Whirring Sound - not good
 

my early 85 is making an intermittent whirring sound. particularly noticable at idle.Ussually noticable after warmup. If I bring the rpm up a little bit then let it settle to idle it sometimes stops.If you have ever heard a sprint car supercharger - that's what it sounds like... kind of a rring..rring. rring sound. HELP Water pump? Belt?

RE: Whirring Sound - not good
 

It could be Irritable Bowel Syndrome. How often do you move your bowels? I'm good friends with a gastroenterologist, and he's having a Christmas sigmoid endoscopy special.

RE: Whirring Sound - not good
 

sounds to me like SARS

RE: Whirring Sound - not good
 

whirring c'est parfaitement naturelle!

RE: Whirring Sound - not good
 

Could it possibly be the cooling fans? If you have the older style 3-blade fans, they're particularly loud / noticeable. This is normal.

RE: Whirring Sound - not good
 

Cooling fans sounds like a good tip. Check if the sound starts when your engine temp is high.

RE: Whirring Sound - not good
 

I'd be looking at the balance shaft idler pully as well. Your description sounds exactly like a mis adjusted pulley. Don't worry, its an easy and cheap fix if thats it.

Regards,

RE: Whirring Sound - not good
 

That sound may also be from the balance shaft belts that are tensioned too tightly. Manual recommends 2.7 for the balance shaft belt, which is quite loose in reality. SOme mechanics like putting it on ~3.5+ for safety..........

RE: Whirring Sound - not good
 

Mine's always made a whine, but it seemd constant at idle, would go away at higher RPM.

I would check the tension, and if that's good, than not really worrya bout it. If you haven't changed your belts, rollers, or waterpump in a while, I would suggest it. It could be waterpump on its way out.

RE: Whirring Sound - not good
 

If a so-called "mechanic" is tensioning the balance shafts to 3.5, I'd rap them upside the skull with a crescent wrench. Tensioning the belt tighter than factory spec will NOT help and can in fact break things with catastrophic results. As the engine heats up, things expand and the already too-tight belt can run the risk of snapping. If it does, you can almost bet that shards of it will mess with the cam belt and if THAT happens, you just bought eight (or sixteen) new valves, possible head machining, possible piston replacement, possible BLOCK resurfacing / boring or replacement due to busted valve fragments scoring cylinder walls, etc, etc, etc. DO NOT OVER TENSION YOUR BELTS!!!

Let me say that again:

DO NOT OVER TENSION YOUR BELTS!!!

Is that clear enough?

Tell that "mechanic" he / she is an idiot and take your business elsewhere. Or better yet, do it yourself.

RE: Whirring Sound - not good
 

If you noticed, MANY mechanices (porsche trained and dealers themselves) install new belts at 4.0 for both timing and balance shaft. Only the 944 mechanics (or the ones who know their way around them) know the little bits and pieces that the manual specifies.


Worse case scenario of over tightening balance shaft belts? amazingly rought idle with a jet-engine sound comming from the engine, along with a smoking exhaust, balance shaft bridges chatter (yes they get noisy) and the whole car shakes like an LA earthquake hitting 10+ on the scale (if it ever did :p) That was the case done on my 88 NA (RIP) and turned out that the factory tool was out of calibration and the belts were on a 5.6 if i recall. Which is extremely over the limit.

BUt even now when i tell then, call them and fax them regarding tensioning the belts, they seem ok with the timming, but still have a ~3.0 on the balance shaft belt (which is acceptable since the manual specifies 2.7 +- 0/3 i believe).

RE: Whirring Sound - not good
 

Check the tension on the belts. Sounds like they may be too tight. The manual says to set them to 2.7. This is a setting for a new belt. As the belt is worn, it will stretch a bit. Keep in mind that the tension must be checked at 1500 miles, and then again at 15K. If they sound too tight, back them off a bit. When tight, the balance shaft belt will feel LOOSE. You can easily turn it 270 degrees from the middle of the run from lower to upper shaft.