Screeching from A/C compressor

[Snowflake87]

Hello all,

I recently bought an 87 325e. When I bought it the AC blew hot. I looked under the hood. Determined that an R134a conversion had been done. The AC compressor hose was held on with hose clamps and the refrigerant leaked out. I replaced the hose and refilled the refrigerant and the AC worked great. A couple of weeks have passed and I have been running the AC. Before this I did not use it.

As of last week I started to get a screech at the top of the RPM range in 1st and second gear shortly after startup, but then it would eventually stop. It only happens when the AC is on. My theory, and my hope, is that I just have to tighten the tension on the belt. My thought is if it was the compressor itself would continue making the noise throughout the rpm range and the gears.

Thoughts?

[jalopi]

It's either that or the compressor clutch, tighten the belt up and see what happens

[Snowflake87]

Thanks. I'm thinking it's the belt. I've been listening to it closely.

[Snowflake87]

Ok. So I looked at it once I got off work. The compressor , seizes up and the pulley stops turning and that is when it starts screeching. Is this the clutch? Or is it the compressor itself that is screwed?

[glucklich21]

Sounds like the compressor. If it was the clutch, it would never engage the compressor.

[Snowflake87]

So I talked to my friend who charged the AC for me and sent him a video. He seems to think he overcharged the system. Gonna look at it more tomorrow.

[jalopi]

I don't know if that would cause the compressor to seize up though

[Snowflake87]

I don't know enough either way. I'm going to find out today. He's a certified mechanic so I assume he will shed some light on his theory once I meet up with him after work. Keeping my fingers crossed that it is not the compressor. But based on appearance alone it looks like the compressor haha.

[dnguyen1963]

Here is some general background for compressor...

http://www.aa1car.com/library/2003/ic50350.htm

[Snowflake87]

Thanks for the link. Very helpful, but steering my suspicions towards the worst. Arrrggg

[dnguyen1963]

yeah, I fear for you...

[Snowflake87]

Well as of right now all is good. It seems to be the overcharge. My buddy has this AC recharge tool from snap on that apparently does not work very well. So as of right now everything is good.

[jalopi]

Dude I'll be frank. Locking up a compressor from overcharging is pretty uncommon & tough to pull off... like you would have to SERIOUSLY overcharge the system... but even if you (or your friend) did do it, there is permanent, irreversible damage from doing so. Google "hydrolocking an engine", that's pretty much what happened to your compressor if this is the case.

[Snowflake87]

I appreciate the input. The compressor was not seizing for anything longer than a couple seconds at most. Once some refrigerant was removed the seizing stopped and it has been working fine since. So if and when the compressor finally craps out, at least it isn't happening now.