924Board.org

[Knz]

I picked up my 1980 turbo this past Saturday, and it sure is a lovely machine. I'm told its all original, and with 62k on a working odometer, I think I can believe it. I have yet to look over the paperwork that came with the car.

My one question is, I noticed that sitting in idle the car would start overheating. I'm drawn to think it might be an issue with the cooling fans, but honestly I just haven't had the time to check. The whole time I was driving the car home on Saturday, the temp gauge remained below 1/4! I'm hoping to get a chance to get under the hood later this week, but for now she's patiently waiting while I arrange a more permanent location for her.



you can see my dd hiding in the background
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1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

[jason c]

Cool. Welcome. Got more pics?

[Knz]

only a few for now..







sorry, the engine one is a bit shakey, I'll try and take some more pics tomrrow
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1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

[Rasta Monsta]

Welcome!
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[pcelenta]

Welcome! Sharp car!
Re: overheating is way bad. Check that your fans are running. When it's hot turn car off and put key to first position. You should hear the fans running. Also. Real easy to jump the switch at the top of the radiator to test or if you are in traffic and in a pinch.

[Knz]

[pcelenta]

cooling system may also need to be bled...pretty simple procedure to do. might have an air pocket causing the problem.

[ideola]

Disconnect the leads at the temp switch, which is at the top of the rad. Make a jumper and connect the two leads. Put the key into the ignition, do not turn. Both fans should run. If both fans do not run, the temp switch is bad. If only one fan runs, check for blown fuses. If no blown fuses, then there is either a fault in the wiring, or the non-functioning fan is toast. Incidentally, with those connections jumpered and no key in, the low fan speed circuit should activate the LHS fan only at low speed.

If all that checks out, then the problem is more likely to be an issue with coolant circulation: bad or failing water pump, clogged radiator, clogged heater core, stuck thermostat, or air in the system. There is also a possibility of a blown head gasket, but let's not get too worried about that just yet.

Since nobody has said it yet, I'll be the first to recommend changing the timing belt and tensioner immediately. While you have those items off, you might consider just going ahead and replacing water pump, the thermostat, and the fan switch. The car should not be overheating in the winter, even while idling. But in the summer, you may find that changing the thermostat and fan switch (they should be matched) to a lower temperature pair will keep the engine running nice and cool.

At a minimum, in addition to changing the timing belt / tensioner, you should definitely plan to drain and flush the coolant. You should run the orange stuff, not the green stuff. I highly recommend a 50:50 water:glycol mix in northern climes. You can get away with 60:40 water:glycol in summer (water runs cooler than glycol), but I wouldn't risk it in the winter, especially THIS winter. Also, add a bottle of Redline WaterWetter. When you flush and bleed the system, don't forget to ensure that the heater core is fully open. Don't rely on the levers in the car, double check the heater control valve to make sure it isn't stuck, or that the Bowden cable hasn't bent or disconnected from the control arm.
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erstwhile owner of just about every 924 variant ever made

[Knz]

Thanks for all the advice everyone!

I have the car parked in my storage unit and havent had a chance to do anything, going to flush the coolant today however.

As to the timing belt and tensioner, the previous owner had (almost) all the paperwork of maintenance to the car since new (super awesome!!) and his records show that there qas a full tune up, including timing belt, sparkplugs, oil et cetera performed not even 1000 miles ago, albeit that was almost a year and a half back, would the belt and tesioner still need replacement?

I am looking inot getting the water pump and temp switch thru your site ideola, one (probably dumb) question tho.. Are all those water pumps in those package deals new or refurb? And are they OEM?

I brought my multi-meter with me and im going to troubleshoot this cooling issue on the electrical side too.

Oh one last question while I have your attention, are the relays interchangeablr between the 924 and the 931, particularly the fan relays? I have a bunch of spare random relays back fron when i owned a 924 na and i was wondering if there was any point innholding on to them any longer.

Thanks again!
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1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

[ideola]

Timing belt and tensioner should be fine if they only have 1000 miles on them. The only concern I would have would be corrosion in the timing belt tensioner if the car has not been run in a while. If you hear any strange squeaking from that area, then I would replace it immediately.

The water pumps are NEW, not refurbed. They are manufactured by GEBA, an OEM supplier to Porsche (Porsche do not make their own water pumps for the 2.0L cars).

Regarding the relays, it really depends on what specific function. For example, the fuel pump relays are different; but almost all of the other relays are cross over between NA and 931. The bigger issues is more model year, as the early cars (pre 1979) sometimes had different circuits (like the headlight lifting motor, for example).

Bottom line, hang onto ALL the old stuff you have. If you can't use it on the 931, you might be able to trade it for stuff you can.
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erstwhile owner of just about every 924 variant ever made

[Knz]

Might be another dumb question, but where is the bleed screw on the 924 turbo? I can see a screw in the top of tye thermostat, but thats it...
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1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

[fiat22turbo]

That's the only bleed screw in the cooling system.

There is a drain plug in the bottom of the radiator on the right side (when looking down from the nose of the car)
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[Knz]

Yeah, I drained the coolant, but was unsure of how I would go about bleeding the air out of the system when refilling it. I think these directions in the haynes manual are focused on the N/A. Would I then use the screw / bolt in the thermostat to let the air out of the system?
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1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

[fiat22turbo]

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

[pcelenta]

be sure your heat is put in the on position and that your heater valve is actually open (easy to check in the engine bay)....then bleed away!