924Board.org

[James C]

Obviously because I want to sell it, something has to break.

My '81 924 has just had a new radiator and thermostat put in, new coolant rah rah rah.

Now, before the radiator was put in, it held temperature quite well. The bottom of the radiator was mostly rust so I had the whole thing replaced along with the thermostat for good measure. Now, the thing overheats and pisses coolant out the overflow if it's idling for too long. It's fine when it's moving again. Needless to say this is a real shit feature in traffic.

I'm thinking water pump is going or gone - What does the rest of the board think?

NB, I'm probably not going to fix it, rather sell it as is - I just want to know what the issue is.
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Sorry what? I couldn't hear you over my pop-up headlights.

[Brians924]

You havent said that the fan is working... 2 things need to happen when the temp is getting there. Both require the fan to engage.

B.
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1977 Porsche 924 n/a
2.0 4sp. w/59k

[James C]

The fan does go. Sometimes it stays on after everything else is shut off.
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Sorry what? I couldn't hear you over my pop-up headlights.

[Duncan]

Are you sure the cooling system is bled properly as per the red stopper on the hose from the thermostat housing?
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1983 NA Alpineweiss since 2001
Peugeot 205 Generation

[staticsan]

If the water pump stops, you'll get about half-a-mile before it will burst a hose. Been there, done that.

HTH!

Wade.
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'82 British NA - Which I think I've been very lucky with!

[fiat22turbo]

Bleed the coolant and see if that improves things.

If not, I suspect you've got a blown headgasket.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[James C]

[fiat22turbo]

A blown headgasket doesn't always result in oil and water mixture. There are times when it only results in combustion pressure leaking into the cooling system, over pressurizing the system and causing the fluid to be pushed out of the system. Sometimes you can see this on the spark plugs by seeing which ones are sparkling white (due to steam cleaning of the combustion chamber)

If you see bubbles in the coolant once it starts to warm up (start the car cold, take off the radiator cap and keep an eye on it as it warms up and watch for bubbles) then you might have a leaking or blown headgasket.

To bleed the system, park the nose in the air, start the car cold, remove the red bleed cap. Once the car warms up water will start coming out the bleed port. Once water starts coming out, put the cap back in and tighten the clamp. You may have to do this a couple of times, especially after cycling the heater on/off to flush any air out of there as well.

Good luck!
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[James C]

[Ozzie]

I had a blown head gasket between 3 & 4, no pressurizing of water, no mix of oil or water, just air pumping back and forth.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[pmcaya2]

Since the car was OK before you replaced the radiator & thermostat, I suspect that the new thermostat may be defective or fouled by rust - maybe even installed upside down. I'd spend $5 and put in another thermostat before going after the big stuff. The bolts on the thermostat housing are usually the hard part of installing a thermostat. Good Luck - Peter

[James C]

[Paul]

What temp thermostat and radiator fan switch do you have? Are the fans running the correct direction?
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

[James C]

[Duncan]

No observable change in behavior after bleeding the cooling system?
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1983 NA Alpineweiss since 2001
Peugeot 205 Generation