924Board.org

[Haven]

Hi all,

My car (87 924S Auto) has been sitting since January, because I don't drive it much in the winter. I also replaced the fuel pump in January and after making sure it worked ok, I parked it until nicer weather.

Recently got the car back out on the road and noticed a new sound. The best way I can explain it is sort of a dry slightly grinding sound. Almost like metal spinning against metal. All of the fluids are fine. Oil pressure reads perfect, car doesn't overheat.

The sound seems to come from the top of the engine somewhere, but I haven't pinpointed it yet.

Just wondered if anyone else has had this problem or a similar one before. Had the car checked out before I parked for approx. 5 months. Timing belt was tightened/checked last year and was still good from replacement earlier.

Any help is appreciated.

Thanks!

-edit- Forgot to mention, the noise goes away after about a mile or two of driving. Sometimes it will re-appear briefly at a stop light, etc., then go away again. After the car has been parked and it has sat and cooled down a little, the sound comes back upon starting it. It doesn't sound like a belt squeak or a rattle.. it sounds like metal rotating against metal. It can be quite loud if the hood is open, but it doesn't seem to affect the car's performance. Got me worried it could be something internal though.
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1987 Porsche 924S Auto

[fiat22turbo]

Could be bad motor mounts causing the exhaust to rub or move, which would be cast iron or old corroded steel rubbing against itself.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[Rasta Monsta]

Most likely is alt bushings or one of the front engine rollers.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Haven]

Thanks guys.

It doesn't sound like an exhaust system clang or rattle, because when it happens it is a continuous noise. But I will check into this.

Could very well be alt bushings or a front engine roller. I hope it's the alt bushings. Sounds like a much easier fix.

With the rollers, I'm assuming I'm looking at FOES again right? I had the timing belt rollers replaced a few years ago when I had the timing belt replaced, and even though I had the timing belt re-tensioned last year and it's in good shape, it's probably due for the FOES anyway. Sort of just figured the rollers would hold up longer than that. I haven't even put 10k miles on the car in the 3 years since first FOES. This thing sees more driveway pavement than anything. If it is a roller... that means parked until fixed correct?

First thing I'll check into is the alt bushings and go from there.

If it's FOES time. I'll be damned if I don't do it myself this time.
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1987 Porsche 924S Auto

[Rasta Monsta]

Do you have the receipt from the prior FOES? There are four rollers. . .unless the service guy sees a pot of gold in your trunk, it is quite unlikely all were changed. Pop off the upper belt cover and fire the motor. If a roller is bad, it should be fairly obvious, especially with a stethoscope.

If it is only an idler, it can be swapped without disturbing the cam and balance shaft timing.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[Fasteddie313]

[Haven]

I still have the receipt. Looks like the only rollers he changed were part numbers: 944-105-631-06 and 944-105-241-04.

I've read several times on here about doing the timing belt etc, and how it's do-able with some mechanical inclination, of which I have, but I've never tackled anything that involved. But, I'm definitely a lot less "scared" of it now.

If it indeed is a roller or an idler, I'm assuming it's not much of an extra PITA to replace these since I'll have everything broken down to that point anyway.

I do have the 6 volume Factory service manual, a Haynes manual, Clarks-Garage and of course you fine gentlemen. So hopefully, between all of that, I can pull it off. Besides, I'm tired of giving money away for something I'm confident I can do, albeit after a lot of cussing and doing things 2-3 times instead of once. But, at least I'll know for sure it was done and done right.

Still going to check the alt bushings this weekend and will go ahead and pull off the upper belt cover and see what I have.

Thanks for the help. Appreciate it.
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1987 Porsche 924S Auto

[Haven]

Just an update:

Was able single out the noise and this ended up being a bad alternator bearing, which is why I was hearing the metal on metal friction sound.

It is bad when started and subsides when driven.

Now in the market to have mine rebuilt or buy a new one.
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1987 Porsche 924S Auto