Taurus SHO 1992 overheating persistent mystery

[vladimir]

My 1992 Ford Taurus SHO has a heating problem and I've tried everything to solve it and nothing has worked. If anyone has had this problem and can help, I'd be grateful.

Here's the problem, when you are driving in the vehicle traffic or when you need to stop the radiador fan starts working when the temperature gauge needle reaches the letter O. And turn off when is in the letter R.
From this point on, it will oscillate between the letter O and R, turning the radiator fan on and off. The temperature only drops a little if I drive at a higher speed.

In this car, the radiator and water pump have already been replaced. The radiator cap, the thermostatic valve, ETC sensor and the temperature gauge sensor (all new) and original Motorcraft, but the problem has never been solved, persisting for 2 years. I don't drive the car much.
I've tried the procedure to remove air from the cooling system several times, but nothing changes. I've already replaced the instrument panel and hoses and I can't solve it.
There is no water leaking at any point. I have already done the pressure test and also bypassed the heater. I have also checked the signal on the sensors and everything is normal. However, the indicator pointer works high and oscillates. This is not normal.
I have attached a photo of the temperature indicator.
If anyone has any information about this problem, I would appreciate it.

 

[Devin]

What temperature of thermostat do you use? What're the daily temps where you are?

 

[Irish Pride]

Technically speaking, if your car stays in the N O R M A L range then your car is not overheating and in my opinion is in fact normal. Every one of my cars reads different. Some do like you are describing and some stay below M at all times.

If there is any air trapped in the system it will be between the engine and the heater core. If your heat gets nice and hot and stays consistent and both heater hoses at the core get nice and hot then you don't have any air trapped.

I would replace the thermostat with a high flow unit. The one that I use is called an Ultrastat. It still has the same temp rating(195) but has a wider opening so more coolant can circulate faster. The gauge is controlled by the temp sensor next to the thermostat. Try installing a different, non Motorcraft sensor and see if that changes your gauge display.

-Chad

 

[vladimir]

What temperature of thermostat do you use? What're the daily temps where you are?

The sensors I am using are all original Motorcraft as shown in the photos. I replaced them all to eliminate any doubts. I put the new radiator cap on and then found the older model that is currently installed in the car, all original as well. But nothing changes the functioning.
I live in Brazil, in the city of São Paulo. In the summer the temperatures reach 35 Celsius and in the winter around 5 Celsius, however, in any situation the problem is the same, there is no change.

 

[vladimir]

Technically speaking, if your car stays in the N O R M A L range then your car is not overheating and in my opinion is in fact normal. Every one of my cars reads different. Some do like you are describing and some stay below M at all times.

If there is any air trapped in the system it will be between the engine and the heater core. If your heat gets nice and hot and stays consistent and both heater hoses at the core get nice and hot then you don't have any air trapped.

I would replace the thermostat with a high flow unit. The one that I use is called an Ultrastat. It still has the same temp rating(195) but has a wider opening so more coolant can circulate faster. The gauge is controlled by the temp sensor next to the thermostat. Try installing a different, non Motorcraft sensor and see if that changes your gauge display.

-Chad

Hello Chad.

Thanks for the feedback.

Yes, technically it is within the normal range, but it should not be working so close to the red line. The fact that it is oscillating is also not normal.

I used to have a 1995 Taurus LX and it was working with the needle on the gauge at letter A. I have a friend who has a 1992 SHO and does not have this fluctuation and the gauge also stays at letter A.
I have not yet installed a sensor other than the original, only other sensors but always original, but it is an option to evaluate if there is any change.

 

[Irish Pride]

Hello Chad.

Thanks for the feedback.

Yes, technically it is within the normal range, but it should not be working so close to the red line. The fact that it is oscillating is also not normal.

I used to have a 1995 Taurus LX and it was working with the needle on the gauge at letter A. I have a friend who has a 1992 SHO and does not have this fluctuation and the gauge also stays at letter A.
I have not yet installed a sensor other than the original, only other sensors but always original, but it is an option to evaluate if there is any change.

I would switch the front temp sensor to a non Motorcraft and go with a high flow thermostat and see what that does. You can also switch to a 180° thermostat to see if that helps but that might affect your fuel mileage if not tuned for it.

I've had SHOs do exactly what you are describing and as long as the actual coolant temp is not getting into the 220+ range then I consider that normal and a quirk of that particular car.

-Chad

 

[FastCAD]

Hello Chad.

Thanks for the feedback.

Yes, technically it is within the normal range, but it should not be working so close to the red line. The fact that it is oscillating is also not normal.

I used to have a 1995 Taurus LX and it was working with the needle on the gauge at letter A. I have a friend who has a 1992 SHO and does not have this fluctuation and the gauge also stays at letter A.
I have not yet installed a sensor other than the original, only other sensors but always original, but it is an option to evaluate if there is any change.

Hi. I agree with Chad my '91 acts like you describe for the past 34yrs. and 250 thousand miles in hot/humid Miami weather and the heads have never been off..
With the a/c off the temp will always quickly climb to O or N and then the radiator kicks in and it will drop to M and it quickly starts all over again no problems *as long as the second ECM / fan control temp sensor is working*
With the a/c on in city driving the temp will go to R or above in very hot summer driving. I have been told that with the a/c on above 65mph the ECM will cut the radiator to preserve the pulleys. which I assume to be true because if I push the SHO to hi-revs the temp will go up to R and above until I back off.
I use a "RAD" brand 'FAILSAFE' thermo (it can not fail closed). It has worked well for many years.
I hope this helps,
"keep the shiny side up"
p.s. You get all Motorcraft parts in Brasil??

 

[vladimir]

Hi. I agree with Chad my '91 acts like you describe for the past 34yrs. and 250 thousand miles in hot/humid Miami weather and the heads have never been off..
With the a/c off the temp will always quickly climb to O or N and then the radiator kicks in and it will drop to M and it quickly starts all over again no problems *as long as the second ECM / fan control temp sensor is working*
With the a/c on in city driving the temp will go to R or above in very hot summer driving. I have been told that with the a/c on above 65mph the ECM will cut the radiator to preserve the pulleys. which I assume to be true because if I push the SHO to hi-revs the temp will go up to R and above until I back off.
I use a "RAD" brand 'FAILSAFE' thermo (it can not fail closed). It has worked well for many years.
I hope this helps,
"keep the shiny side up"
p.s. You get all Motorcraft parts in Brasil??

Thanks for the feedback.

I've been driving, albeit briefly, for two years with this problem and the engine is still intact. However, it wasn't like that, there was no fluctuation in the temperature gauge.

About SHO parts in Brazil, there's nothing here about this car, I have to bring everything from the US. I've had this car since 2006 and at the time I found many parts available on Ebay and ended up stocking up a small amount. I still buy on Ebay and other stores, but it's a fact that it's getting harder and harder to find parts and they're getting more expensive.

Taurus SHOs are very rare in Brazil. Some were imported independently. Here the LX and GL versions are more common, which were brought by Ford in 1994, 1995 and 1997, but the vast majority have already been scrapped.

 

[Irish Pride]

I have Brazilian tail lights on my 95 Moonlight Blue. A good friend of mine up here in Nashville is from Brazil and he sourced a pair for me when he went home once. He imported an Opala when he moved here and I'm in love with his car. I told him that I want to buy it if he ever sells it but he promises that he never will.

-Chad

 

[SHOCALL]

That is a sick ride Chad, holy #&$!.
That blue is unreal.

 

[vladimir]

I have Brazilian tail lights on my 95 Moonlight Blue. A good friend of mine up here in Nashville is from Brazil and he sourced a pair for me when he went home once. He imported an Opala when he moved here and I'm in love with his car. I told him that I want to buy it if he ever sells it but he promises that he never will.

-Chad

View attachment 94512
View attachment 94514

Hello Chad.
This taillight is rare in the US, very good. Good experience. These are really the taillights of the Brazilian model. In addition to the taillights, the mirrors are different. At the time, Brazilian legislation did not allow the taillights to be all red. The turn signal had to be orange. Today this restriction no longer exists. The rest of it doesn't change. It's funny, here we import the original taillights from the US and also the mirrors.
Regarding the Opala, it is a very desired car here, especially the version equipped with 6-cylinder engines. In the past, there were very coveted cars here, one of them was the Opala, another the Maverick V8 and the Dodge Dart. We also had the Ford Galaxy.
Generally, in good condition, they don't want to sell. And if they do, the price is quite high.

 

[Irish Pride]

Hello Chad.
This taillight is rare in the US, very good. Good experience. These are really the taillights of the Brazilian model. In addition to the taillights, the mirrors are different. At the time, Brazilian legislation did not allow the taillights to be all red. The turn signal had to be orange. Today this restriction no longer exists. The rest of it doesn't change. It's funny, here we import the original taillights from the US and also the mirrors.
Regarding the Opala, it is a very desired car here, especially the version equipped with 6-cylinder engines. In the past, there were very coveted cars here, one of them was the Opala, another the Maverick V8 and the Dodge Dart. We also had the Ford Galaxy.
Generally, in good condition, they don't want to sell. And if they do, the price is quite high.

What is different about the mirrors? Do you have pics of yours?

-Chad

 

[vladimir]

What is different about the mirrors? Do you have pics of yours?

-Chad

Yes, of course.
The difference between the Taurus Brazil mirror is that it is articulated. If someone bumps into the mirror, it will articulate. This was also a requirement of Brazilian legislation to prevent injuries in the event of a person being run over or being hit by a motorcyclist.
Personally, I think this mirror is ugly. The original model from the US is much nicer.
I have included some photos. The red car is a 1995 LX that I owned. There is a photo from when I bought it and after I replaced the mirror. I have also included other photos to get more details.

 

[Devin]

The mirrors on the LX look tiny!

 

[vladimir]

The mirrors on the LX look tiny!

exactly. I didn't like it.

 

[Bret Johnson]

My 1992 Ford Taurus SHO has a heating problem and I've tried everything to solve it and nothing has worked. If anyone has had this problem and can help, I'd be grateful.

Here's the problem, when you are driving in the vehicle traffic or when you need to stop the radiador fan starts working when the temperature gauge needle reaches the letter O. And turn off when is in the letter R.
From this point on, it will oscillate between the letter O and R, turning the radiator fan on and off. The temperature only drops a little if I drive at a higher speed.

In this car, the radiator and water pump have already been replaced. The radiator cap, the thermostatic valve, ETC sensor and the temperature gauge sensor (all new) and original Motorcraft, but the problem has never been solved, persisting for 2 years. I don't drive the car much.
I've tried the procedure to remove air from the cooling system several times, but nothing changes. I've already replaced the instrument panel and hoses and I can't solve it.
There is no water leaking at any point. I have already done the pressure test and also bypassed the heater. I have also checked the signal on the sensors and everything is normal. However, the indicator pointer works high and oscillates. This is not normal.
I have attached a photo of the temperature indicator.
If anyone has any information about this problem, I would appreciate it.

I would look at the cooling fan. It's been a while since I had my SHO, but the cooling fan on my 91 got to where it was running slower than spec and would show similar symptoms. I ending up getting motor rebuilt with new brushes.

 

[Greg Corcoran]

My 1992 Ford Taurus SHO has a heating problem and I've tried everything to solve it and nothing has worked. If anyone has had this problem and can help, I'd be grateful.

Here's the problem, when you are driving in the vehicle traffic or when you need to stop the radiador fan starts working when the temperature gauge needle reaches the letter O. And turn off when is in the letter R.
From this point on, it will oscillate between the letter O and R, turning the radiator fan on and off. The temperature only drops a little if I drive at a higher speed.

In this car, the radiator and water pump have already been replaced. The radiator cap, the thermostatic valve, ETC sensor and the temperature gauge sensor (all new) and original Motorcraft, but the problem has never been solved, persisting for 2 years. I don't drive the car much.
I've tried the procedure to remove air from the cooling system several times, but nothing changes. I've already replaced the instrument panel and hoses and I can't solve it.
There is no water leaking at any point. I have already done the pressure test and also bypassed the heater. I have also checked the signal on the sensors and everything is normal. However, the indicator pointer works high and oscillates. This is not normal.
I have attached a photo of the temperature indicator.
If anyone has any information about this problem, I would appreciate it.

I have a '95 - runs that way all the time top of O to middle of R. It's normal for my car. If the fan is cycling you're fine. My '92 ran at a lower place, but was always the same lower place.
When needle leaves its "normal" place for that car is when you have an issue. I had an issue where the ECT (coolant temp sensor that fed the computer) shifted about 40 deg low and the fan wouldn't turn on. Then the needle it went above N if I was sitting in traffic. Took forever to figure that out.

 

[FastCAD]

I have a '95 - runs that way all the time top of O to middle of R. It's normal for my car. If the fan is cycling you're fine. My '92 ran at a lower place, but was always the same lower place.
When needle leaves its "normal" place for that car is when you have an issue. I had an issue where the ECT (coolant temp sensor that fed the computer) shifted about 40 deg low and the fan wouldn't turn on. Then the needle it went above N if I was sitting in traffic. Took forever to figure that out.

True. I found out about the ECT sensor a long time ago too but when that happens it's usually too late. That's why I installed a failsafe thermo and have been good ever since.
Best to ya.

 

[vladimir]

I have a '95 - runs that way all the time top of O to middle of R. It's normal for my car. If the fan is cycling you're fine. My '92 ran at a lower place, but was always the same lower place.
When needle leaves its "normal" place for that car is when you have an issue. I had an issue where the ECT (coolant temp sensor that fed the computer) shifted about 40 deg low and the fan wouldn't turn on. Then the needle it went above N if I was sitting in traffic. Took forever to figure that out.

Hello Greg.
Your car works almost the same way as mine.

I see that this problem affects many Taurus SHOs and that there is no specific reason for the lack of accuracy of the temperature gauge. I have replaced the ECT sensor 3 times and all of them are original Motorcraft and there was no change in the measurement.The temperature sensor has also been changed several times and nothing changes. I conclude that neither of the two sensors is affecting the signal. I also generated the resistance signal in the wire that goes to the temperature gauge and everything indicates correctly (7,4 and 10 Ohms). In my opinion there is something interfering with the resistance between the temperature sender sensor and the temperature gauge.
Tanks for the feedback.

 

[Irish Pride]

What temperature of thermostat do you use? What're the daily temps where you are?

Answered in post #4

-Chad