pesuazo

I used to own a Mercedes E420, once I purchased the serpentine belt from the dealer.......correct part number.....and about 1.5 inches short.......

rattlsnak

UPDATE..

Even though the three pulleys, (deflection, idler and tensioner) all have different part numbers, they all have the same casting number stamped on the pulley itself which made me curious. I went by the dealer today and compared them all. All of the pulleys diameters are identical as they all have the same number stamped on them.

So even though the parts catalog calls for these three metal pulleys:
996.102.117.57, 996.102.118.56 and 996.102.119.58, you can also use the newer plastic updated ones which are: 997.102.117.00, 997.102.118.00 and 997.102.119.00, but either way, all of the pulley sizes are the same. The have different part numbers because of the center type of bearing and lug positions and the tensioner is hollow.

I then went and pulled a 996 and a 997 water pump and those pulleys are identical as well.

So at this point all of my pulleys are correct. Time to measure the belt. In looking at all the reputable suppliers, it showed the belt to be 83.25 inches, or 2115mm. Mine measured out at 83" even. I stopped by on the way home and picked up another new belt (after measuring it of course) It was exactly 83.25. Brought it home and while it was still a tight fit, it slipped over the last pulley with just my hand.

ALL OF THIS OVER .@25 OF AN INCH!

Sneaky Pete

That's what she said.......glad you got it sorted out.

Ahsai

Thats too easy! Glad you get it sorted out.

rattlsnak

Yeah it does sound easy, but it is a new replacement engine to me and it had a 997 pump on it so of course I overlook the obvious and assume that all of my pulleys are wrong. Lol. If it would have been just a replacement belt that didn't fit, that would have been the first thing I looked at! Ha! Well I hope this helps someone else down the road.

TSMacNeil

Well, sorry for the runaround on the pulleys. I assumed the belt was known to be proper size.
At least you got it figured out, but I would have a conversation with whoever you got that short belt from.

alpine003

Lol was this the girth or length? Cha Ching!

OP, can you tell us what brand belt had the wrong size?

fpb111

Look at 2nd pic in post #1

Macster

Just a belt. Bad enough but it could have been much worse. Glad to read you got it sorted.

BTW, and I know this is going to read wise after the fact, but a habit of mine is whenever changing a belt to compare the old one and the new one to verify the width and length are the same.

alpine003

Gotcha, I wasn't sure if that was the original belt or the replacement.

rattlsnak

Trust me, I feel like a doofus, but the odds were against me. Remember, I just got the engine so no telling who did what to it before I got it and there was no belt on it to compare it to, so when I bought a new belt, I assumed it was good and there must be a problem somewhere else. When I noticed it had the 997 water pump on it, it sent me down the rabbit hole of pulley land.. Lol. Oh well, I certainly learned a lot!

alpine003

Thanks for sharing that with us though as I certainly myself wouldn't have expected an OEM belt to be out of spec too. This might save others some headaches down the road as I don't recall another thread like this about shortened OEM belts.

jrgordonsenior

How close are the 2 pulley now after you replaced the belt? Got pic?...

Ahsai

I'm curious too about how much diff can 0.25" make in terms of distance between pulleys.

rattlsnak

At first the pulleys were just about touching each other and the tensioner felt like it didn't release from the pushed down position and now, funny as it sounds, they are about 1/4' apart but i felt the tensioner release if that makes sense.