I bought a set of UPD idler pulleys and have
recently noticed noise under the hood.

I removed both pulleys and noticed that the
bearings are no longer a press-fit. Both are
loose, in the bores.

I only ran these for 7K miles. UPD warranty
on defects is only one year. I bought them
more than a year ago, so no warranty.

I did contact UPD but all I got was a spam
reply to buy a new spacer, and a “We’ve
sold these for 16 years” response.

The pulleys came with two new spacers,
and they were installed correctly.

I think they should have lasted longer than
7K miles. The supercharger pulley bearing
is really loose.

I have a video but it’s too large to post.

If I can shorten it, I’ll post it.

Anyhow, I don’t recommend UPD for any
products. These pulleys were $230+

 

Here’s a video

 

Not taking away from your post, but is it possible that the install was not done properly?

I installed their 5-piece idler pulley set myself and have been running them for over 5 years and nearly 15K - no issues at all. I've had success with their products, including the belt wrap kit they sell.

Good luck

 

”The pulleys came with two new spacers,
and they were installed correctly.”

 

After searching this forum, I saw several posts
stating failure of these pulleys at 3,000-5,000
miles. So, this isn’t an isolated incident.

 

Edited: Duplicate post

 

I bought the 5 set idler pulley (UPD) from Shardul. The reason I purchased it was it serviceability of replacing just bearings instead of replacing the entire pulley with the added advantage of a higher rated bearings. All sounds good.

I had these fixed by a Mercedes tech. It was all fine for about 40000km and one day, the pulley just snapped and broke on the highway speed of 140kph and lost all control over the steering as the belt had come off too. I was lucky as it was early morning and not much vehicles on the road and I was able to slow down to safety and call for help. My kids were in the car and it was scary. See the pics, the pulley just broke.

Contacted Shardul via email about it and sent pics, received no reply. While he wanted business, emails would be replied within a few minutes.

I had a failure of 2 other pulleys, one the bearing failed and another was wobbling - could’ve led to another dangerous incident if it wasn’t replaced. I removed all the remaining and replaced with OEM.

my opinion - upgrading to the billet pulley is not worth risking your safety. It doesn’t give any performance gain. Even if a bearing fails on one of these, it has to be removed to replace the bearings. I’d rather spend a little more and get the OEM. Since replacing with the OEM pulleys, I’ve driven over 100,000km without any failures. It’s clear to me, quality of the OEM pulleys are better and safer, it’s noisy when it fail and not snap out and putting my life in danger. My E55 is my daily driver and drive a long distances frequently, safety and reliability is crucial.

 

My upd 83mm supercharger pulley spins on the outside of the bearing. I have the 5 pulley idler set too but only installed one of them. I think I would go oem next time but genuine Mercedes were way more expensive at the time.