W123 300DT A/C idler pulley? - PeachParts Mercedes-Benz Forum

PerkHouse · #1 07-20-2013, 01:21 PM

Hi guys,

Long time... i've been in China for 10 months riding my bicycle and electric scooter (I love that thing!), but I just got home to work on my baby (300D) some more. I completely rebuilt the A/C last summer, but shortly after I left for China, my daughter reported that the A/C quit working. When it got colder outside, she also told me the heat didn't work. Now that I'm back I've discovered that the climate control is completely dead and I suspect the wiring harness to the ignition as the culprit, but that's not the reason for my post.

Out of curiousity, I popped the hood to check the static pressure on the refrigerant to see if there were any leaks and was glad to see it was right where I left it 10 months ago. However, I noticed that the A/C belt is extremely loose (about 3/4" maybe even 1" of play) and the adjuster is maxed out. Confused, I wondered if maybe I missed something last summer when I happened across an advertisement for a replacement A/C idler pulley (MB 116 130 04 60). However, the old A/C system on my car didn't have an idler pulley, but that would certainly explain my loose belt.

Do any of you guys with early-mid 80's 300D's have an idler pulley on your A/C belt???

Phillytwotank · #2 07-20-2013, 01:59 PM

No idler pulley there. Sounds like you're going to have to get a new smaller belt.

PerkHouse · #3 07-21-2013, 02:57 PM

I did some more digging and it seems that those who got the steam engine (aka York) compressor had an idler/tensioner, but not the Delco R4 compressor.

Weird! I have now taken the mechanical mounting system nearly apart (without breaking the refrigerant system open of course) and it seems like I might be able to slide a spacer up in between the block and the carrier bracket, but I can't see for sure if there are any protrusions that will interfere.

I can't remember which company makes this particular belt. I think it's either a Meyle or Behr. But maybe the solution is as simple as a new belt. I guess it's time to pull the power steering belt.

If a new belt doesn't solve that problem, then I may try to shim the carrier out about 1/4" which should more that take up the 3/4" of play in the belt. I just dread removing the compressor from the carrier and then dangling it in the way with chains or whatever while I try to refit the carrier. Eeek!

PerkHouse · #4 07-22-2013, 10:32 PM

Well, I removed the new belt and installed a new, new belt today. Instead of getting an expensive German import, I got a cheap Chinese import. (Actually, I don't know where the DuraLast belts from Autozone are made.) The new belt is a #17365 and the new, new belt is also a #17365, but the newer one was significantly shorter than the one that only had a month's wear on it.

C'est la vie!