easiest thing to do is to first check the thermostat with the hot water test. 

I'll measure the radiator to see if it is correct for a factory A/C car.

.
"The replacement radiator was supposed to be a factory A/C car 3-row I think."

Unfortunately, it does not work that way 45 years later. All chinese rads use tubes that are at least 20% smaller then us made rads. The biggest us made rad mfg sells their rads thru cool craft in az. They use the same size tubes the mfg used.

"I guess the easiest thing to do is to first check the thermostat with the hot water test."

The first thing to check on the t stat is to see if it is stuck open. The second thing to check is with hot water.

"Haven't checked timing but car runs good with no issues or evidence of timing problems."

A car can appear to start and run perfectly fine even though the timing is not ideal.

"Got the new A/C system installed and running in June or July this year and immediately noticed overheating in traffic and would run around 200 on the highway."

Did it have an ac condenser in front of the rad when you first bought the car?

Does it run hot with the a/c OFF?

Does t have a clutch fan?

"It was confusing to me that since it was originally a factory A/C car why the problem should surface when I replaced the factory system."

Because the block may have some rust in it and/or the engine is bored out pretty far.

A stock factory ford cooling system is designed to work on a stock factory engine. If the engine has been bored out, it is no longer stock etc.

"Now that weather is cooler, it only gets to 180-185."

That is plenty warm enough and may be about right for the 192 t stat you have. The t stats are not always perfect and the temp gauges are not always perfect so I don't see an obvious problem with this particular point.

"Got the new A/C system installed and running in June or July this year and immediately noticed overheating in traffic and would run around 200 on the highway.

So it runs at a steady 200 on the open highway in the 100 degree summer heat with the ac ON?

"Several post here recommended the tmeyer unit as he was supposed to have the original tooling for the correct style with the "hat".

Post a photo of the t stat from the side if you can and post one of the bypass plate. 

.
 
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How are you measuring the temperature? An accurate infrared thermometer aimed at the thermostat housing is the most accurate and consistent, no fluctuations that electrical analog gauges can have.

When the temperature reading is low are you running the heater? A heater acts as a small radiator.

185° in the cold weather is acceptable for a 195° thermostat. Thermostats don't pop open when they reach the advertised temperature. They begin to slowly open at least 10° before and are supposed to be fully open at the advertised temperature. As the engine cools down the thermostat slowly closes until it is completely closed.

 
The other easy thing to check is to see if the head gaskets are on correct. You can look with a mirror and if there is a big radius on the front bottom corner it is backwards and you need to pull head or heads back off and correct. The correct Cleveland thermostat is not difficult to find. ORiley had them here and also Advance. I had them pull one and looked at it.

Someone mentioned the water pump but they are way over sized. I think the impeller is SS so no rust to eat away. When building race engines we use to take every other impeller off capable of way too much water flow as stock. My boss had sizes of washers he put in for each type engine for racing to take the thermostat out but still have a restriction to keep the water from going too fast.

BTW an aluminum radiator will not cool as efficiently as a copper one. Nothing beats copper. You have to have air flow to cool the water.

I ran a .125" over bore flathead with cam and shaved heads on the street for years and never had overheating issues.

My Cleveland is .050" over and I can drive in town with no issues in July. Once you get everything right there will be no issues. No reason to change any of the design of a Cleveland because one person thinks so. Meyer is a great racer but they did ZERO testing and can show no side by side results for their suggested changes. Ford spent thousands of hours in testing they did not.

 
Last summer I purchased a theromstat/restrictor kit that was supposed to be correct for a 351C. It was a 195 degree stat. During the summer I had problems with Temp running hot while in heavy traffic - up to 220-225 degrees. Now that its cooler, the temp gauge never gets over 180-185, even sitting at idle for long periods. My guess is that the thermostat is faulty and never closes to allow the cooling system to function properly. Does this make sense? I ordered it from tmeyerinc/track boss products that was recommended on this site.
1. run a 180 degree stat, 14-16 degrees initial timing. If it detonates,  recurve dizzy mech. advance  to come in later

2. get 19 inch seven blade flex fan, factory shroud and MOST importantly, space the fan so 1/3 blade width is just inside shroud opening. I don`t know how many cars I have seen with improper fan/shroud spacing.

3. overheating only in traffic needs air flow management. At freeway speed as well, thin cylinder walls, ect.

 
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