84' 944 running too hot?

Timothy · 10-26-2002, 02:56 PM

I have an 84' 944 with 120k miles on it. It seems to run hot all the time and has overheated a few times. The over heating seems to be random; somtimes in traffic sometimes on the open road at highway speeds. The other night I got it up to 115 MPH for about 4 miles and it didnt overheat at all! What gives? I've had the cooling system flushed recently, but nothing else. The temp needle is almost always on the third line if not over when the engine is done warming up. A few times it has gone into the solid yellow square. Does that mean its about to blow? Should I jump out and roll if that happens? Any advice from fellow owners?
My other question is how fast could the early 944 get up to when it was new with all original stock? 140 maybe?

Lawrence Coppari · 10-26-2002, 03:11 PM

It could be a number of things. A sticking thermostat or air in the cylinder head are two possibilities that come to mind first. You can bleed the system to get the air out. Replacing the thermostat is a little more fun. You'll get introduced to the snap ring of your dreams.

If your's is like a turbo, the back of the cam belt drives the water pump. Does you waterpump make strange sounds?

You could also have a plugged radiator.

Are your electric fans coming on? Are they turning in the correct direction when they come on?

Goku · Goku's Garage

Don't let your car overheat. These are all aluminum engines. These aren't chevy's that you just overheat..wait a while and then it's fine, these engines can get serious damage from overheating. If you see it starting, pull over like the oil light just came on!

todwic · todwic's Garage

Quote:

Originally posted by Goku
Don't let your car overheat. These are all aluminum engines. These aren't chevy's that you just overheat..wait a while and then it's fine, these engines can get serious damage from overheating. If you see it starting, pull over like the oil light just came on!

DO NOT, REPEAT, DO NOT LET THE GAUGE GO INTO THE YELLOW!!! NEVER UNDER NO SURCUMSTANCES, NOT EVEN FOR A LITTLE WHILE!!!!Look here for the stuff I did to my car, and other information.

Timothy · 10-27-2002, 01:03 AM

I thought about a sticking thermostat. That could be it. The few times it did get up to the yellow I pulled over and opened the hood. It didnt feel too hot ( yes I actually put my hand on a possibly overheated engine). Could the gauge be wrong?

divezic · divezic's Garage

Search this BBS. There are a lot of good discussions of overheating.

If your car is overheating in traffic and on the highway it's probably the thermostat stuck partially closed, air in your system or a clogged radiator.

Mine happened to be a clogged radiator. I diagnosed this by heating up the engine, turning off the car, disconnecting the fan electrical plugs (for safety), and feeling the radiator. Only the bottom 1/3 of the radiator was hot. The top 2/3 was cold. A new radiator later and the problem was solved.

Bad thing: a new radiator is $250-$300
Good thing: it's easier to replace the radiator than the %$&%$ thermostat. But while the system is apart, change the thermostat anyways. Also, put in a new thermo fan switch. Don't forget to bleed the system of air when you are done. Again, this is described several times in this BBS. Just do a search.

Cebu · 10-27-2002, 11:43 AM

Just my experience to solve a high temp problrm (3/4 mark and higher)..I replaced the radiator, thermoswitch, and installed a lower temp thermostat. The ultimate solution was replacing the COOLING FAN RELAY, which was functioning properly intermittently. 86 944na.

Roadman_944 · 10-27-2002, 01:36 PM

I own an 83 944 and also had the same problem. Exactly!!! I found the fan relay was the cause. My fan starts when gauge is at the center mark and off when at the first mark. Maybe you can use this for referance. Good luck.

mike944 · 10-27-2002, 01:53 PM

It's probably air in the cooling system, it's fairly common if the system is partially or fully drained and not refilled acording to the proper procedures.

You say you recently got the cooling system flushed, did you do this yourself, or did you take to somebody? If you took it to somebody, was that person familiar with 944's or did you take it to some quicky-lube place? (cringe)

Here's how to bleed the system: Follow the upper radiator hose until where it meets the engine. Loosen the bolt shown, (you don't have to remove it) and pour coolant into the coolant resevoir until you see coolant coming out from under the bolt. Warning: this may take a while. Tighten everything back down, and your problem should go away.

Mike

P.s. you did tell them to use phosphate free coolant, right?

divezic · divezic's Garage

If it's overheating on the highway then it's probably not the fans or fan relay.

todwic · todwic's Garage

Try this site if you think you temp gauge might be buggy.

Also, when you bleen the system, jack the front end up about a foot, or do it on an incline.

Roadman_944 · 10-27-2002, 05:10 PM

This is how I found my bad relay. It may or may not help you but it worked for me. I started the engine and idled it until it reached the temp. where I knew the fan should start. When it did not I shut the engine off and checked the fan motor leads. Seemed ok. I then restarted and turned the AC on. I heard the fan start. I then looked in the wonderfull manual Porsche provides for possible clues. Being my first vehicle with elec. cooling fans I was not aware that they were fused and had a relay. I checked the fuse and it was ok. I then pushed the relay and found it loose. I restarted the engine and the fan has started and worked since. I am still not sure why the AC turned on the fan when the relay was loose. The AC has a condensor fan. Are they controled seperate? Maybe that is what I heard and got lucky with finding the relay.

FYI.
On my 83.
Fan fuse is in top block. Third from left.
Relay is top row first on left.

todwic · todwic's Garage

When you turn the A/C on, both fans come on. It's probably on a different circuit, tho I don't know that for sure.