Need an overheating expert/master

[BeatDaSHO]

Well I did get that prestone flush kit where you hook a hose up to the heater core line and flush everything out. I did that for about 15 mins or so and I did it about 5 times. No change. I haven't tried bypassing my heatercore but my heat works great so I don't think it's clogged or anything. I am out of ideas.

Greg

 

[drdave]

You say you changed everything, but I have seen no mention of replacing the fan. Once upon a time in my 90, I had a similar problem. I was convinced it couldn't be the fan, cause it was working, and seemed to be working correctly.

But one day I threw the fan from my 93 MTX in there, and the temp stayed great. Could be worth looking at.

 

[SHOZ123]

The fan shouldn't come on before 215F per OEM programming.

 

[charliejon]

Mine did the same thing. But I had to replace the heater control motor, and since I was in there I did the heater core. Not one problem since.

 

[BeatDaSHO]

With the fan relay i put in, it keeps the fan on A LOT more than normal. It kicks the fan on at a certain temperature. One day I even tried just keeping the fan on and the temp would not go below 195. If i'm cruising on the highway, the temp will not go below 195. This is around the R and M on the gauge. I used to run around the L at all times no matter where I was.

Greg

 

[91SHOInterceptor]

The Fan assembly was replaced about a year ago. It blows towards the motor. Both oil sensors were replaced. Both temp sensors were replaced as well. The fan kicks on at about the "O". The heater core was replaced 2 years ago. The radiator is only 4 months old and is double core radiator. I made some mods to adapter the ATX reserve coolant tank since the MTX one would not fit.

I havent recharged my A/C yet after the rebuild so I wont be able to test it yet with the A/C moving.

I am waiting for my tax refund check to get guages for the car. I should have some time this weekend to do some tests. Compression was checked in all 6 during the initial startup to troubleshoot the engine not turning over. This was due to a bad ECM not opening the fuel injectors that somehow got damaged during rebuild.

I have driven the car over 4 hours at a time on the highway with no problem as long as I keep going. Its been rough and annoying since I have done alot of what has been suggested. As soon as I get guages I plan on installing them to get more info.

The cars performace itself is great put Id rather not push it too much until I solve this plaguing problem. Plus even though I checked the engine mounts it feels like the engine wants to leap out of the car at times when I slam on the gas.

Maybe I just need another set of eyes to look at something I might have missed. Thanks again.

 

[91SHOInterceptor]

What about having a mixture that is too lean? I know that can cause the engine to run hot. Since I replaced the ECM ... could that be a problem? Is there a way to test that theory? AND ... how can it be fixed? LPM?

 

[rbjb99]

Whats the verdict here? did it get fixed.
I have a similar problem.