New to the SRT-6 but while doing service I noticed the belt had cracks, I was thinking of going with a different pulley and wanted to know if I would need a different belt when doing that mod or will use the stock size?

 

Why would you want to change to a different pulley/belt. Serpentine belts are very strong and if the belt is showing small wear cracks on the peaks would probably be considered safe wear. The strength is in the belt itself not the little groves. Just an opinion. Belts are cheap so if it worries you change it with new belt.

 

The belt tensioner on MY car has a lot of travel - I refuse to believe that a pulley of maybe 9mm less would mean you need a shorter belt!

As to cracks, SMALL cracks are considered normal wear. On the OTHER hand, I don't think I've put more than 30,000 miles on a belt in the entire time I've owned three N/A Crossfires. I don't allow simple, cheap and easy-to-replace items to become a cause for walking for parts.

 

Ok, started up the XF today and the belt has come off and the battery light came on. Do you normally change the pulley and or tensioner and the belt at the same time as preventive?

 

If you can afford it, it sure wouldn't hurt.

 

Now that the belt is off, spin each idler and tensioner pulley checking for roughness/noise. Replace what you find and the belt.
I am assuming there was no oil on the belt, right ?

 

See George's questions above about oil, etc.

I change my belt, like I said, given how few miles I put on the car, every 4-5 years (30,000 miles or so) but unless I'm having a problem or hearing noises, I dont go farther than that.
I DID have a belt tensioner go on the Graphite, it was making all sorts of noises, LOUD noises. I changed it and the idler pulley at the same time (idlers tend to fail, too). But I didn't change pulleys until I hear odd noises or notice shaking or wobble in them with the engine idling.

 

From what you say the belt just came off while the engine was stationary. Strange, have you looked for the reason?

 

Hi onehundred80, pizzaguy, ala_xfire and ZERACER, thanks for the replies, the belt is split down the middle and had signs of a another tear developing on other parts of the belt also in the middle. I was backing out the driveway at the time when it occurred so it is parked in the front yard now while I wait for the gates belt to come in. I will check the idler for any play as well as the tensioner and if replacement is necessary then I have spares of both.

 

Where do you live? I've owned Crossfires while living in GA, TX and AR. I have always found a belt at Autozone/etc. Just tell them it's a 2003 SLK320, same engine, same belt.
(If you say Crossfire, some parts books give a different part number for the same part - that "Different" number won't be 'in stock' but the '320 version will be, as it is prescribed for several MB products with the M112 engine.)

 

Good advice from pizzaguy on part searches for the Crossfire. Much easier to locate parts for the M-B powertrain & rolling chassis which are the same as the Crossfire. The engine was widely used across several M-B models, which makes parts more available.

I visually inspect the serpentine drive belt every 6-9 months looking for signs of wear. And if small cracks are visible, I will install a new belt in the near future. The idler & tension pulleys most likely would also be changed out. Just not worth the risk from a reliability perspective.

 

Thanks pizzaguy and dedwards0323, live in FL and yes had purchased a Dayco from Autozone about 3 years ago which was the one that failed on me, so got the Gates belt yesterday and will install. Thanks for the suggestion on the MB parts. I tend to forget sometimes

 

Well the Gates belt failed, split down the middle happened when I was pulling into the driveway tonight. So tomorrow, I will go back to the Dayco since that lasted more than than the month I had the Gates belt. Just SMDH....

 

That's pretty strange occurance. When replacing the belt, this time, look for a mechanical malfunction or alignment problems.

 

That seems extreme - I'm questioning if one of the pulleys is not aligned right - have you had anything replaced lately? I'm thinking belt tensioner, alternator, etc.
Something is way wrong here, I've been an owner and member here twelve years, some of us (not me!) go YEARS on a belt and they don't fail.


I sense there is something under the hood that is not right here!

 

Belts have split when the belt was not fitting in all the grooves, it being one groove over on one pulley. The belt is stressed too much and splits.

 

Thanks for all the replies, no have not changed anything recently but like onehundred80 states maybe the belt was not fully on all the pulley. I will double check to make sure that all looks ok when I change it today. Autozone only have the Continental belt, they no longer carry Dayco.

 

At least both times it happened in your driveway. Definitely check the idler pulley it has been splitting/breaking in the middle for forum members. Gates is the manufacturer of the Mercedes belt so I do not think that is the problem. Also check the tensioner and possibly replace it depending on how many miles you have.

 

Hi Ronman, thanks for the response the tensioner was replaced either 2017 or 2018 and it's not a daily driver maybe about a 2K miles a year if lucky. I will check the idler pulley as that is original but doesn't seem to have any play in it or squeals. Will replace that as I am thinking about it. It is feasible I guess that the tensioner could have also gone bad but no symptoms based on spinning etc.

 

How many total miles? Idler pulley is the first one to go usually. When you changed the belt recently, was it really easy to release the tension on the tensioner? Was it real easy to put on the new belt? If so, then the tensioner might be the problem. Good luck.