W124 Belt + tensioner

[eddie_E]

Hello all, i'm new to the world of mercedes and very pleased with my E200 It has a few small things that need to be done to get it spot on, one of which is there is a light ticking from the engine. I've done a search and found out its most likely the sepentine belt/poly belt/ribbed belt (what is it correct name?) and tensioner. One post mentioned the tensioner bearing is a Mercedes only part! is this because it not worth messing about with a pattern part or is it just the bearings on their own and the tensionr can be fixed. Does anyone know how much mercedes charge for a belt and tensioner? they're £9.50 and £17.95 respectively from GSF.

The other thing that needs doing is some of the dash illumination bulbs have gone. Most are 12v 1.2w bulbs but the ones that light up the little arrow on the fan and direction knobs have a grey plastic base. I changed these for the all glass 286 but the knobs are getting hot and appear a bit bright at night. Mercedes would only sell me the 286 bulbs but I must need a lower power bulb for the knobs?.

 

[jeffreyli86]

Are you sure it's not the tappets?

 

[Vlad]

From experience you normally know when the tensioner is on its way out when you start getting a sort of continuous rubbing noise....the ticking does sound like a sticky hydraulic tappet. Does it sound like an old typewriter?

Also does the noise go away when you rev the engine past 1500?.....if it does, I reckon you have a noisy tappet which is nothing to worry about. Quite a common Merc engine trait!

Re the costs of a complete tensioner/lever assembly, mine cost £41.50 +vat and my belt cost £23.34 + vat.....thats for a 300d, so I would imagine the parts for a 200 would be slightly less from an MB dealer.

Cheers

 

[eddie_E]

Are you sure it's not the tappets?

I'm not sure wgat it is, but it appears to be coming from the water pump but I think its just the vibration from the tensioner being transfered along the belt.

Also does the noise go away when you rev the engine past 1500?.....if it does, I reckon you have a noisy tappet which is nothing to worry about. Quite a common Merc engine trait!

I have read this in other posts but i would say it doesn't. It gets almost unnoticable when it's warm at tickover, if i floor the throttle upto high revs it sounds a bit tappy. I think my list of possibilites are the belt and tensioner, the water pump or the timing chain, maybe. It isnt really very loud at all it just the rest of the car is so smooooooth i jsut feel it's letting it down a bit and if i coud cure it it'd be floorless

 

[Vlad]

If its of any use in diagnosing the problem, on my car the belt got noisier as the car got hotter.

I again come back to the tappet....from cold if you have a duff tappet it will be a loud ticking as the tappet will have bled down whilst the car has been standing. Once the engine is nice and hot and the oil is thinner, the tappet will eventually pump itself up.

To try and eliminate the source, try putting some Wynns Hydraulic tappet fluid into your engine oil. This helps to clean out some of the crud that can cause a noisy tappet.

It helped make mine a bit quieter. I also did an engine flush on my car just before an oil change, again in an effort to flush some of the varnish and crud that builds up in a car over a period of time. Again this has helped to make the tick quicker, but its still there from cold.

My local indi says that unless the tick is constant throughout the rev range then its not worth changing them, as its quite a big job and its best to change all of the tappets all in one go as its hard to determine which one is faulty.

Coming back to the belts, as you look down at the belts are they all running nice and true or can you see the idler pulley slightly out of alignment to the belt....this causes the rubbing noise. If its out of alignment then there's a good chance the tensioner is on its way out.

By the way whats the mileage on your car......if its high and its still on the original timing chain then that could be a consideration....normally you get a clank as you start up from cold.

 

[eddie_E]

Its done 184,000 miles. It has a full MB history up until 4 or 5 years ago (it's a 94 model) and an indi history since that, so I think everything should be in order. When do the timing chains usually get changed? is it something a competent home DIY'er can fix easily enough? is it the same as changing a cambelt on a normal car?

 

[Vlad]

Hmmm.....in away it could be all three with that mileage....sorry I know thats not helping

If you have a friendly indi, I would pop the car down to them for them to have a listen and see what they say.

I'll be interested to hear the outcome

Good luck

 

[Vlad]

Sorry, I should also have mentioned that if its still on the original chain, it has in my opinion gone well over its normal service life.

 

[eddie_E]

cheers mate. I'll have a poke around under the bonnet at the weekend and try the 'pushing in the tensioner' trick to see if that gives any joy. I'll also go through the history and see if/when the timing chain was changed.

 

[Dave Lewis]

I had the same noise on my '93 E200 when I first bought it 18 months ago, at 140,000 miles. It took my local specialist about 10 seconds to diagnose it as a worn bushing on the damper, not the actual tensioner. New damper was £24.62 +vat, and new polybelt £23-34+vat. (Old one was on the way out, and it seemed a good idea to replace it while it was stripped out). Problem solved.

 

[eddie_E]

I had a quick poke about today and it went away when I pushed down on the tensioner! So it good news that it's nothing major, just need to get around to changing it now. Does anyone know if the little damper comes with the tensioner from GSF?

 

[Dave Lewis]

It's probably only the damper you need. It's the bushes in the ends that rattle.

 

[eddie_E]

Thought i'd update anyone who's interested. I sorted it with a new tensioner damper and belt. the damper didn't feel that lose but thats what it was.
Turns out it was very easy to do as well. which was nice I just unclipped the fan cowl and removerd it, got 15mm spanner on the nut in the middle of the tensioner pully and turned it CCW, the whole lot swung in which slackened the belt, was a bit fiddley to hold it over and pull of the belt at the same time but was easy enough. Then unbolted the 3 tensioner housing bolts holding it onto the block and removed the whole lot so I could get to the bolt underneath the pulley that holds the bottom of the damper on. I replaced the damper, put tensioner assembly back on, put on new belt and replaced fan cowling. job done! half hour job Max and the whole lot cost £27.45, £17.95 of that wasn't strictly nessecary but I thought while I was there I'd change the belt. All parts are top quality as well - Bilstein damper and Bosch belt. Don't let the stealers take you for a ride!