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Operating Temperature

Car:

1986 Porsche 944 Non turbo 102,000 miles Major Service done at 80,000 miles T-Belt re-tightened 600 miles ago

Problem:

When fully warm the water temp gauge would be passed the middle, almost up to the 3/4 white dash. This is when on the highway, when in town it seems to drop down into the 1/2 way range. But mostly stays around 3/4 or just a little below. Last night driving home, it hit the 3/4 mark on the highway and then as I was passing through town it dropped quite a bit down to the

1st white mark, or about 1/4. (Sorry I dont know what else to call the marks on the water temperature gauge). I've never seen it drop this low while driving, especially when its been running hot. Is this a problem with my gauge, thermostat, maybe some gunk around the radiator? I have no idea, but it bothers me driving down the highway with a car that is running past halfway on the temp guage. Although so far it has expressed no signs of over heating or malfunction.

Thanks.

Reply to
Gary Lehman
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Gary, Typically the temp gauge stays at 1/4 on the freeway and may jump up to

3/4 in traffic. The fans will then kick on at that time and drop you back down to 1/4.

I would give her the old flush and refill first. You could be running on old antifreeze. You may clear up a clogged radiator, etc...

Reply to
Devils944

putting in a chevy V8 sure would be cheaper than putting in a new water pump boy, and it would be fster too. LOL

Reply to
Jizztec

Make sure that all air has been properly bled out of the cooling system. If there is any air in the system then the engine can run significantly hotter. It is notoriously difficult to get all the air out even when using the bleeder plug at the top of the radiator housing.

To check for the existence for air, connect a pressure tester to the coolant reservoir and pump up the pressure. If the coolant level goes down, then you've got air in the system (air compresses, coolant does not). You can use the same pressure tester to 'force' the air out through the bleed plug.

Reply to
Proud Yankee

Just a suggestion...

I also own an 86 944 coupe, and my engine temperatures original acted almost identical to yours. Another thing that causes the temps to rise considerably is the A/C. I replaced the thermostat with a lower temp one, added Slick 50 Synthetic and changed the oil grade from 10W/40 to Castrol Synthetic 5W/50. Although synthetic wasn't around when I first started this combo, ever since, my temp gauge maxes at the first bar, and even runs slightly below that during winter temps (well, central Florida winter temps). This applies for both around town and highway trips. I know some people swear against additives, but my experience has been a positive one. Also, I've been using Slick 50 for close to 10 years and my car runs just like it did when it was brand new... even with over 140K miles on it. I'm not saying that Slick 50 had anything to do with this, I'm just saying that it hasn't caused any problems with the car after all these years of use. Oh, I also flush the radiator every Spring so nothing gets cogged.

Hope this helps..

Rip

Reply to
<ripmunsterman

Every engine I have put slick 50 in ultimately died from engine falure due to oil related propbems. When the stuff gets old it turns to glue.

Reply to
C McFaul

Reply to
Brian Moore

Brian's response reminded me of a possiblity. It could very well be that your cooling fan relay is going bad. When it does, it will spuratically turn the cooling fan on and off when it should be on. A good way to tell is by listening to the cooling fan when you turn the car after driving it for a while. If it runs for a bit, stops for a bit and then runs for a bit, you'll know it is going. You will also hear a clicking noise inside the car as the relay clicks on and off while driving, but it's easier to hear it outside of the car with hood raised and the engine off.

However, there is one thing that I can't explain. I didn't pick up on the first time I read the initial post that your highway temps were greater than around town temps. This should be the opposite. As your speed increases more air is naturally being forced through your radiator. Therefore, your cooling fans would play less part in cooling your engine on the highway. Around town when you are sitting at stoplights, etc., your engine is relying

100% on your cooling fans.

Rip

Reply to
<ripmunsterman

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