gnat

This morning it was in the mid-40s and until the temp gauge started rising there was a squeal from the engine when idling. The noise would go away as soon as the RPMs got around 2k and once the engine started to warm up it went away for rest rest of my commute and all seemed fine otherwise.

Am I correct in suspecting the belts are just getting old and slipping a bit or is there something else more critical it is trying to tell me?

ivangene

spit on it


or change the idler pulley's - the bearing go out - easy DIY repair (there are 3)

DBJoe996

There is no reason for the serpentine belt to squeal unless there is a problem. When was the last time you changed out the belt? If it was damp it could be condensation formed on the belt overnight if it was parked outside. Old dried out belt might do that if there is any moisture on it. A new belt would probably stop that. They are very inexpensive and worth the peace of mind. The rest is pretty straight forward...remove the belt (might as well put a new one on), check water pump, alternator, idlers, power steering pump, etc., for free movement, no binding or sloppiness in turning them over.

gnat

Thanks guys, is there a good DIY guide for this or manual (Bentley, etc) that covers it?

gnat

Unless they replaced it during one of the RMS repairs, it looks like its the original (2001) belt and we're at 65k right now.

Worst case and the belt snaps, what would we be looking at? Not that we'll put it off long but the BMW engines really crap themselves when the timing belt goes.

Hurdigurdiman

theres a great youtube vid here...
Before you actually take off the belt. Take a photo of it with your phone then you will have no trouble putting the new belt over the correct pullies in the correct way. BTW its a real easy DIY and the first one that I did on my 1999 996. Have fun.

Barn996

If it isn't the serp belt it may be the SAI you heard.

DBJoe996

It is a drive belt not a timing belt! But if it breaks you are dead in the water anyway. If you run the engine without it you will experience engine failure due to lack of coolant circulating. You should just jump in and replace the belt and check the other pulleys. You will be amazed at how simple a job this is (see the video).

gnat

Not going to put it off, just needed to know the risks of driving it much more. Not cooling properly is survivable as long as you pay attention to your cluster. In the BMWs the TB drives the water pump/alternator/power steering as well, but since its an interference engine you get all kinds on bent and broken internals when it goes.

Thanks for the info everyone. I'll look at the link tonight when I get home.

sjfehr

A failing air-oil-separator can sound uncannily like a slipping belt in some cases, too.

gnat

Thanks for the video link. That indeed looks simple enough to do in front of the house (no garage).

Macster

Uh, no. You can look at the instrument cluster until the cows come home, but if the belt snaps the water pump stops pumping coolant. There is no coolant flowing past the sensor so the coolant temp looks ok until it is not.

If you have not already done so replace the serpentine belt. If it is not due on miles it is due on time. Tires are due to be replaced after 6 years. I would think a serpentine belt would be due after that much time as well.

Check the old belt for sharp edges -- a sign it is rubbing and thus tracking wrong due to an accessory drive that has excessive bearing/shaft play.

Check all accessory drives for any play.

Check the idler roller bearings and tensioner roller bearing for any excessive play, roughness, drag or signs the seals (inside and outside) are going.

Sincerely,

Macster.