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Nein37 · Joined: 29 Dec 2009 Posts: 513 Location: New London, CT

I smell coolant on start-up after it sits overnight.

1. Lasts about 30 seconds or so.
2. Its not blowing white smoke, exhaust is perfectly clean and doesn't smell of coolant.
3. The oil looks perfect
4. The coolant looks perfect
5. Coolant tank doesn't get pressurized while running.
6. Pulled the plugs and none of them look steam cleaned.
7. Car is running very good, makes plenty of power and holds boost.

My only concern is that during my tuning I had some pinging, and while it didn't appear to affect the plugs its quite possible the head gasket took some abuse.

However, I'm hoping its something to do with the cooling system itself leaking a bit... but I see no puddles and the amount I'm losing must be very small since I haven't noticed the coolant level dropping.

Kinda stumped and don't wanna pull the head off if I don't have to. Any thoughts?

Maybe I should just re-torque the head bolts and see what happens?

Nein37
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1981 931 CGT replica, OEM CGT intercooler, .8 BAR WG spring, GTS Headlights, Innovative Wide band A/F, A/C delete, 16" Fuchs, Weltmeister 200lb lowering springs, Bilstein HDs front, Koni Sport rears.

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

See if you can borrow a coolant pressure testing kit and pressurize the coolant.

There is also a UV dye system you can use in the coolant to detect leaks.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

I would retighten all your hose clamps carrying coolant as a first step.

If the smell remains, I would consider replacing the coolant cap.

If the smell still remains, I would suspect the heater core, if original.

If it is the heater core, you are extremely lucky. Removing the dash and HVAC unit from my 931 was one of the most pleasant, and relaxing tasks I have ever done.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

+1 on the heater core. If you're smelling coolant from inside the cabin, the heater core is the first thing I would suspect.

It is possible to replace the heater core without removing the dash if you don't have A/C. If you DO have A/C, it is still possible, but NOT easy to do without damaging the core.
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erstwhile owner of just about every 924 variant ever made

Nein37 · Joined: 29 Dec 2009 Posts: 513 Location: New London, CT

Engine bay AC components have been removed but I still need to get the under dash stuff. Its curious that it only smells for a 30 seconds or so. Any ideas on why?
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1981 931 CGT replica, OEM CGT intercooler, .8 BAR WG spring, GTS Headlights, Innovative Wide band A/F, A/C delete, 16" Fuchs, Weltmeister 200lb lowering springs, Bilstein HDs front, Koni Sport rears.

Nein37 · Joined: 29 Dec 2009 Posts: 513 Location: New London, CT

Fifty50Plus · Posted: Wed Nov 28, 2012 9:12 am Post subject:

Was the heater core leaking? It's almost worthwhile being all contorted and upside down if you solved the problem. Then again.......
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1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA

Nein37 · Joined: 29 Dec 2009 Posts: 513 Location: New London, CT

I hadn't smelled a problem for a long time but it was on my list... for a second I almost put it off again, but I've got the intake manny off, so now was as good a time as any.

If the old unit was leaking it was very minor and may have clogged up, if that was the case it needed to be changed just in case.
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1981 931 CGT replica, OEM CGT intercooler, .8 BAR WG spring, GTS Headlights, Innovative Wide band A/F, A/C delete, 16" Fuchs, Weltmeister 200lb lowering springs, Bilstein HDs front, Koni Sport rears.