Need to do something about squeaky idler on 603 - Page 2 - PeachParts Mercedes-Benz Forum

Diseasel300 · #16 10-03-2019, 09:57 AM

Routing that belt and keeping it on all the pulleys is an exploration into the limits of patience isn't it?

cmac2012 · #17 10-04-2019, 09:44 AM

Quote:

Originally Posted by Diseasel300

Routing that belt and keeping it on all the pulleys is an exploration into the limits of patience isn't it?

Indeed. Was my first time. I sort of remembered the route but finding this didn't hurt:

The first difficulty was pulling it up through the water pump and crankshaft pulleys so I had enough belt to slip over the idler. That's why I made the tool. Next was figuring out which pulley to save for last. My first route was to get it on all splined pulleys and then try to slip it over the idler. That worked with the old belt but it was worn worse than I realized, was way flexible. Dumb to even think of reusing that. I didn't want to use a mere Gates from bleeping O'Reilley's, no, I had to hold out for a Continental.

Couldn't slip the Gates over the idler. So I then left the alternator pulley, the smallest for last. That was the trick. Tool 1.0 easily pulled it over that one, easily accessible and the smallest one.

Only my second vehicle with a serpintine. In my years as an E30-oholic I had much experience with removing, reinstalling, and tensing three V-belts. The serpentine setup beats that.

Carlos0422 · #18 01-28-2020, 11:59 AM

Thanks to all who regularly share their knowledge and insight on this forum. I have a 1991 350SD. I replaced the V belt within the last 10,000 miles with a Contitech. While I was attending to some basic under the hood maintenance, I noticed a strand of V belt lying in the engine compartment. Turns out the relatively new belt was separating on one side. The rest of the belt is in good shape. Could the idler pulley-tensioner lever-damper-tension spring complex make something like this happen or is it just what happens sometimes to belts? In addition, if I choose to renew these parts (as I'm sure they've been on for at least 150K miles, is the tensioner lever a difficult chore to replace? Everything else looks very straightforward but the lever looks a little more intimidating. Thanks in advance for your help.

Diseasel300 · #19 01-28-2020, 12:16 PM

Yes, failed bearings in the pulley or the tensioner pivot lever can cause the belt to come apart. The belt should last many tens of thousands of miles without issue regardless of brand. The tensioner pivot isn't hard, it's just fiddly to get out without removing the fan. Removing the fan is a major undertaking on these engines.

cmac2012 · #20 01-28-2020, 12:30 PM

I'm guessing you mean serpetine belt. It's about an inch or inch and a quarter wide, right?

Looking at the graphic in post #17, the idler wheel is the one pretty much in the center. On my car that wheel had become out of parallel with the others. Caused the back of the belt to squeak, worse to constantly scuff on the wheel. Wore it down. When I repaired my wheel's alignment I put the old belt back on - immediately one edge of it starting rolling up. I suspect it easily would have peeled off on one edge before long. I bought a new Gates, an acceptable O'Reilly's brand IMO.

Can't tell if your problem is anything like that. Look it over, show us some photos.

cmac2012 · #21 01-28-2020, 12:33 PM

Quote:

Originally Posted by Diseasel300

Yes, failed bearings in the pulley or the tensioner pivot lever can cause the belt to come apart. The belt should last many tens of thousands of miles without issue regardless of brand. The tensioner pivot isn't hard, it's just fiddly to get out without removing the fan. Removing the fan is a major undertaking on these engines.

Having the fan out is nice. This guy shows some tools for that:

https://www.youtube.com/watch?v=UwPf_sSTL7s&t=133s

Carlos0422 · #22 01-28-2020, 01:07 PM

OK. Removed the clips holding the shroud in place and secured it as forward as it would go to get some working room. Not much there but enough. Removed the fan (seems as if it was barely tightened down. The book says this bolt should be 45Nm but I'll bet it was no more than 10Nm) with an 8mm hex. As an aside, in your experience, does this viscofan ever fail? With 250,000 miles on the car, would it make sense to also replace this now? Removed the spring, the damper and the idler pulley. The pulley bearings seem OK; no leaking or dry bearing noise but they're inexpensive so this gets replaced. I removed the tensioner lever (big bolt: 12mm hex) and this is where, as Diseasel300 mentioned, I think the problem resides. The bolt threads were coated in oil (I'm assuming this isn't normal) and there's grease leaking out from the bearing seals both front and back. There is definite grinding and resistance in these bearings so this too gets replaced. I'm going to go with an MB replacement tensioner lever as this seems to be the meat of the whole system. I live in a Third World Country (New Mexico) so I may have a little time to wait for parts. What a difference a state makes: When I lived in Dallas, the local MB dealer (Park Place) had great guys working the parts counter and they could find anything. Even the most esoteric parts for a 30 year old car would get to me in 2 days. Thanks to all for your help.

Diseasel300 · #23 01-28-2020, 01:21 PM

Save the big washer on the back of the tensioner pivot. You'll need to swap it to the new one. It is EXTREMELY IMPORTANT. If you leave it out, you will break the timing cover (VERY EXPENSIVE).

The fan clutch does take a dump with time. Don't bother replacing it with a 603 style, buy a clutch and fan blade for a '98-99 E300TD. Not only are the parts cheaper, but the 11-blade fan moves a bit more air and helps with temperature leveling and A/C performance.

Carlos0422 · #24 01-28-2020, 01:54 PM

Thanks for the heads up on the washer. I thought it was just a bearing cap. Had to pound the bolt out to get it to dislodge but I will be careful to make sure I get it on the new lever.

Carlos0422 · #25 01-28-2020, 01:59 PM

Another quick question. Someone long ago decided that there was no need to replace the sealing caps on the tensioner lever and the idler pulley as they are long gone. In your opinion, how important are these sealing caps?

Diseasel300 · #26 01-28-2020, 02:16 PM

The caps keep rain and grit out of the bearings. If you want them to last as long as possible, the caps are a good idea to replace.

Carlos0422 · #27 01-28-2020, 02:24 PM

Those two little guys will be the hardest to track down I'm sure. Thanks for all of your help.

Diseasel300 · #28 01-28-2020, 03:40 PM

All of the parts needed to upgrade/repair the tensioner are available right here on the host's website, including the pulley caps.

barry12345 · #29 01-28-2020, 04:45 PM

Really nice to see the details being covered on issues. Unfortunatly the devil is in the details is a real issue.

I just wanted to mention. Although I think you did.. To use blue locktite where it was used originally.

Personally I use laquer thinner to clean off any bolt threads and threaded holes or nuts first. As it dries so fast and leaves no residue. I so far have never found any solvent better for this.

Thread lock applied to dirty or oily threads is undesirable. If not unacceptable. I have over the years found so many uses for it. I always keep it on hand. It is very flameable though. Concentrated fumes can also make you high. A bonus I wonder? They have to be pretty concentrated though. Gun wash, a lower grade of it is the cheapest. It is more than adequate. Local sources are usually auto body supply places.

Gun wash grade is only availabe in five gallon containers in Canada. Yet may be in smaller quantities in America. Brake cleaner is perhaps another product to use. I do not know if it is as good though. To me it also dries fairly fast but still noticeably slower.

If a bolt is known to back out of an application. It is absolutely mandatory to stop a repeat performance. That is why auto manufactures ask you to use new bolts in some cases. They know you will do this as the bolt is pre coated with thread locker. Some of those bolts are not stressed in service I did not believe personally. So I assumed right or wrong it was the thread locker issue.

Carlos0422 · #30 01-28-2020, 06:44 PM

More great help. I like the lacquer thinner idea a lot. Lots of folks go for the brake parts cleaner but that stuff scares me. I'm sure that's what did the dinosaurs in. The service manual calls for Omnifit 100 M Orange as a thread locker but I think the company was bought by someone at some point. In any event, the Omnifit product, from what I can tell, was an anaerobic medium strength product. Vibra-Tite makes the same thing labeled as #121. It's their blue medium strength threadlocker and it happens to be anaerobic too. Imagine my surprise. I always use this where applicable. Thanks for your insight.