Timing Chain Tensioner

[JMI]

Is this something that should be changed as a matter of course? If so, when? Anything else from that section as long as it is already opened up?

TIA

[JMI]

Bump

[JMI]

So is replacing the timing chain tensioner considered a scheduled maintenance item.
If so at what mileage?

TIA

[JMI]

Anyone?

[John in CT]

well, on my Saab 900 the tensioner has a max "extension" after which you live with it or replace the chain, which is a big PIA. Don't know about 535 engine,

Sorry,

John
1995 525i 5 speed

[632 Regal]

nobody is on over long weekends...

[yaofeng]

I was going to open my big mouth and then I saw the car is 89. Having opened the engine up on my 95 525i, I know the tensioner is different from my SAAB's. The SAAB tensioner has a toothed rod pushed by a spring from behind inside the tensioner. So th rod goes only one way to keep the chain tout as the chain (supposedly) stretches.

The BWM tensioner is different. There is only a spring inside to keep the chain under some force. Further, after 1995 the tensioner design was changed. There is no more small cover nut on the tensioner.

http://i21.photobucket.com/albums/b274/yaofengchen/BMW_95_525i/DSC_1743-1.jpg
New tensioner has a different design than the old one.

But I can't answer your question whether to replace it or not. I don't even know if the 89 is the same as the 95. I'd inspect it. If it looks good, put it back.

[mamilapon]

This is my personal opinion:If BMW thought it was a maintenance item they would have said so. The only thing that i reckon can interfere withthe proper operation of the tensioner is real dirty oil causing sticking piston and hence sloppy chain hence excessive link friction and eventually chain failure. So regular oil and filter change,checking of oil spray bar bolts, and sensible driving = lifetime chain.

[genphreak]

Got into mine when doing the cylinder head and timing gear. It is a simple arrangement but the fan, radiator (requires a special 32mm/3mm thin spanner) and so on all need to come out so you can strip down the timing cover. The biggest PITA is the crank nut, it is almost impossible to break free as Deiter had definately had a bad week when he was bolting all the balancers to M30 crankshafts. He put over 300lbs on them and since they all seem to become even more frozen as time has gone by. You WILL need penetrant, a 3/4" drive 36mm socket and a strong 3/4" breaker bar with at least 4' of water pipe to prevent it from saying no. Also, you have to lock the engine- if your car is a manual you can put it in gear but this risks a bent crankshaft. You really have to lock the crank at the front using BMW special tool part #11 2 220... other ways do risk bending the crank shaft.

The timing chain is a wear item... best to go at 160,000 miles (from what little I know). When doing the chain, you must also do the cogs (sprockets), but it runs off the main crank sprocket which also drives the the oil pump chain- this will also need repalcement and necessitates lifting the motor a few inches and pulling the pan. It is around this mileage one would also want to do the oil pump and they are cheap anyway.

You must replace the timing chain guide rail. With the tensioner, I think the spring is fine to stay- but the check ball on mine has disappeared... not sure what you will find on yours. Be careful removing jic you miss it. I'm still waiting to find out if it needs to be a metal or a plastic replacement, I've never seen the damn thing so I don't even know what diameter to use..

Oh and last thing, with the timing cover, make sure the bolts all go back into the holes from which they came, there are lots of them and you will not be able to work out much other than Deiter's friend upstairs drank too many Steins the night before he specced the timing cover fasteners on Falkenhausen's great new mill... :) Nick

Either that or he was pissed w Dieter for not keeping up with the pace or paying for his fair share of Steins...

[yaofeng]

This is my personal opinion:If BMW thought it was a maintenance item they would have said so. The only thing that i reckon can interfere withthe proper operation of the tensioner is real dirty oil causing sticking piston and hence sloppy chain hence excessive link friction and eventually chain failure. So regular oil and filter change,checking of oil spray bar bolts, and sensible driving = lifetime chain.

I agree. The tensioner is not a maintenance item.

I changed mine only bacause I cut the aluminum chain guide during dissembly. The guide is also not a maintenance item either. I replaced the guide with the new design of plastic guide. Along with it the new style tensioner must be installed. You will notice the old besign the piston end is recessed. The new design the end is smooth.

http://i21.photobucket.com/albums/b274/yaofengchen/Re-exposureofDSC_1705.jpg

[genphreak]

How can it not be? It pushes on the chain, has to wear as a result. Mine was pretty scored/worn at 230,000km. But I agree, you'd think BMW would say so, however I bet they don't say it for the oil pump either- it's simply whether you'd like insurance from wear related failiures- perhaps BMW feel it should last for ages and beyond that failiures, even catastrophic ones, can be paid for when they happen... :) Nick

ie 'Wat? Buy ze new Auto!'

[BillionPa]

its not a maintainence item... untill the motor warranty has expired!

if something IS supposed to replaced at a specific interval, and that interval is longer than the motor warranty, it will be a "lifetime" item (like the 540 tranny fluid). what that means is that when your car breaks, your cars life has ended.

they want you to buy a new car, having a car with engines that go half a million miles isnt good for business.

[632 Regal]

cant sum this up better.
having a car with engines that go half a million miles isnt good for business.

[genphreak]

its not a maintainence item... untill the motor warranty has expired!

if something IS supposed to replaced at a specific interval, and that interval is longer than the motor warranty, it will be a "lifetime" item (like the 540 tranny fluid). what that means is that when your car breaks, your cars life has ended.

they want you to buy a new car, having a car with engines that go half a million miles isnt good for business.ROFL... hahhhaa Thanks BillionPa!

Well I'm putting 160,000 milers on that one.

Maybe we in the enthusiast community should release a new version of the service schedule- for older cars: To look after them beyond the warranty period!

[Dash01]

For those who have removed the 36mm nut at the front of the crankshaft:

Did the threads have factory Locktite on them?

When you re-installed the 36mm nut, did you use Locktite?

Would heating the nut with a propane torch help with loosening it?

[mamilapon]

You got a point!