Bill 86.5 928s

Hello Ernest...Have you tried a leakdown test or pressure test of your cooling system?...Have you noticed anything unusual in your coolant or having to add periodically...Yes...I'm thinking maybe a slow leaking head gasket....but you probably already checked for that....right?... I thought so. Good-luck

Bill

ErnestSw

Glen,
I understand, but if the valve were stuck open I'd have heat all the time wouldn't I?
I've actually seen the heater trick work in my 73 BMW Bavaria. I was stuck in traffic and the car started to overheat. I turned on the heater full blast and the temp came back down.

ErnestSw

Steve,
The belly pan is actually supposed to help with cooling.
Bill,
No coolant level problems, no white smoke. Please don't use foul language like "head gasket"! (:-)

ErnestSw

T_Max has suggested drilling the thermostat. Anybody have any wise comments?

GlenL

Don't like the thermostat idea. If you suspect it, might as well put (another) new one in.

Wild hairs:

Belt slipping at water pump.

Impeller slipping on shaft. (putting a fiver on this.)

Crap clogging A/C condensor.

If the heater valve was open with the mix doors shut, you might not notice.

jpitman2

We get high ambients down here in Oz, and I was told the front shield(between pan and front cross member/radiator) is the only one that should be kept on if high temps are experienced. All the others should go. Doesnt apply to me, but the S4s need to do it.
jp 83

Susan K Thomas

There are some things I didn't see mentioned which you might want to check: 1) is your lower front spoiler atttached? it makes a diffierence in the cooling airflow; 2)if your louvers aren't fully open, it could reduce your cooling airflow - the later cars deleted those altogether, so you could break them out of your radiator opening if there's any question about whether they're fully opened; 3) since you've just changed the water pump, someone's seen the recess in the front of the block where the water pump impeller rides - if the recess is scored from a previous water pump bearing failure with a metal impeller water pump (sold in the rebuilt market but not orginally found on the post-'88 cars) then you've diminished water flow throughout your cooling system; and 4) you might want to check to see if your AC heat exchanger in front of the radiator is loaded up with sand or grit that might be restricting airflow to your radiator.

reno928s

Ernest, I can't believe it didn't work. Did you install the lower degree thermostat? I changed it in my car and it made a big difference along with the cooler running fan switch. Was your car always running hot or did it happen after the TB and water pump change? Reno

ErnestSw

Susan,
Thanks for the suggestions.
Let me first say that the Devek radiator is a beautiful piece of work with ALL mig welded seams. The radiator itself is actually running nice and cool and the temperature readings are impressive. Unfortunately, that's NOT translating to a cooler engine in my case.
!) The front spoiler is attached and I have full belly pans.
2) The louvers were discontinued in 91 and my car doesn't have any.
3) The front of the engine looked fine when I replaced the water pump.
4) Even before I installed the Devek radiator I'd cleaned out the recess behind the AC condenser.
At least, with the Devek radiator, I have the peace of mind knowing that the radiator is no longer in question.
I just wish I could figure out why the @#%%$@$ thing is running hot AND pinging!!

Reno,
I haven't changed to a cooler thermostat---yet. And the car ran hot on Texas Motor Speedway the first hot day I ran it, before the TB change.
I'm having a hard time understanding why a 75 degree thermostat would make the car run cooler. It seems to me that the heat load would be the same, just take longer to build up. I'm also wondering whether the little hole at the top of the 75 degree thermostat has anything to do with it.

Gregg K

Ernest,
Could it be running lean? Pinging sounds like it could be too lean.
Pinging huh? Can you elaborate? When does it ping? Could it be getting too much advance? I think you mentioned it was right on the timing mark, tho.
I wish you patience. I have empathy for your situation, as I've been through these kinds of problems so many times. Hope we can solve this before you go nuts.
Hey, I just lost $1200. It sucks.

PorKen

O2 sensor?
Plugged cats?
Fuel pressure?
Knock sensor?
Temp sensor values?
Incorrect spark plugs?

I'm thinking it's a fuel/timing issue.

reno928s

Ernest, my car has not reached the top white line since I changed to the cooler running thermostat. I figure the thermostat stays open longer bringing in cooler antifreeze. The last thing could be a bad sensor the one that gives your gauge the reading. Reno

Steve J.

Did the problem appear suddenly or gradually over time? If suddenly, what changed? Is the problem with the engine or the cooling system? (Is the cooling system undercooling or is the engine abnormally overheating?) Air flow or coolant flow problem? What possibilities can you eliminate? Maybe you can fix it by figuring out what the problem ISN'T.

PorKen

That would be funny if it was just the dash temp sensor or gauge...

What was the temperature of the engine outlet/radiator inlet hose(going to the top of the radiator)?

ErnestSw

I'm open to all suggestions at this point. The cats show good vacuum at 4000 RPM and it climbs with further accelleration. The knock sensors are new. The gauge reading is in sync with the thermistor readings. The outpot temp to the radiator is about 210 degrees and the input temps are about 200.
I've just installed the 75 degree thermostat and we'll see what happens tomorrow after I get some more coolant and distilled water.
Tip of the day----buy Prestone stock!!
Could incorrect spark plugs make the car run hot?

Steve,
Airflow and radiator have been pretty well checked. I'm leaning towards an engine overheating problem or an inadequate flow of coolant to the radiator.