924Board.org

924IRL · Joined: 30 Aug 2005 Posts: 8

Hi,
This is my first post here and was wondering if anyone can help me with what appears to be an overheating problem. I have an '83 924 Lux with 75000 miles on the clock. The car seems to be running perfectly well. It's used no oil in 2000 miles but when I get stuck in a traffic jam the temp needle runs into the red and it's only then that the fan operates which brings it down to 3/4. There is no other sign of overheating (no steam etc) I've only had to top up the rad once. When driving on the motorway etc the temp gauge stays just under the halfway mark. I'm hoping someone can shed some light on this. Thanks

Ozzie · Posted: Thu Sep 22, 2005 6:50 am Post subject:

That appears to be a little high.
It could just be the guage.
However, you would have to get a temp reading separate from the guage using a thermometer to check.
You could replace the thermo switch on the radiator or the thermostat if you are worried. Both are reasonably cheap.
(compared to a new motor)
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

My solution to the exact same problem (my car never runs above the fist mark on the temperature gauge now):

1: Replaced thermostat with 71C thermostat. Turns out the thermostat that came with the car when I bough it was broken anyway, the lower portion had snapped off the upper portion, it came out of the housing in two pieces.

2: Replaced thermo switch with 65-60C switch. Thermo switch is located on the back of the rad near the top on the driver side. Very easy to replace with the correct size wrench (30mm I think).

3: Bleed the coolant system. You never know, you may have a lot of air bubbles running around in there which can spike your temperature. Plus, bleeding the coolant system will let you know if your water pump is moving any coolant, or if it is broken.

4: Add a bottle of water wetter when steps 1 through 3 are OK. Water Wetter is the K&N Air Filter of the coolant system in that it may not help at all. I don't know if it actually does anything, but I certainly hope so because it is a little pricey.
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1987 951 - M193 Version for Japan

924IRL · Joined: 30 Aug 2005 Posts: 8

Thanks for the reply's. It's very annoying sitting in traffic watching the guage all the time. I'll try your suggestions tomorrow. I'll try following the Haynes manual. The cooling system and also the electrics are the only areas I haven't had much experience of working on yet.

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

Are both fans working?
_________________
John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

Smoothie · Posted: Thu Sep 22, 2005 10:21 am Post subject:

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Water Wetter works! !

It isn;t a magic cure for engines in poor condition, and it won't replace normal maintenance.

What it will do is help a properly working cooling system in good condition to transfer the heat it is carrying.

If I remember correctly, what it does is help improve the transfer of heat from one medium to another by improving the surface contact (and thus the heat transfer).

An example would be placing your hand in a 300 degree oven to pull out a plate. Reaching in bare handed, you can momentarily stand the heat on your hand. But you can't grab the plate because the direct contact between your hand and the plate transfers the heat more efficiently than the air in the oven.

Water Wetter works the same way. It makes for better contact and better heat transfer between the coolant and the components that it touches. Meaning that coolant picks up heat better from the parts of the engine that it is trying to cool, and transfers the heat more efficiently when it gets to the radiator to get rid of it.

On my 81 924, when I bought it, the engine ran at the 3/4 mark normally, rising to the red mark on a hot day, and over the red mark on a hot day, with the ac on. With Water Wetter, VW coolant, a cooler thermofan switch and cooler thermostat, Water Wetter dropped the measured temperature on the gauge to read at the 1/4 mark on normal days, the 1/2 mark on hot days, and the 3/4 mark on hot days with the ac on.

Smoothie · Posted: Fri Sep 23, 2005 4:48 am Post subject:

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

I didn't do everything at once.

My cars have all run VW coolant since I have owned them, so all temperature observations include the same coolant.

The thermofan switch and thermostat were done right after I got the car, as the thermofan switch was defective when I got the car from the 2nd owner.

Those changes yielded a 1 mark improvement.

The second mark of improvement is due primarily to the Water Wetter.

I only added half a bottle at first, because that should have been enough according to the table printed on the bottle. The other 1/2 bottle went into my previous daily driver 87 Ford Taurus Wagon with 3.0L V6. The coomling system on Ford Taurus and Mercury Sable same to run under a higher pressure and temp than any other car I have ever owned. The only water hoses that I have been able to get to last more than a year are the Genuine Ford Hoses, and NAPA hoses. Everything else seems to rupture between 10 and 12 months. The Water Wetter made a more dramatic improvement in the Ford. Before I added Water Wetter the car ran hotter and puked coolant during the summer on a regular basis. After Water Wetter, hoses last longer, the coolant temp was slower, and it stopped puking coolant.

As I wrote before, Water Wetter will not fix a defective engine or poor design. It may allow you to limp by. If your cooling system is in good shape, then it will help the cooling system become more efficient.

924IRL · Joined: 30 Aug 2005 Posts: 8

Thanks for your help guys. I bought a new thermo switch today and will fit it tomorrow. I have noticed a whirring or whining noise coming from underneath the car around the petrol tank area while the engine is running. Could this be the fuel pump? Is this bad?

Ozzie · Posted: Fri Sep 23, 2005 7:14 am Post subject:

I wish mine was that quiet. It buzzes a little as well.
When they get real noisy- get money.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

924IRL · Joined: 30 Aug 2005 Posts: 8

Great! I thought it was about to let me down completely. So it should be ok for the moment? It only started making any noise today.

924IRL · Joined: 30 Aug 2005 Posts: 8

Great! I thought it was about to let me down completely. So it should be ok for the moment? It only started making any noise today.

ATL_racer · Joined: 09 Aug 2005 Posts: 97 Location: Atlanta, GA USA

i have a very similar problem. I replaced my thermostat and water pump a couple weeks ago and im still running hot, my car goes up one mark if i sit at a light for more than 1 min. And i too hate the feeling of staring at my temp guage.

what i did find out was that one of my fans is not turning on. Make sure you check that, im going to fix mine this weekend and probably buy some water wetter while im at it.

Thanx for the advice
_________________
late 1979 porche 924, red 2.0l NA 5speed snailshell
Plans: Restore exterior, revitalize interior, install killer sound system, run engine in stock form and have fun.(+ a short throw shifter if i can find one)