Garth S

There is a distinctive, metallic 'ringing' noise - with some ticking in the background in the video clip: while I probe the "memory banks" of odd sounds, does your car have an air injection pump? If so, put the stethoscope/screwdriver on the pump, and on the vacuum actuated control valve ( on the hose ~40cm from the pump). In the meantime, I'll listen again .....

Bill Ball

I ran the video clip. I heard rather loud clatter at first, sounding like the oil pressure was low and took a while to pump up. You just did an oil change, right? Maybe you did not fill the oil filter with oil, so you were pumping air for a while.

That seemed to go away but in the background was a more subtle tick and a rather louder clatter still. The louder noise got much more pronounced as you leaned over and reached into the engine compartment. Did the microphone move with your hand? You semed to reach for the left side (facing the car), where the air pump and AC compressor are located.

You need to probe around with a hose listening for where the sounds are loudest.

gosbollen

Garth: Do you mean the one that pumps air into the cats? That one I have.
But I have located the metallic ringing noise to the left "thingie" with the text "PORSCHE 32V" on it. Is this called air inlet? That sound is still there. Not as loud as it was at first startup though. This symptom also appeared after the service. Is it possible that a thicker oil may have disguised engine noise like that?

Bill: I filled the filter up to 3/4 before mounting. I did not have a microphone. The cameraman moved to the front of the car, and the sound may have been clearer there.


I will try to pinpoint the sound more accurately the next time I'm at the garage. I went there today and put some injector cleaner inte the tank. Didn't have the time to drive though.. Will hopefully take her out for a spin tomorrow and check the results.

But I wonder... If the injectors are the reason for the noise, can you feel the ticking on the plastic cover? Is it possible that the lifters somehow can be felt up there?

Garth S

The plastic cover for the fuel injector rail is held in place by two 5mm hex key bolts: If the foam insulation underneath has disintegrated (as John had earlier noted), the cover may amplify the injector noise. Easy to remove and check - and verify the bolts to be tight.
The air injection pump is a 'vane' type, and can make all sorts of noises when the vane pivot bearings wear.
Yes, the 32V logo is on the (air) intake manifold - the only moving part inside is the "flappy" valve: it pivots on the vertical shaft covered by the 2 cm plastic cap in the center of the intake.
Does the ringing noise change with increasing engine RPM? Is it near the center of the valve cover (ie., chain drive for the second camshaft)? Do not know what the noise is, and guessing is a poor substitute!

gosbollen

I have now compared my car to 2 other s4's.
They had the exact same sound as mine, and I was told it was nothing to worry about.

It was indeed the injectors.
I will try to get rid of the noise sometime soon. But as it didn't turn out to be dangerous it can wait. I have plenty of other gremlins and problems to take care of

Thank you for your help.

tuk_928

Hello Gosbollen,

Thank you for the video documentation of your cambelt service and for sharing your concerns with the group. I'm a couple of years away from needing to perform this service on my 89 s4 but am studying up in my shop manuals and watching videos like yours whenever possible. The whole cambelt "thing" is the ONLY aspect about this car that TRULY scares the bejeezus out of me IMHO performing the cambelt service on your own 928 earns anyone their wings as a DIY'er. Happy motoring and congratulations on performing your on work!

Best,
Tim

gosbollen

Hi Tim.

I'm glad to hear that you liked the video.
I don't think you should worry to much about the cambelt service. It's not that difficult with the help of Pirtles writeup, the workshop manuals, the correct tools and some common sense.
This is actually the first car I've worked with, and that should speak for itself

Bernie

I thought that this was worth mentioning.
When you do an oilchange, prefill the oilfilter before you put it on but also do this.
Remove the fuel pump relay so the car cannot start.
Run the starting motor and monitor your oil pressure gauge until it jumps up. Once it does, replace your fuelpump relay and fire away.
You will get NO nasty chatter on initial startup.

This chatter is what scares the crap out of the lads at the local oil shop and makes them tell you that they are not certified to change oil on a Porsche ---LOL


Cheers

gosbollen

I felt no joy what so ever when I started her up for the first time after the service.
I WILL remove the relay next time
I did prefill the oil filter however!