overheating

[onrails]

new water pump (106.124.3R),new thermostat tested, belt tension good, interior heat good, spent two days checking for air in system, heater on, even on an incline, tested fans with "Clark's", and they work high, low, and a/c, but they don't come on.... ever, when hooked up and engine running HOT or cold, radiator is cold, lower hose is cold, upper is hot, but the thermostat looked fine in that pot of water. exhaust looks good no smell, oil press. good, still cant feel any flow when i squeeze the upper hose. water pump impeller shaft is not slipping on the outside, (marked it) can the impeller come off inside? i don't know. would hate to do all that again for a peek. the car runs as good as ever, plenty of power, until it hits red and comes out the reservoir cap. Any new ideas will keep me from fetching my tools from the street every 2 hours, and i would very much appreciate it

[smokin_944]

Have you done Clark's troubleshooting? There is no mention of relays or even the thermal fan switch mounted in the rad. When you say the fans run high and low and with A/C do you mean in testing mode? What year is your car? Early and late cooling systems operate somewhat differently.

[Mark944na86]

Sounds to me like you've still got air in there.

[ernie9944]

Originally Posted by Mark944na86

Sounds to me like you've still got air in there.

+1 on that.

[onrails]

its an 87' 944S. i did do clark's for the fan t-shooting, and they work in test mode as well as with the car running and a/c on, but it didnt seem clear to me if they should come on with the car or when the thermal switch sees heat.
I sure hope its air, but i cant help to think i lost my touch being my third 944. will a pressure filler work on the reservior to force air out if i manuall open the h-core vaccume controle? or is an inclined drive all i should need, its fairly steep, took three people to push it up in the garage.

[taki951]

Hi I work on these all the time if the top hose is hot and the bottom is cold you need a radiator take it out turn it on its side and put water thru it from the top hose if brown crap comes out replace it

[onrails]

I did manage to makeshift a garden hose flush to the top radiator hose. The water seemded clear and flowed as fast as the water went in. Is it a must to have it on it's side? It's not just running hot it's headin to the max. But I'll look up how to remove the radiator with Clark's. Thanks

[onrails]

Wow, my typing sucks. Or maybe it's my letter learnin'

[taki951]

Yea you have to turn it on its side or the crap wont come out if you have any brown stuff come out get a new one there is no way to fully clean them out Pete

[onrails]

Pullin the radiator shouldn't take too long, it's only water at this point. I'll give it a look. Thanks

[Mark944na86]

Originally Posted by taki951

Hi I work on these all the time if the top hose is hot and the bottom is cold you need a radiator

Or you have air in there.

I wouldn't pull the radiator unless you knew you had to; they aren't the most robust design, and you may end up needing a new one after pulling it, even if you didn't before.

[onrails]

Ya, been two days on the air issue. Was gonna give it one more day of effort before I pull the radiator

[Grandad#3]

If your radiator fan does not come on by itself on low, and the motor checks good, replace the thermo switch on the radiator. Use steady even pressure when turning it out or you will strip out the plastic threads. Order a new switch and gasket. Where did you buy the thermostat? I will only use a Wahler made one. The ones from LAPH need a spacer.

Cheers,
Larry

[taki951]

Originally Posted by Mark944na86

Or you have air in there.

I wouldn't pull the radiator unless you knew you had to; they aren't the most robust design, and you may end up needing a new one after pulling it, even if you didn't before.

If it has crap in it you will never get all the air out and the fan switch is at the top of the radiator right where the air pocket sits I have even taken out the switch and bled the radiator from the switch hole and still had them overheat when the are bad. How old is the radiator?? Another way to get the air out 100% is to use a tool called an AIR LIFT if you can get your hands on one to bleed the system use it and after you verify the radiator is good or bad.

[onrails]

The radiator is original I assume. But still the question is, are the fans supose to come on low when u start the engine, and high when it heats up. I'll look in Clarks for th-switch test. And I'm still gonna try the air thing again before that and maybe pulling the rad.

[jbaeng]

I used a pressure pump you can borrow from Autozone to pump ALL air out of the vent. One time and all the air was out. First time I replaced my timing belt and water pump, I was chasing air forever out of the cooling system until I tried the pressure pump attached to the reservoir. also used the same pump and found my cap was bad as well.

[onrails]

Good to know it accualy works, you can't always rely on the kids at the local parts chains. I'll be tryin that this eavening. One question. Will it pressurize past the closed thermostat and heater valve? Guess what I'm trying to say is should it be running with the heat on and/or thermostat open?

[Rasta Monsta]

Had this problem with the Chump car, on a brand new thermostat. The cold radiator is a clue that the t-stat isn't opening. Many people have had trouble with generic t-stats sticking, even new. Get a Porsche unit.

[onrails]

Wholly #%}*+, there was a lot of crap came out of this radiator!! It's still in a liquid form. Gonna get som quotes on a new radiator tommorow. But I might mess with flushing this one out tonight. What can it hurt, but of couse wouldn't drive it past the 1st mark on the gauge in distance.

[mattdavis11]

I have one that was only in the car a couple of months, but I had to patch it after it caught a rock. It's unfortunate, but it was leak free when removed. I'm not not going to do anything with it as I now sell AC and Radiators. I'll probably core it out and sell the aluminum, but if you want it...