Hi, I have a 2011 Mini Cooper Countryman s 2wd and the belt does a slight chirp every time I start the car and nothing else. I have an aftermarket ac compressor on the car and belt has been replaced many times. The belts wear very fast and break more frequently. I have replace the water pump tensioner a few years ago for failure. Have looked online to only be told to replace the belt again which has been 3 times this year already. Using autozone brand belt. Have a gator belt in trunk in case it fails. Any help will be appreciated!

 

With an otherwise healthy accessory drive system a chirp or 3 on cold start with one car proved to be a bad idler roller bearing. This was the 2nd time one of these -- there were two -- went bad. The 1st time I would hear a dry bearing sound. Replaced both the 1st time and both the 2nd time. After the 2nd time no more problems.

Oh, another condition that could cause a chirp or two was a cold start after the car was exposed to dampness. Rain or even heavy fog. Admittedly the accessory drive was a bit exposed being the car was a Porsche 996 Turbo with the engine compartment exposed to the elements via a louvered engine lid. Well, not all the engine but certainly the accessory drive was partially exposed. I was careful when washing the car and no problems but the few times it was parked in the rain or overnight on a hotel parking lot near the ocean and got exposed to some heavy fog.

The chirp was the slipping belt grabbing. I observed the battery voltage gauge and it was low ~12V but as the engine idled and not very long the belt/pulleys dried out and the belt spun the accessories -- including the alternator -- as designed.

Belts wearing fast suggests to me a misaligned accessory drive system. Or a bad accessory drive. One time when I was diagnosing a noise -- this with another car -- I had the belt off to check for accessory drive bearing play. The water pump had some. Not much but compared to the other drives which essentially had no play the water pump was suspect #1. I also noticed the inner edge of the belt was sharp. The outer edge was dull. I fished the old belt out and both edges were dull and that was after it had been in service for 60K miles. The bit of bearing play at the water pump had the belt tracking wrong and wrong enough it was rubbing. Had I let it go the belt might have failed.

Bottom line is you need to check the accessory drive alignment. I used a precision straight edge to check all the drives were in alignment. You need to ensure the tensioner is good. Proper belt tension ensures no slippage -- that chirp you report could be due to a loose belt -- and any slippage can only shorten a belt's life.

Also, you need to make sure all accessory drives have nice tight wobble/wiggle free bearings. And the idler rollers do not manifest any signs of bearing issues. Roughness. Excessive play. Even signs of seal degradation. Don't forget the tensioner roller.

 

thank you. I will remove the belt and check everything. I bought a gates belt and will install after I double check everything

 

Sounds like you should replace the tensioner, the perpetual belt problem is just an indicator of another root cause. You all ready replaced the friction wheel between the belt and water pump?

 

maybe it lost its tension from being used so much to replace the belts sigh! Will check that also thanks

 

Tensioners are a wear item...

 

it does move a bit while running. Is that normal or definitively a bad sign

 

Can be a sign of wear and weakened spring. There will be some movement but it should not be much.

 

ok I have a lot to work on this weekend so trying to get some direction. Have to replace valve cover gasket and this tensioner. I have a gates belt so that should help

 

I just changed the belt on mine last weekend with a continental from Autozone. So far so good. Got about 105K miles...

 

I have probably put 6 continental belts in the past 2 years. Has to be tensioner or something off. Only thing aftermarket is the ax compressor and I hope the guys installed correctly.

 

If you're doing the work yourself then you're an expert at the belt remove/install by now :-). Check the AC pulley, Alternator pully, Crank Pully. Hopefully the friction wheel powering the water pump is OK and not causing belt issues. A good and correct tensioner is key to the belt condition.

 

I will have to recheck those things to make sure. I replaced the harmonic balancer, water pump tensioner and ac replaced at shop due to me not having an evacuation of Freon.

 

Usually when I have to replace a compressor the freon is all ready gone and leaked out so ne need to evacuate... Why did you have to replace the water pump tensioner? Was the friction wheel on the water pump OK still?

 

the ac compressor was not giving cold air anymore no matter what and still had Freon. Don’t understand how or why! The water pump tensioner was replaced the first time because my harmonic balancer bolts broke due to last person who owned only using 2. This caused it to warp the 2nd screw, come loose partially and slap/break it. The second time I replaced the water pump tensioner was due to it being faulty. Now I have it good but it snaps belts when giving it the beans sometimes! I replaced the harmonic balancer by buying the kit. Probably should of done chain but will do later