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Bottom pulley vibration

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Hi all

Was running the engine following a bit of work and noticed a small amount of vibration in the bottom pulley. It’s enough that the tensioner is moving slightly. The center bolt on the pulley looks to be true so must be in the pulley. Anyone else noticed this on their engine?

 

The drive belt looks new but the tensioner looks old and slightly out of alignment as there is about 0.5 mm of belt off the front of the pulley. I think that will be my first thing to replace.

Edited by RandomName

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Like you already suggested renew the whole tensioner assembly ASAP. The aluminium body on the tensioner wears out making the pulley go out of alignment with the belt. This will heat the belt when engine running and in worst case the belt splices and part of it can be sucked in crank case thru front crank seal.

 

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if by bottom pulley you mean the one on the one on the end of the crank thee change it ASAP!  If that main pulley falls apart, which they do, you could take out the radiator and/or other bits at the front of the engine.  It's got a bit of energy when its spinning at a few 1,000 rpm!  The pulley has a rubber anti-vibration part in teh middle that can fail launching the pulley whe it fails - you also loose the alternator, water pump, and PAS at the same time just to sh1t you up a bit more!

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Thanks @Machinehead was thinking it might be safer to replace it especially as when I was in the local bmw dealer ordering the seal parts they mentioned a vibration damper failing. I assumed they were talking about the tensioner but now looks like it was the crank pulley that they were talking about.

 

Anyone know if this can be gotten aftermarket or is it a dealer only part?

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I got one from my local motor factors for roughly 1/3 of the price BMW wanted.....

 

its a right pig of a job if it’s the single bolt that holds it in place :angry:

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Thanks @Yokozuna. I think there are 6 bolts holding it on. Been scouring the web all evening trying to find one for the n52 Petrol engine but only finding genuine bmw ones at round the £500 mark. Will be ringing the local motor factors in the morning as that’s a bit more than I’d like to spend on one.

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17 hours ago, Clavurion said:

It seems that there are no after market alternatives for N52 vibration damper. :(

Yeah, had that confirmed this morning by one of the local motor factors. Found a relatively local one from a breakers that I think I’ll try.

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2 hours ago, RandomName said:

Yeah, had that confirmed this morning by one of the local motor factors. Found a relatively local one from a breakers that I think I’ll try.

D’oh 

oh well! :( 

that surprises me TBH! Your engine is obviously not common enough for a third party to make parts for.... 

good luck with the breakers part anyway.

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1 hour ago, Yokozuna said:

D’oh 

oh well! :( 

that surprises me TBH! Your engine is obviously not common enough for a third party to make parts for.... 

good luck with the breakers part anyway.

Yeah I’m a bit surprised as well given the various models that had the n52 engine but looks like options are now limited.

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Still waiting on the eBay special crank pulley to arrive but was doing the oil filter housing gaskets today so took the opportunity to change out the tensioner as I had the part and don’t need the car for a few days so can leave it on stands till the other bits arrive.

Torquing the tensioner bolt is one of those heart in mouth moments as the bolt stretches, but thankfully all seems ok.

While the belts off I checked the deflection pulley and it’s due a change as well. Anyone ordered the gates or ina pulleys that are all over eBay and can comment on how good or otherwise they are?

i would like to meet the last person who serviced the car as aside from the mess of oil mentioned in my oil leak thread, they changed the aux drive belt without changing the tensioner and deflection pulleys that are both in bad condition.

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The used crank pulley/vibration damper that I ordered has just arrived. It has 2 small chips out of the lip on the engine side of the pulley (looks to be cast metal so easily chipped). The chips don’t extend into where the belt sits.

The v ribs that the belt sits on all look in good condition, as does the rubber and weight. So the question is whether to trust it with the chips in the inner lip?

looking at others on eBay and most seem to have bigger chips out of the same inner lip.

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As I insisted in getting a manual I’m stuck with either new from bmw or 2nd hand.

Been quoted just shy of £400 for the new one but thought one from a breakers was worth a punt at £45 having 2nd thoughts about that now it’s time to fit the part.

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15 minutes ago, RandomName said:

As I insisted in getting a manual I’m stuck with either new from bmw or 2nd hand.

Been quoted just shy of £400 for the new one but thought one from a breakers was worth a punt at £45 having 2nd thoughts about that now it’s time to fit the part.

It might be worth buying a second one off a breaker and stick it in the boot along with all the tools required to change it (just Incase) 

its still cheaper than one from BMW. 

I think I was quoted something along the lines of £357plus vat off bmw for mine, but luckily enough there was many different after market companies that made the one I needed. 

 

Or you could do what my father in law done when he couldn’t get the one off his truck, use rubber cement and glue it back together! It’s still holding strong after 4 years.... ;) 

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Decided not to risk the 2nd hand pulley and have ordered the new one from bmw. Thankfully the breakers I bought the pulley from have agreed to take it back, though it’s little comfort given the price of the new one.

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New crank pulley arrived yesterday and was fitted last night and now the over thinking begins.

The torque setting for the bolts holding the pulley on was listed as 22nm which to me seems a bit light. In saying that it seems to match the effort needed to undo them.

There was no sign of any loctite on the bolts but I’m starting to think I should have used some. As I said the over thinking has begun...

The good news is that replacing the tensioner, deflection and crank pulleys along with the belt seems to have sorted the vibration in the crank pulley :)

Out of all those bits the only one that probably didn’t need replacing was the belt but thought I may as well comple the set.

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