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Alan Ahern

E39 M5 timing chain tensioners

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I finally got my dream M5 and I am getting it serviced soon. I am getting the usual service items changed along with changing the gearbox and diff oil, is there any point in changing the timing chain tensioners at this stage, the milage is 160k mls.

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The main chain tensioner is worth doing if it's still original.

 

The 2 tensioners in between the cams is quite labour intensive to replace. These can be checked for wear and play when the valve covers are removed. if you're replacing these tensioners, considering the mileage, it's worth while doing the chains and guides as you're about half-way there since the upper timing covers have to be removed.

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Main tensioner is a very good idea if its never been done.

 

ANy other tensioners and guides are as said pretty labour intensive to remove and replace although it can be done at home with pretty much normal tools if yu have the time.

 

If you are that concerned with the health of guides etc you could drop the lower sump and see if anything has broken up and ended up in there but in all honesty replacing the tensioner as a matter of course if you aren't hearing any untoward nioses is likely the best option in terms of spending and return at this stage

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What goes on the tensioner?

I have finally started work on mine. Omg soo much needs doing. I am starting to think I'll leave the guides as I've remover the sump and there was nothing at all there.

I've replaced the tensioner and I can't see what could go on it?

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Its just a case of its ability to hold pressure over long periods of not running, i.e overnight. The first signs of a tensioner past its best is a rattle on startup, sometimes form overnight, sometimes when the car is warm and has sat for less of a period because the oil is warmer and thinner so drains out easier.

 

Some theorise that owners that tend to favout out a pro active change of tensioner usually fall into a camp that has no trouble with guides further down the line, going as far to say that an old tensioner exacerbates the chains ability to thrash about on the plastic tensioners and break up the guides.

 

I know my guides were pretty sound after 144K and my tensioner appeared to be the original one, but after changing the tensioner amongst other things my cold and hot starts are noticeably quieter, and for a little peace of mind for about £120 its unlikely its the most expensive thing you'll buy your m5

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Thanks for the info all. There is no rattling and the car has an extensive service history. I am doing this as preventative maintenance. I might let it go another 5K miles before I do anything.

 

Does anyone know where I can get the main tensioner and roughly the price?

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Bit of a thread revival. Mine has a slight rattle and I’m wondering whether to replace the main chain tensioner - is there a DIY anywhere for this job and would it be something a non-expert spannerer could manage (I.e. total amateur)??

Edited by timk

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It is a straight forward job to remove the old and replace.

It is located half way down on the right side of the block (front of engine)

You can remove the right side air intake for better access.

 

Two things, not to cross thread on install.  2. The tensioner comes supplied in a compressed state, be careful not to play around with it as it may extend, making it very much more difficult to install with inc risk cross threading. 

 

The engine will rattle on start up until the oil fills the tensioner and it extends and presses the guides.

I think part 21 comes with it.

 

Part 20 

http://www.realoem.com/bmw/enUS/showparts?id=DE92-EUR-02-2002-E39-BMW-M5&diagId=11_2660

 

 

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If it does spring open it isn't possible to just push it on with a socket and ratchet, there isn't space and the spring is quite strong. The risk of cross threading it is serious if trying to force it like that.

 

I found it is possible to rest a pry bar / long screwdriver against the chassis leg to apply enough force to the back of a deep socket on the cap of the tensioner to overcome the spring. Carefully move it forward into place with the lever while turning the cap with fingers to start the thread. Once you are 100% sure the thread has safely engaged keep pushing with the lever and use an open ended spanner to turn it a further few complete turns. That will ensure the thread in the aluminium timing chain cover is protected. After that use a torque wrench to finish the job.

 

I needed to order the crush washer separately from Cotswold when I did mine a year ago. The tensioner came with a shiny new cap though!

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