Strange engine noise? Help please!

scottmandue · 05-28-2002, 12:01 PM

Okay maybe I'm just being paranoid and it is hard to describe the noise but here goes. I have had the car for about two years now and it runs great and the belts were done only 6K miles ago and retensioned around 800 miles after that. The car has made this sound since I first bought it but it runs smooth and strong so I have not been too worried about it. BUT I want to know if this is normal or not because I am thinking of taking the car on a five hundred mile vacation next week.

This is the best I can describe it: At idle with the hood open I hear a oscillating whirring noise from the front of the engine. I did the old tube to the ear trick and it seems to be right under the belt cover near the distributor. The sound is not obvious when driving at speed and the engine idles smooth.

I have been hoping to find another 944 owner nearby so I can listen to their engine to see if this is normal but I have not been able to hook up with anyone yet.

Any ideas?

Gordon Rankin · 05-28-2002, 12:30 PM

Scott, It looks like I will be getting my 83 on June 1st. Email me and I will try to get over since I will be in the area.
Gordon

Cebu · 05-28-2002, 12:51 PM

Check closer for the sound at the power steering pump

Bob's944 · Bob's944's Garage

When was the waterpump replaced last? It's under the cambelt cover. Other possibilities are one of the belt rollers going bad.

scottmandue · 05-28-2002, 02:41 PM

Water pump was changed with the belts about 6K miles ago. Power steering pump changed not too long ago. Changed oil about a month back, inspected PS system at that time and it looked okay.

Belt rollers are my biggest fear

Thanks guys, keep the ideas coming.

GO LAKERS!

seb928s · 05-28-2002, 05:29 PM

Could it be that the timing belt is too tight? It would make a noise like that.

Lawrence Coppari · 05-29-2002, 03:25 AM

A tight balance shaft belt makes noise too - a whirring sound.

97XRAY · 97XRAY's Garage

Scott,
Why in the world are you afraid of the belt rollers? Obviously you need to just sit down and give your soul over to the porsche gods... ALL OF IT. Don't try to save any last part of your soul, you must give it all.
Then your fears will become happy stories of mechanical triumph, and of course, cost and aggravation will be completely UN-important to you; your soul will be fulfilled!
--Fellow belt roller replacement man

scottmandue · 05-29-2002, 06:59 AM

I tend to agree that the belt is too tight because as the car warms up it seems to become less noticeable. The car runs fine so I have put off taking it to a mechanic for almost two years now (I only drive the Porsche on weekends).

Most important,
How bad is it to drive the car around with the belt too tight?

Am I courting disaster?
Should I stop driving it?
Should I not take it on vacation?

I am not ready to attack the belt tightening job myself, I start vacation this Sunday and I work this Saturday so I can't do anything with the car before I go.

What do you guys think?

Lawrence Coppari · 05-29-2002, 11:54 AM

My balance shaft belt makes noise - the whirring sound. Usually it goes away after the car get a couple of hundred miles on it. Mine has about a 1000 miles and one track event but still is making the noise. Before the next event, I'll loosen it a wee bit. Mine has always done that. Before I began working on these things I had the local dealer do the belts. When I got the car back, it was whirring. It eventually quit whirring. I assumed since they did it, it was ok. They are competent. I'll loosen it a skosh nevertheless. I put this one on myself.

I suppose the belt could snap. If that happens, it could get into the timing belt. That would be bad. But I doubt it'll snap because it is not very tight at all. In fact, mine has to almost be floppy to shut up.

A year or so ago on this list someone mentioned the type of belt has something to do with the noise. I don't recall who the poster was but he was a regular and knows what he is talking about.

I'm not overly concerned about it.

scottmandue · 05-29-2002, 12:14 PM

Thanks Lawrence,

It sounds like that is where I am at and I suppose that it is better to have the belt a little too tight that a little too loose. I presume I am just being worrisome because I'm going on vacation and this is the first trip for the Porsche. But the weather looks good so it looks like I will give her a bath, check the fluids, and head for the highway.

Thanks guys,
Scott

ae1969 · 05-29-2002, 02:16 PM

Too really make you think..................

My guess is that the belts may be too loose...... as the engine warms up the belt actually tightens...... from 4 on the p9201 gauge to close to 9! as the engine warms up.

My belt was loose at around 2 on the gauge. I found that it was flapping and hitting the plastic housing (evident by the marks on it).... as the engine warmed up, the engine would expland and the belt would tighten....

Lawrence Coppari · 03:32 PM

Belts don't get shorter as they age. Why then does the noise generally go away with use? It's a constant whirring sound, not intermittent as a belt slap would be. At least on mine it is.

I'll get the stethoscope to it again before I go the next event. It is not the water pump or cam bearing because I already checked them out when I first heard it. Those would be serious.