air conditioning issues/ Bypass pulley? - Diesel Forum

bcreighton7 · 11-16-2009, 08:13 PM

I hadn't been paying to much attention to the little burnt smell I've sometimes had the last two weeks, but last time I ran the heat, a strange noise seemed to be coming from my truck.
Anyway today the a/c seized and burnt the belt. I was told that I couldn't change the bearings, but just had to get a new compressor. I've learned this is probably wrong. So not wanting to shell out $400 for a new compressor right now, and no local junk yards having one for immediate pickup, I put on a bypass pulley. But I made the probable mistake of disconnecting the compressor. It seemed probably fully charged.

1. Does it seem worthwhile to try a new clutch?

2. So now the thing makes a loud squeak or chirp sound, which turns to a grinding sound at 2000 rpm plus. I guess this is probably the vacuum pump. How can I bypass this or get back on the road?

bcreighton7 · 11-16-2009, 08:14 PM

Oh, and disregard my signature. This is on my 95 F250 Powerstroke.

bcreighton7 · 11-16-2009, 08:32 PM

The pulley froze stiff. This is why the belt burnt. I've read that if the pulley will turn, then the compressor is probably toast, but if the pulley freezes, it is probably the ac clutch. Please help!

444-4D · 11-16-2009, 08:40 PM

If the pulley won't turn you have a bad pulley bearing. If the compressor clutch plate won't turn you have a bad compressor.

bcreighton7 · 11-17-2009, 12:17 PM

Thank you for your reply. I had already done a search, and I think it was you who said something similar.

They are both frozen. The pulley is definitely toast. It is no longer straight. The clutch plate doesn't turn, but maybe the pulley has somehow affected it. However, my guess is the compressor is toast, and that is why I had noticed the smell.

So now I need to find out what is making the noise, and how to stop it.

bcreighton7 · 11-17-2009, 12:18 PM

It didn't make this noise when the belt was burning, and didn't make the noise after the belt broke, and I drove it to Napa to get a new belt.

bcreighton7 · 11-17-2009, 03:13 PM

Well, thanks again. This one is resolved. Once I got into it more with the stethescope, it didn't seem like the vacuum pump was making the noise. I could see the belt slipping on its pulley, so I put spacers in to tighten the belt - noise went away. Feel stupid now, but no one else has to help with the problem anymore.