Hello everyone.
First post - hope you can help me out a little.
I have a late 2005 X3 2.0d - bought it about a month ago.
When I bought it the A/C belt had been thrown. On further inspection the compressor turned smoothly and appeared to be ok. The belt, which was still in the engine bay, was complete but had a split about 30% round along one of the grooves. I assumed this wear was the reason the belt had come off.
I replaced the belt and whilst the A/C wasn't the coldest I'd ever felt it was working and I figured it could probably just do with a recharge and planned to do that in the next week or so.
Anyway, drove the car today ( it's now about 100 / 150 miles since belt replacement ) and the a/c was blowing warm / ambient.
Checked in the engine bay and the new belt had been thrown off. Belt's in perfect condition and compressor still turns okay by hand.
The serpentine belt and pulleys look fine with no nasty wobbles, shakes or vibrations.
It's no real hassle for me to put the belt back on, but wanted to see if anyone else had experienced this or had any idea why the belt has been thrown.
By the way...
The car has just 81,000 miles on it.
The belt is the type without the tensioner pulley and must be fitted with the stretch belt tool.
Thanks in advance.
Either the bearings or race is out of line, so i would inspect that tensioner/belt guide.
Using Tapatalk
How about AC compressor bushings? Not sure if you have them or not but surprised no tensioner.
Michael
I tried again and it seems to stay on when driving smoothly with lower revs / gentle acceleration. However, more aggressive driving with higher revs throws the belt. I think the compressor's okay, but starting to think it might be the crankshaft pulley / damper.
Re. Tensioner - yes this model doesn't have one. Instead it uses a 'stretch belt'. Fitting is a little more difficult but is made easier with a stetch belt fitting tool.
Here's a clip to illustrate: https://youtu.be/5mrB5mH3qBo
Althbough I have not seen this on an e83, there was an issue with e9x that would throw or destroy belts due to a failed motor mount, specifically the bolts holdoing the aluminum arm to the block were failing. Also I would check the alignment of the pulleys across both edges of both pulleys with a straight edge. Also if there is any wobble at low RPMs that would be magnified at higher RPMs, the math for the distance the belt is travelling at 2000 rpm's vs. 4000 rpm's should be pretty straight forward, but I'm feeling a little lazy this AM.
Thanks guys.
Changed the Crankshaft pulley and we're all good now. Thr rubber damper was worn.
Belt nice and straight... a/c working... belt stays on!
I have exactly the same problem in my X3 2.0 TD (E83)
I wonder how hard you found to replace the crankshaft pulley.
which brand you used replacement?
......
update.
I confirm, I also had a bad crank pulley / harmonic damper. It was an original BMW part. Failed after 130,000 miles.
Taking it apart does require to loosen the 22mm nut. This is doable - rather physical - you must have the right tools and be 100% methodical. Most importantly when fitting the new one, you must apply the correct mounting torque: 100Nm with torque wrench, and then tighten + 60deg and again +60deg, altogether 120deg with a 3/4inch breaker bar minimum extended to 1m or better 1.5m. Throughout the operation, the pulley must be held with the special BMW spanner - any other way entails high risk that you will damage the engine and/or injure yourself.
Last edited by MichaelF; 07-19-2020 at 01:10 AM. Reason: Update
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