mauquier

Greetings experts. I've searched the forums but I haven't found any posts close to my issue. Maybe you can help. I have a '83 944 NA. In the middle of a normal drive I began to notice a whirring type noise that would rise in pitch as the revs rise. At highway speed, the pitch is so high the noise is not noticeable, but it is very distinct at lower speeds and at idle. This noise is loud enough to be heard inside the car and in fact, sounds sort of like a siren (had me looking around for emergency vehicles for a while). I'm thinking water pump on its way out, maybe? Alternator? Some impending belt doom? Please share your thoughts.

Thanks.

Brett Jenkins

I had that same noise when I first bought my 85. It went away when I changed the oil and filter the 1st time. Weird.

Peckster

How old are your belts? When was the last time you checked them?

Charlie

Do a search on "belts and whirring".

Chris_924s

I had a similar noise appear out of nowhere- about 1/2 way into a 50 mile trip I noticed an increasingly louder whine , loud enough to pull over to investigate. The sound seemed to be coming from the alternator, And Thanks to Luis, I determined it to be the alternator bearings beginning to go.

This wasnt directly related to RPM, but it was louder at a higher RPM. I let it cool down and the noise hasnt returned since. (I know the alternator will be replaced shortly, so my car has been on extremely light duty - but still daily driven)

HTH.

Welcome to Rennlist!

mauquier

Thanks for the comments, and the welcome.

I had the belts changed when I had the water pump replaced about 4 years ago. This is not a daily driver and I might put 1K miles per year on the car. I would like to think the water pump and belts are okay. I've never had the belts retensioned as the shop that did the work never advised it (and I'm just now learning the importance of this thanks to this forum).

I was encouraged by the post about the alternator. That sounded similar, but this noise doesn't go away when cooled down.

So I should focus on the belts, then?

Chris_924s

See if you can locate the source of the noise- a squeal or more of a whine? A squeal is normally a belt issue- make sure all the belts are tensioned properly. Timing and Balance belts are critical- accessory belts less critical. You can twist the accessory belts for a quick tension check- 1/2 to 1/4 turn on the PS belt. 1/8 to 1/4 turn on the Alt/ AC belt. The AC belt should be tight, and very little deflection when pressed with a thumb.

My alternator had a high pitched whine, as I said not necessarily RPM related. It did get louder at lower rpm's in city traffic than highway speeds, but it seemed to get louder the warmer the ambient temperature and engine got.


Luis may see this and add more..

mauquier

The noise is definitely a whine not a squeal. In fact, it sounds like a loud supercharger. The closest I can get to locating the source is the front portion of the engine. I'll try to pick up one of those mechanic's stethoscopes and check again.

Chris_924s

I'd bet money it's the alternator.

You can use a long screwdriver as a stethescope. Place the blade end on the case of the alternator and listen through the handle.

CAUTION!!! There is LIVE voltage present- if you are the least bit hesitant DONT do this.

Luis de Prat

If it doesn't go away, it sounds like the alternator indeed. Only similar sound would be the waterpump, but you did replace it. What are the miles on this car?

Open the hood and determine which side of the engine it's coming from. Alternator bearings going bad will get progressively worse, until they seize and kill the unit.

You can get it rebuilt or buy a rebuilt unit to swap it out.

Chris_924s

Luis.. Thanks.

Luis de Prat

You're welcome! I don't profess to be an expert by any means, but for the past 10 years I have been trying my best to keep a 1983 944 running!

Chris_924s

I've only got 7 years of daily driving in mine and I'm STILL learning things.

It's nice to have a few "long term" guys around. LOL

Edited~

Luis, I owe you a virtal drink and then some. How about a Tanqueray Sapphire Martini, double olive and a Macanudo!!

Luis de Prat

Mmn, sounds good. I'll take you up on the offer. Maybe we can meet up sometime. You guys in the Ohio area seem to have the "944 group activity/GTG" concept down pretty good!

I hope this works for our friend, mauquier, here. Good luck with the car, man!

hosrom_951

Sounds like the balance shaft belt is 'too tight'

My specialist LOVES to make things tight, just not too tight.

It would sound like a wirrrrrr....going on, as you rev up, the pitch gets higher...........are the belts new? did you just come back from a T-Belt/Balance Belt retentioning/replacement job?