AC belt keeps popping off

[Geotrash]

Here’s a good one for y’all. Earlier this winter while we were up skiing at Snowshoe, I noticed that my AC belt on my 2007 had jumped off and was just hanging from the crank pulley. Over the past year, I had noticed some pretty harsh engagements of the AC compressor up to when it threw the belt so I replaced the compressor, the belt, and the tensioner myself after having a shop evacuate the system.

Fast forward to last weekend, and we had driven to Durham, North Carolina, and I just happen to check under the hood as I sometimes do, and noticed that the AC belt had jumped off again, and was hanging around the crank pulley like before.

And the only thing I can think of is that because the compressor is so low, that it’s developed a slug of oil that takes a while to get moving if it’s been sitting for a few days. When I replaced the compressor, I followed the procedures of the compressor manufacturer, and it was one that came with the PAO oil pre-filled in the correct amount, so I didn’t add any more. I charged up the system, and it was running perfectly.

Then, I noticed that I had a leak in one of my Schrader valves, so I took it to a local shop and had them evacuate the system properly and replace the valve, then recharge the system. However, when I picked it up, the shop owner told me that they added the appropriate amount of oil to the system. I didn’t go ballistic because I should’ve been clearer in my instructions when I dropped it off, but whatever.

Anyway, I’m wondering if I still have a slug of oil in the system that’s causing the compressor to momentarily hang on engagement sometimes. Anyone else run into this?

I see that there’s a company who sells a little gadget called the deslugger, designed to ease the clutch engagement on the compressor. I ordered one, and plan to install it to see if it will help.

Edit: after more reading, it's possible that my accumulator is going bad. Dammit.

 

[pwtr02ss]

I had a Camaro a long time ago that would do that. Turned out to be the harmonic balancer walking out. I replaced the bolt and never had another issue. I doubt that's your problem but its worth a look

 

[gooffeyguy]

Here’s a good one for y’all. Earlier this winter while we were up skiing at Snowshoe, I noticed that my AC belt on my 2007 had jumped off and was just hanging from the crank pulley. Over the past year, I had noticed some pretty harsh engagements of the AC compressor so I replaced the compressor, the belt, and the tensioner myself after having a shop evacuate the system.

Fast forward to last weekend, and we had driven to Durham, North Carolina, and I just happen to check under the hood as I sometimes do, and noticed that the AC belt had jumped off again, and was hanging around the crank pulley like before.

And the only thing I can think of is that because the compressor is so low, that it’s developed a slug of oil that takes a while to get moving if it’s been sitting for a few days. When I replaced the compressor, I followed the procedures of the compressor manufacturer, and it was one that came with the PAO oil pre-filled in the correct amount, so I didn’t add any more. I charged up the system, and it was running perfectly.

Then, I noticed that I had a leak in one of my Schrader valves, so I took it to a local shop and had them evacuate the system properly and replace the valve, then recharge the system. However, when I picked it up, the shop owner told me that they added the appropriate amount of oil to the system. I didn’t go ballistic because I should’ve been clearer in my instructions when I dropped it off, but whatever.

Anyway, I’m wondering if I still have a slug of oil in the system that’s causing the compressor to momentarily hang on engagement sometimes. Anyone else run into this?

I see that there’s a company who sells a little gadget called the deslugger, designed to ease the clutch engagement on the compressor. I ordered one, and plan to install it to see if it will help.

Edit: after more reading, it's possible that my accumulator is going bad. Dammit.

I installed a deslugger about 4 years ago and removed it 3 years ago. Currently sitting in the parts bin in the garage.

I think it's beneficial on a new compressor, but on my not new compressor it just seemed to be a bit annoying and probably not helping any

 

[donjetman]

@Geotrash said: Anyway, I’m wondering if I still have a slug of oil in the system that’s causing the compressor to momentarily hang on engagement sometimes. Anyone else run into this?

Sounds like it to me.
or
The harmonic balancer is slipping on its hub and needs replacement

 

[OR VietVet]

I would be more worried about belt alignment. You said you did compressor and tensioner and the only other place the belt runs is the crank/harmonic balancer. Get in there and check it all out.

 

[Geotrash]

I had a Camaro a long time ago that would do that. Turned out to be the harmonic balancer walking out. I replaced the bolt and never had another issue. I doubt that's your problem but its worth a look

Aight. I agree it's worth a look. I have an extra ARP balancer bolt too from another project.

I installed a deslugger about 4 years ago and removed it 3 years ago. Currently sitting in the parts bin in the garage.

I think it's beneficial on a new compressor, but on my not new compressor it just seemed to be a bit annoying and probably not helping any

Huh. What was annoying about it? Were you having problems like harsh compressor engagement or anything?

@Geotrash said: Anyway, I’m wondering if I still have a slug of oil in the system that’s causing the compressor to momentarily hang on engagement sometimes. Anyone else run into this?

Sounds like it to me.
or
The harmonic balancer is slipping on its hub and needs replacement

Thanks Don. I'll definitely check the balancer bolt and maybe the deslugger will help.

I should also note that both times when it threw the belt *I think* were after hard accelerations to high RPMs. After doing some more reading, it's possible that the accumulator is getting weak and letting too much refrigerant and oil through to the compressor at higher RPMs.

 

[gooffeyguy]

Huh. What was annoying about it? Were you having problems like harsh compressor engagement or anything?

The AC would just seem to cut in/out for the first minute or so after starting. There would be cold air, then not cold air, and it seemed to cycle on/off for a bit.

I know the deslugger is supposed to cycle the compressor on/off very quickly when starting up, but it just seemed to do it longer than I expected.

 

[Geotrash]

The AC would just seem to cut in/out for the first minute or so after starting. There would be cold air, then not cold air, and it seemed to cycle on/off for a bit.

I know the deslugger is supposed to cycle the compressor on/off very quickly when starting up, but it just seemed to do it longer than I expected.

Thanks for that detail. I think I’m gonna install it to see if I can keep it going without damaging it until I can have it evacuated again and do the accumulator and orifice tubes, etc.

My wife is going to be taking a road trip with it next week.

 

[Foggy]

Def look at the alignment and balancer.. I don't think the "deslugger" device
would help your issue at all.. I did a bunch of research on it about 3 years ago,,,
but after my self education I decided against it... It's really just supposed to help
the life/longevity of the compressor... No other real benefits that I could find
I bet your balancer has "slipped" and causing an issue.. Also check the bolts
and the actual mounting of the compressor itself.. if its off even a hair it will throw belts

 

[CorvairGeek]

This may or may not be your issue, but there is a known slugging issue with low mounted compressors, thus the reason for the "deslugger" and the rolled on belt with no tensioner. The description from a former Delco engineer on how and why (and why so infrequent too) was fascinating. I won't even try to give his explanation.
There was a known issue with slugging on high mounted (R4) other GM bodies clear back in the 80s too. No idea why on those. Makes more sense on a low mounted one that ends up full of liquid refrigerant.