klonsbury

I've searched and can't find the answer. In another forum, it mentions removing a bolt near the tensioner pulley and then the tension will actually move. Thus allowing the belt to come off. Is this correct?

Thanks!
Kyle.

quaalude

On the M113 V8, the tensioner has a 17mm bolt that you use to pivot the tensioner. Put a socket with breaker bar or socket, ratchet, and long pipe on the bolt and rotate the tensioner counter-clockwise and remove the belt. Everything can be done from up top. No need to remove any bolts, at least on the M113.

klonsbury

Thanks Quaalude! I'll try that out tonight.

Rudeney

I can usually replace it without any tools - just pull on the belt and the tensioner will give enough to slide it off the water pump pulley. Same with putting it back on - route it on everything but the water pump, then pull it onto the water pump.

klonsbury

Belt replaced!

Spark plugs are up next. Anyone know what gap is best?

Rudeney

If you get the proper plugs (Bosch), they come pre-gapped (Oh and torque is 23Nm).

lars

Is there a recommended mileage interval for the belt replacement?

Rudeney

Just check the belt for cracks and wear at every service. Environmental factors will have a lot to do with its lifespan, but 100K miles is not unusual.

lars

Thanks!

bheng

does anyone know if this is the same on a m112? hopefully easier because I have more engine bay room =D?

Rudeney

Almost identical on the M112 - and yes, easier as there is more room to work.

Dimitri

Im also need to change my belt, what is the OEM brand and part number for it? I have 2004 CLK500

Rudeney

I don't know who the OEM is, but the MBZ part number is A0159972592. Honestly I'd probably just buy a good quality aftermarket belt from a retail auto parts store - there's not a lot to belt technology.

faran

Sorry for bring this thread back from dead, but I am at ~78k miles and think on the original belt.

I don't see any cracks or anything but thinking to replace as a precautionary measure. Is it really that easy without opening that 17mm bolt? Should I also replace the tensioner too or just the belt? No noise or anything so far.

One more thing, is water pump right above crank pulley or?

gixxerboy

no real reason to replace it if there are no cracks but yes its that easy. I wouldn't replace the tensioner just to replace it

faran

Thanks for your advice. I'll hold on to belt for sometime then. No tensioner for me, just the belt it is.


Thank you

clydem

My wife is cracking 100K and the belt looks fine.

faran

Is it from 2004 or 2005 and an OE belt?

clydem

2005 & Original.
But if the belt gets replaced (thinking about it) so would the tensioners.
The only belt I've ever seen NEED replacing was my old '73 Pinto. It had a cut in it.

faran

Makes sense, please do post here if you end up replacing tensioner and which ones would you replace? Just one or any other?

gixxerboy

why would you have to replace the tensioner? its hydraulic so unless that part has failed or the bearing in the pulley itself there is no need. Rubber cracks with age, its a part that eventually you have to replace, the tension er may never need to be replaced.

Rudeney

The tensioner uses a spring - not hydraulics (though 4MATIC models do have an additional hydraulic strut in addition to the tensioner). The spring rarely fails, though I did have one do that on my C240. It's symptom was a "clucking" noise when the power steering pump was stressed by tight turns.

Typical problems of the tensioner and the idler pulleys are bearing failure. This will be a squeaking noise. When this happens, replace the pulley because it will eventually lock-up and destroy the belt. Another failure is if these plastic pulley crack. That can also shred the belt. That also happened on my C240 and the strips of belt got sucked into the alternator. It took me an hour to unwind all the crap.

When you have the belt off, inspect the idler and tensioner pulleys for any cracks. Rotate them to fell for bearing wear.

faran

Thanks so much GB and R.

I am going to hold on to this belt for now and will look and keep an eye to see if it's falling apart, then will replace it.

When no belt would be there, will check for any abnormal noises on the tensioners too, as well as plastic pulleys.

Thank you again.

faran

Thanks Rodney. Is it possible for you to share a picture of the pulley/tensioner which can fail or has a possibility of bearing failure? Is it the one with 17mm screw on it? Or the one on the front of the engine with a really long bolt?

So far there is no squeaking or any other noise, does it mean things are good for now?

Rudeney

Refer to this:

http://benzbits.com/M112/BeltRouting.pdf

#4 is the idler pulley. When you replace it, you just remove the Torx bolt and swap the pulley with integrated bearing. #7 is the tensioner pulley. It's replaced as an entire assembly.