# Serpentine Belt Proper Tension on 190D 2.5 **URL:** \ **Category:** General Discussion\ **Tags:** mercedes-benz, 190\ **Created:** [October 27, 2012, 6:10pm UTC](https://community.cartalk.com/t/serpentine-belt-proper-tension-on-190d-2-5/75194 "2012-10-27T18:10:55Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![OldDieseler](https://avatars.discourse-cdn.com/v4/letter/o/5daacb/32.png) [@OldDieseler](https://community.cartalk.com/u/OldDieseler)\ **Post date:** [October 27, 2012, 6:10pm UTC](https://community.cartalk.com/t/serpentine-belt-proper-tension-on-190d-2-5/75194/1 "2012-10-27T18:10:55Z")
How do I know if my belt is a little loose? My tach and a/c die intermittantly and I’m thinking the belt might be slipping. It seems old and it flaps a at the top at idle but not when reved higher. Can this be adjusted by moving the alternator? ---
**Author:** ![jtsanders](https://avatars.discourse-cdn.com/v4/letter/j/c2a13f/32.png) [@jtsanders](https://community.cartalk.com/u/jtsanders)\ **Post date:** [October 27, 2012, 7:55pm UTC](https://community.cartalk.com/t/serpentine-belt-proper-tension-on-190d-2-5/75194/2 "2012-10-27T19:55:15Z")
Push on the belt between two pulleys. If you get more than an inch or two deflection, it is too loose. Just get a new one and replace the old one. ---
**Author:** ![old\_544](https://avatars.discourse-cdn.com/v4/letter/o/ac8455/32.png) [@old\_544](https://community.cartalk.com/u/old_544)\ **Post date:** [October 28, 2012, 4:15am UTC](https://community.cartalk.com/t/serpentine-belt-proper-tension-on-190d-2-5/75194/3 "2012-10-28T04:15:56Z")
belt tensioner and shock were common wear items on the 190’s. the a/c clutch was equipped with a “slippage” device that would turn off the compressor if belt slippage was detected. Chances are that you need a tensioner. The belt shock made a chattering sound at idle when replacement was needed because the bushing end wore out where it bolted to the engine. Great car though. The 2.5 was a really gutsy little diesel that was a lot of fun to drive, especially with the 5 speed. ---
**Author:** ![beeblmeyer](https://avatars.discourse-cdn.com/v4/letter/b/3da27b/32.png) [@beeblmeyer](https://community.cartalk.com/u/beeblmeyer)\ **Post date:** [October 28, 2012, 5:39pm UTC](https://community.cartalk.com/t/serpentine-belt-proper-tension-on-190d-2-5/75194/4 "2012-10-28T17:39:27Z")
Funny timing of this notification. Just this past week I had my belt, tensioner and shock changed on my 1988 2.6 190 E with 96,000 original miles, because my car was behaving the way you describe, but I think my belt was a little further gone. Mine got to the point where it would squeal like a heard of stuck pigs for about the first five humiliating miles, then quiet down. I was told by the first mechanic (small shop) I took it to that the job required two specific tools, which he didn’t have because they cost about $600. Being in a smaller city with few options, he recommended I take it to the dealer. 3.8 labor hours, and a little over $400 for the parts. Out the door was about $950. So I’m hoping to not have to worry about it for another 96,000 miles. Good luck!