Overheating - Maybe? IDEAS?
 

If I run my '01 fairly hard the temp gauge does go up to the mark between 180 & 250....not what I would consider to be overheating. But, when I stop... the coolant overflows from the tank like it IS overheating.

Any ideas as to what the cause could be? The Water Pump is not making any noise like it is failing or has failed. I replaced the engine (IMS fail) about 10K miles ago and replaced the Pump & Thermostat then.

Don't want to pull the pump (looks like a P.I.T.A.) if there is something else that I should check first.

Thanks for your input......

Lars

Are you cooling fans working?

I may have been running without the A/C on low. I did that....ran it hard for 30 minutes....temp gauge got up to right between the 8 & the 0 on the 180 mark.....no higher. It was definitely warm when I got home....but the fans in the front were working fine. I was also told that there is a rear fan as well.....where is it located? I heard no fan from the rear of the car.

Rear fan is in underside of decklid and is actuated by a temp sensor clipped into a rubber grommet on the passenger side intake manifold.

Coolant is below the full line? Vent in overflow tank is closed? Maybe make sure the cap is up to the latest revision (996.106.447.04 - the .00 rev in particular is known to fail).

I can't imagine any connection, but maybe also be sure that your radiators aren't blocked with debris. They collect a lot of junk.

Exactly what I was thinking. I would first make sure the expansion tank was fine and had the updated cap. Seems like I remember Raby speaking about a common problem with overheating is blockages like the plastic water pump impellers breaking off in the system.

Debris in the AC condensers, and in the radiators.

Fans working on low and high setting.

Next would be water pump.(it's not fun, but not too bad. A few of the bolts are hard to reach, and the truss in back must be loosenend) Check impeller for loose on shaft, or missing vanes.
The last solution is to replace the thermo with a 160F, and add the center rad kit. Clean rads, working fans, pump, low temp thermo, and center rad and you will never, ever overheat again.

Thanks......
 

Great ideas.... I'm on it. Will let you know what I find.

Thanks,

Lars

It isn't that much of a PITA to change the water pump. I would check the fans and clean out the garbage from the radiator and between the radiator and the condensers.

I think this is what you meant...

Good advice all around. Start with the simple stuff - clean the rads first. Move on from there.

For what it's worth, my coolant level equalizes below the min mark. Any time I add more - it still returns to equalization level.

DOH... Yup, 160F. I was working on my Dodge truck which has a 202F and I put a 180 in that. Got cornfused.

Greetings,

I am very interested in this thread - I recently purchased my '99 and am somewhat concerned about running temps.

Did you install an aftermarket coolant tank when you replaced motor by any chance? I recently replaced my coolant tank with an aftermarket (big mistake) which had bad threads and caused the same problem you describe - could not get the new cap to seal tight. The second tank they sent me is much better, but occasionally I still get a droplet or so of coolant at the base of the cap which is unacceptable to me. There is no question the car ran hotter when I had the defective tank/cap did not seal. Cleaning rads helped as well, even if they look clean from outside there was a ton of gunk between the condensers and rads.

I still feel I run warm. Open highway I stay about 93c which keeps me in the "8"and "0" range for the most part - but any around town driving/traffic I start to creep past the "0" and 105c. First car I have owned where the temp gauge actually moves after completely warm so I find myself staring at it - alot.

I am also doing the water pump (Porsche!!) and low temp thermo very soon, with another (Porsche!!) coolant tank...FYI there is a thread here about one of the popular suppliers having a discount code on parts through Memorial Day

If the warning light doesn't come on for the temperature gauge then don't worry about it. Porsche should have kept this gauge a dummy gauge (always stays in the middle unless there is a problem).

You can do all these things - clean the front rads, change your water pump, change the thermostat, change the cap and tank - and it won’t have much affect on your temps

Here’s why: the gauge is not accurate.

My car would run an apparent 115C before the high speed fans would come on, but the ECU would report an actual 102C, the exact temp the high speed fans are supposed to come on.

If the tank is leaking, sure, that needs to be fixed. But your temps aren’t really connected to leaks unless you are building pressure, and your temps are likely not that high.

Save your money.

Past the zero is probably not 105C. The second line between 180 and 250 would calculate to be close to 110C, but it’s actually closer to 102 on my car. Please check DME readings, not the Audi HVAC panel or dash.

I suspect that happens on the later cars, because 99s have the gauge moving all over the place