Auxiliary Drive Belt and Tensioner + Preventive Maintenance
Discussion
I recently had my MOT on my 66 plate M2 which has now done 35000 miles. They mentioned that the drive belt had a bit of play. He said it would likely be okay but wanted to point it out. Anyway the quote to replace was £277. What do you think of the price? Also how often are you supposed to replace these? What do you consider good practice?
It also got me thinking as the car is 8 years old now if there were any other preventative maintenance items that’s should be done. I have heard about plastic charge pipes etc. Does anyone have a list of what should be done and when. I had the diff oil done at the time of the last service.
My car has been absolutely faultless with no issues at all since I picked it up 7 years ago but I plan on keeping the car a very long time so want to make sure it’s well looked after. Cheers.
Edit - I am also interested in the same for the S55 cars as well as N55 as I have an M3 also.
It also got me thinking as the car is 8 years old now if there were any other preventative maintenance items that’s should be done. I have heard about plastic charge pipes etc. Does anyone have a list of what should be done and when. I had the diff oil done at the time of the last service.
My car has been absolutely faultless with no issues at all since I picked it up 7 years ago but I plan on keeping the car a very long time so want to make sure it’s well looked after. Cheers.
Edit - I am also interested in the same for the S55 cars as well as N55 as I have an M3 also.
Not sure what the drive belt refers too. I'd hazard a guess the accessory drive belt? Serpentine? Or V-belt? And some cars -- my 2002 VW Golf TDi being one -- came with a rubber timing belt which drove the cam and the water pump.
(I owned 2 230 models (230, 230ix) and a 2023 M2 and I never looked at the drive belts. Cams were chain driven, I think...)
With other cars fitted with either a V-belt or a serpentine belt (and even one car fitted with both types plus the cam timing belt) the manufacturer had a replacement schedule. The one I remember (still) is my 2002 Boxster. The serpentine belt was to be replaced every 60K miles. Oh, and the rubber timing belt on the VW Golf replacement schedule of the timing belt was 80K miles.
Not sure what a bit of play refers to. Belts are under considerable tension -- thanks to the tensioner. One test was if one can depress the belt at the center of its longest stretch between pulleys/idler rollers beyond a certain amount that suggests the tensioner is weak. Belts can be checked for signs of aging/degradation. Serpentine belts can have cracks across the v-ribs but no sections of any v-rib missing.
The only play I have encountered in any accessory drive system was with the Boxster's serpentine belt removed the water pump pulley had a bit of play Not much but checking the other accessory drives: power steering, AC compressor; it was clear the water pump had play. Any play ain't good. I had the car in and the water pump (and T-stat) replaced (this at 172K miles). Oh, I was prompted to check for accessory drive issues due to a low volume deep rumble/grumble sound. With the belt removed and the engine started the noise was absent. So I knew it was coming from the accessory drive.
My advice is to look into the replacement schedule of the various belts replace those that are due -- or past due. At the same time the tech will (or should) check the accessory drives for any signs of play. He should also check the idler rollers and tensioner roller for any signs of bearing problems (looseness).
I have had excellent luck with accessory drives. When I bought my 2002 Boxster and I became aware of the very long serpentine belt and the 2 idler rollers and tensioner I bought a spare kit of these. Put them in the trunk. When I sold the car 16 years later with 317K miles the kit was still in the trunk. All I had to do over the years was replace the belt on schedule and replace the water pump.
But I have had terrible luck, too. My VW Golf TDi lost a belt -- V-belt -- on the freeway. Thankfully the timing belt turned the water pump so I could keep going. I drove straight to a VW dealer and as soon as I could -- his happened the day before Christmas -- booked the car in and got this fixed. Oh, the belt was not due to be replaced the alternator developed a problem which caused the belt to fail. The service department had to replace not only the belt but the alternator. At around 70K miles I had the timing belt replaced. 10K miles before the called for replacement at 80K miles.
And my 2003 Porsche 996 Turbo. On a road trip heard a dry bearing noise. Rather than continue to drive east and cross a large stretch of desert in the southwest US I turned around and headed to my local dealer. Tech found a bad idler roller bearing. This was replaced under warranty. But as a precaution I had the tech replace the others and the tensioner. Some years and thousands of miles later heard a faint chirp. Another bad idler roller bearing. This time the car was out of warranty. I had all the idler roller bearings and tensioner replaced. I don't recall at what miles but I drove the car to 161K and the accessory drive was fine.
(I owned 2 230 models (230, 230ix) and a 2023 M2 and I never looked at the drive belts. Cams were chain driven, I think...)
With other cars fitted with either a V-belt or a serpentine belt (and even one car fitted with both types plus the cam timing belt) the manufacturer had a replacement schedule. The one I remember (still) is my 2002 Boxster. The serpentine belt was to be replaced every 60K miles. Oh, and the rubber timing belt on the VW Golf replacement schedule of the timing belt was 80K miles.
Not sure what a bit of play refers to. Belts are under considerable tension -- thanks to the tensioner. One test was if one can depress the belt at the center of its longest stretch between pulleys/idler rollers beyond a certain amount that suggests the tensioner is weak. Belts can be checked for signs of aging/degradation. Serpentine belts can have cracks across the v-ribs but no sections of any v-rib missing.
The only play I have encountered in any accessory drive system was with the Boxster's serpentine belt removed the water pump pulley had a bit of play Not much but checking the other accessory drives: power steering, AC compressor; it was clear the water pump had play. Any play ain't good. I had the car in and the water pump (and T-stat) replaced (this at 172K miles). Oh, I was prompted to check for accessory drive issues due to a low volume deep rumble/grumble sound. With the belt removed and the engine started the noise was absent. So I knew it was coming from the accessory drive.
My advice is to look into the replacement schedule of the various belts replace those that are due -- or past due. At the same time the tech will (or should) check the accessory drives for any signs of play. He should also check the idler rollers and tensioner roller for any signs of bearing problems (looseness).
I have had excellent luck with accessory drives. When I bought my 2002 Boxster and I became aware of the very long serpentine belt and the 2 idler rollers and tensioner I bought a spare kit of these. Put them in the trunk. When I sold the car 16 years later with 317K miles the kit was still in the trunk. All I had to do over the years was replace the belt on schedule and replace the water pump.
But I have had terrible luck, too. My VW Golf TDi lost a belt -- V-belt -- on the freeway. Thankfully the timing belt turned the water pump so I could keep going. I drove straight to a VW dealer and as soon as I could -- his happened the day before Christmas -- booked the car in and got this fixed. Oh, the belt was not due to be replaced the alternator developed a problem which caused the belt to fail. The service department had to replace not only the belt but the alternator. At around 70K miles I had the timing belt replaced. 10K miles before the called for replacement at 80K miles.
And my 2003 Porsche 996 Turbo. On a road trip heard a dry bearing noise. Rather than continue to drive east and cross a large stretch of desert in the southwest US I turned around and headed to my local dealer. Tech found a bad idler roller bearing. This was replaced under warranty. But as a precaution I had the tech replace the others and the tensioner. Some years and thousands of miles later heard a faint chirp. Another bad idler roller bearing. This time the car was out of warranty. I had all the idler roller bearings and tensioner replaced. I don't recall at what miles but I drove the car to 161K and the accessory drive was fine.
kef9 said:
Thanks for the post. That’s a lot of history 
Sorry I was referring to the auxiliary drive belt and tensioner. I haven’t done anything about it yet. I was wondering if anyone else had done theirs and what the cost was?
Lots of history. Comes from driving ~1M miles. And of course not every mile was trouble free.Sorry I was referring to the auxiliary drive belt and tensioner. I haven’t done anything about it yet. I was wondering if anyone else had done theirs and what the cost was?
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