'92 Taurus Heater Issues - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

turbo79 · 06-19-2008, 12:03

I have a '92 SHO with an EATC system, and the heater function works poorly and inconsistently.

Most of the time it blows cool air despite the temperature setting. I just happened to be under the hood recently while at a gas stop, and I felt the heater hoses and the aluminum outlet from the engine and they were fairly cool. Yet, a couple of days later I did the same, found that the heater hoses were properly warm and, turning the temperature up, found that the system was putting out heat. The next day the "cool" condition returned. It stays cool most of the time, even after a 35 mile commute.

The engine comes up to proper operating temperature (according to the temp. gauge, which has a new sending unit) and does not leak any coolant.

I will add that the air conditioning does not work either, but that seems to be a separate issue.

I have run the self-test on the EATC head, and no trouble codes are being set.

Is it safe to assume that there is no valve under the inst. panel on the inlet or outlet to the heater core that controls the coolant flow?

Thank you for any tips!

Tom F.
Deer Island, Oregon

By the way, my fiance and I just took this car on a near 3,000 mile road trip from Oregon to Colorado and back, first time on an extended trip in this rig, and it sure is a great open highway driver. Really good power considering the altitudes in CO.

SHOZ123 · 06-19-2008, 12:40

There is no valve. Sounds like you have air in your cooing system and are low on coolant.

Be sure the radiator cap is good and that the radiator tanks aren't leaking. A properly sealed cooling system will purge itself of any air in the coolant. This requires pressure and the ability to hold a vacuum when cooling down. The radiator will leak on the drivers side when cold usually. As the coolant and tank heat up they will seal.

turbo79 · 06-19-2008, 14:58

Quote:

Originally Posted by SHOZ123

There is no valve. Sounds like you have air in your cooing system and are low on coolant.

Be sure the radiator cap is good and that the radiator tanks aren't leaking. A properly sealed cooling system will purge itself of any air in the coolant. This requires pressure and the ability to hold a vacuum when cooling down. The radiator will leak on the drivers side when cold usually. As the coolant and tank heat up they will seal.

I did suspect that this (air in the system) might be the issue before I installed a new radiator, and cap, as the core to driver side tank seal was leaking. The car had the same symptom (no heat to speak of), but now it does not lose any coolant, this after a 3,000 mile road trip that included a lot of 80 mph cruising (Colorado) on I-70. The system now definitely holds pressure, but I'm not sure how to check for holding vacuum or determining if there is air in the system.

The tank would wisp hot air and a little coolant with the old radiator when it was hot as well as cold. Now it seems air tight.

Thank you for the response...

**tbird100636** · 06-19-2008, 19:02

Quote:

Originally Posted by turbo79

I have a '92 SHO with an EATC system, and the heater function works poorly and inconsistently.

Most of the time it blows cool air despite the temperature setting. I just happened to be under the hood recently while at a gas stop, and I felt the heater hoses and the aluminum outlet from the engine and they were fairly cool. Yet, a couple of days later I did the same, found that the heater hoses were properly warm and, turning the temperature up, found that the system was putting out heat. The next day the "cool" condition returned. It stays cool most of the time, even after a 35 mile commute.

The engine comes up to proper operating temperature (according to the temp. gauge, which has a new sending unit) and does not leak any coolant.

I will add that the air conditioning does not work either, but that seems to be a separate issue.

I have run the self-test on the EATC head, and no trouble codes are being set.

Is it safe to assume that there is no valve under the inst. panel on the inlet or outlet to the heater core that controls the coolant flow?

Thank you for any tips!

Tom F.
Deer Island, Oregon

By the way, my fiance and I just took this car on a near 3,000 mile road trip from Oregon to Colorado and back, first time on an extended trip in this rig, and it sure is a great open highway driver. Really good power considering the altitudes in CO.

How long does it take to get to operating temp.??? If it takes a long time and there is no air in the system then my first guess would be a stuck open thermostat. What was the temp. of the upper radiator hose when the heater hoses were cool??? The upper hose would be cool too if it were a stuck open thermostat.

turbo79 · 06-20-2008, 07:48

Quote:

Originally Posted by tbird100636

How long does it take to get to operating temp.??? If it takes a long time and there is no air in the system then my first guess would be a stuck open thermostat. What was the temp. of the upper radiator hose when the heater hoses were cool??? The upper hose would be cool too if it were a stuck open thermostat.

The upper rad. hose was very warm, and the temp. gauge is rising to operating temp. levels. Can air possibly somehow get trapped in the heater core?

SHOZ123 · 06-20-2008, 08:14

Again, if the cooling system can hold the rated cap pressure and can maintain a vacuum on cool down the air will rid itself over a few heating-cooling cycles. You can tell if the vacuum part is working by watching the overflow bottle. It will draw the coolant back into the radiator as the engine cools down.

turbo79 · 06-20-2008, 14:55

Quote:

Originally Posted by SHOZ123

Again, if the cooling system can hold the rated cap pressure and can maintain a vacuum on cool down the air will rid itself over a few heating-cooling cycles. You can tell if the vacuum part is working by watching the overflow bottle. It will draw the coolant back into the radiator as the engine cools down.

It doesn't seem to draw much coolant from the overflow bottle on cool down. I'm mystified...

SHOZ123 · 06-21-2008, 00:10

Then there is a vacuum leak on cool down. Is the radiator cap new?

turbo79 · 06-23-2008, 12:27

Quote:

Originally Posted by SHOZ123

Then there is a vacuum leak on cool down. Is the radiator cap new?

New cap, yes. From a Ford dealer. Could it be that the cap isn't sealing properly on the vacuum "side" or "function?"

SHOZ123 · 06-23-2008, 12:42

Unlikely. Is the radiator neck clean where the cap gasket seals?

My bet is the radiator tank on the drivers side. When the engine is cold and after it's been sitting 24 hours (longer is better) look under the radiator on the drivers side. See if there is any signs of moisture.