Hi all bit of a puzzler for you,at around 1500 revs I get a noise which can only be described as a muffled ooooooooohhhhh!!! sound.I know when put into print this looks silly but I am totally stumped.The car is a 1990 s2,I bought it about four years ago and it made this noise then.I thought that when I did the belts,idlers chain and water pump it would have gone ,still there.last December I put a clutch in it and changed the belts(1500miles but three years old).I also fitted new mounts.To my annoyance the noise was still there,I then removed the alternator belt and the power steering belt to see if they had anything to do with the noise,still there I am stumped.The noise is engine related as if you have it in neutral and slowly go through the 1500-1700rpm range you get the noise.Can anyone come up with a direction to go next,thanks in advance John.
weird noise
- Thread starter pegasus
- Start date
pauljmcnulty
Active member
Mine does exactly the same. Suggestion was clutch release bearing. I just live with it!
Like I explained just put new clutch ,release bearing and spigot bearing in but the noise is still there,it is not affected by engaging or releasing the clutch and it is still there if in gear staitionary with the clutch released so that eliminates the torque tube bearings,its a sod.
pauljmcnulty
Active member
Mine had a new clutch just before I bought it. Just sounds so like my noise that I thought it worth mentioning. If there's a better suggestion it might help me!
Did you have a Turbo owner in the car with you? If so the noise is most likely to be them as they are not used to such immediately smooth and tractable power and acceleration.
S2 driver foot down and go!!!!!!!!
Turbo driver foot down wait wait wait wait wait wait wait and finnally wait and then go and change gear................... wait wait wait wait wait etc etc..
S2 driver foot down and go!!!!!!!!
Turbo driver foot down wait wait wait wait wait wait wait and finnally wait and then go and change gear................... wait wait wait wait wait etc etc..
Hi Paul I wish the noise was clutch related,I changed my clutch due to the classic rubber damper failure,original clutch by the look of it,clutch and spigot bearing were both dry and should have been making some noise but were not.After fitting nice new sachs parts and checking the torque tube for obvious noise (all you can do is spin it and see if it rumbles and grumbles) I was annoyed to hear the same noise I had since first purchase.Normally a clutch bearing will make a noise when under load,ie the releasing of the clutch,and the noise will change when the clutch is engaged ie minimal load on the bearing.If you get the noise when driving and not staitionary that would suggest drive train problems.If you get the noise when stationary in neutral it could be the clutch torque tube or gearbox related.If you still get the noise with the car in gear with the clutch pedal depressed that would suggest a noise from the engine,everything from the spigot shaft aft is stationary so would not produce a noise.If you then remove the alternator and power steering belts thus eliminating any chance of noise from them and still have the noise you are in the same position as me. you then change the balance and timing belts,replace the water pump,you are only left with the crank,balance shafts and cams spinning around and then like me your stumped.You can try the eliminations I have tried but if you are left with the noise you will be like me asking for help,all the best John.
924nutter
PCGB Member
This sounds like a noise that we would have to hear before making any suggestions. I like your logical process of elimination and you have covered most of the obvious things. It might be a vacuum leak making the servo diaphragm hum. Like the fictional Sherlock Holmes said, "once you have elliminated the impossible, what ever remains is the truth, however improbable.
pauljmcnulty
Active member
Lol, that's how I feel!
For what it's worth, mine makes a kind of "whoooooooooo" noise from around 1500RPM, rising and falling with engine speed. It's the same in or out of gear, stationary or moving. Never from cold, and it does get louder when the car's in heavy traffic and everything is heating up.
All my belts, pump, rollers etc. were done last year and no difference.
The only other thing I have problems with is the power steering, but that's a different noise and varies with steering input, not engine speed.
My indie said it was the clutch bearing, despite it being new, but an idea for a simple, cheap fix from someone would be most welcome! [
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924nutter
PCGB Member
Your are partially correct here, but how it goes is;
Porsche have conveniently provided a stick in the middle of the tranmission tunnel for the purpose of changing the very gears that you mention. Turbo drivers who think ahead and anticipate, like all the best drivers, use this stick thing to be in the correct gear to suit the characteristics of their engine, and the situation ahead, then it is as you say foot down and wait, wait wait wait wait; for the S2 driver to catch up. In the 944 Turbo the 928 and especially the 996 turbo, when you want to think about overtaking, you just do it, because you have power to spare. In the S2 you really just dont. Have you been watching that JC video about the 944?
I like changing gear it is what you left arm is for. [
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Could be air but I have changed the coolant at least four times in my ownership and use a sykes pump to pressure bleed the system on the day and always again when everything has settled and cold so I don't think it is air and I dont think these cars would have a design that has cavitation problems,It may be a problem on the air/vacuum side but where?
Trevor68
New member
Hi John,
I'm going to break from my usual lurking cover and suggest the OPRV could be a suspect. I had a weird 'woooing' noise after changing the oil cooler seals which turned out to be the OPRV that wasn't seated exactly.
Another wooing noise on mine that isn't really noticeable when cold but quite evident when warm is the fuel pump.
I'm going to break from my usual lurking cover and suggest the OPRV could be a suspect. I had a weird 'woooing' noise after changing the oil cooler seals which turned out to be the OPRV that wasn't seated exactly.
Another wooing noise on mine that isn't really noticeable when cold but quite evident when warm is the fuel pump.
pauljmcnulty
Active member
Mine has had the coolant drained and replaced, no difference. No other issues with those systems.
It's very definitely engine-speed related, coming in a bit over 1000 RPM and rising and falling in tone with revs. Probably a bit behind the engine speed IIRC, rather than being instantly changing with revs. Think revving the engine slowly from 1000 to 2000, in neutral, and you get a rising pitch "whooooooo", a bit behind the change in engine speed.
Must record it......[8|]
It's very definitely engine-speed related, coming in a bit over 1000 RPM and rising and falling in tone with revs. Probably a bit behind the engine speed IIRC, rather than being instantly changing with revs. Think revving the engine slowly from 1000 to 2000, in neutral, and you get a rising pitch "whooooooo", a bit behind the change in engine speed.
Must record it......[8|]
924nutter
PCGB Member
If you guys think it could be the fuel pump, and the lag in sound suggests that it is not directly connected to the engine try getting as assistant to gently rev the engine whilst you listen from the off side rear wheel where the fuell pump is. That said in my experience noisy fuel pumps seem to make a sort of sizzling hum.
I would not think that the fuel pump is involved as the the noise is directly in sync with the revs and the pump delivery is almost constant ,more than the engine ever needs pressure on the rail being maintained by the fuel pressure valve as this fuel has to be at a constant pressure so the ecu can vary fuel delivery by pulsewidth .
pauljmcnulty
Active member
I'd lay money it wasn't from the back of the car, although I know sounds travel in weird ways. I'd have said it was in front of my left foot, hence not questioning the clutch diagnosis.
Whether it's relevant, it doesn't happen all the time, so again that tends to make me think it's relevant that it's heat related.
My S2 makes a 'mooooo-ing noise sometimes when coming down from higher revs, often on the over-run. Only when hot. I think it's the oil pressure release valve, and have never worried about it. Could it be that?
(It also 'Quacks' from the door seals at speed if you have closed the doors while it is wet. Doesn't do it if you close the doors while it's dry and it subsequently rains though.)
Oli.
(It also 'Quacks' from the door seals at speed if you have closed the doors while it is wet. Doesn't do it if you close the doors while it's dry and it subsequently rains though.)
Oli.
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