Troubleshooting Compressor Failure

[Stripped66]

Later this month, I'll be installing my van's 4th (at least...) A/C compressor. I bought the van with a failed compressor; the PO claimed the compressor locked up.

I replaced that with a cheap-o new replacement (and new receiver/drier and oil - PAG 150) and it lasted about one month (~3K miles) before it ate its valves. I did not flush the system, so I suspect debris was the cause of the compressor damage.

We were halfway through a cross-country road trip when that happened, and fortunately my friend's business in Portland has a division that does A/C (auto/fleet and commercial truck), so his tech and I flushed all lines, and both evaporators, and replaced the condensor, expansion valves, receiver/drier, and installed a new Sanden compressor. It lasted about 3.5 months of occasional driving (~4K miles) before the compressor ate its valves.

I'm not confident debris was to blame for the last failure. We used a lighter-weight PAG oil than the original PAG 150 (perhaps, PAG 100 or 46...cannot remember)...whatever the spec was in Alldata, and after several calls to the local VW dealership could not confirm whether the correct weight was the original 150 or the new spec in Alldata, we went with the lighter oil.

Is it possible the lighter viscosity oil could have led to oil accumulating in the compressor and leading to the broken valves? And, any thoughts on the new PAO 68 oil that Behr claims is a replacement for all PAG oil weights?

Finally, I plan on installing this next compressor with an Airsept Compressor Guard (https://www.airsept.com/Products/Details/32) screen on the low-pressure inlet...I figure that is cheap insurance if there happens to be debris remaining in the system (because if there's debris in the evaporators, it's nearly impossible to flush it out, and I'm not replacing those).

Other thoughts? Between my 4 aging German cars, I'm doing way too much A/C work to not be getting paid
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[Abscate]

If you get them from FCP, they have a lifetime warranty, at least.

If the old compressor cratered and fragmented, you need to replace evap and condenser, and receiver - possibly Expansion valve too. Especially true if you have rear AC option on your T4
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.ssS!

[Stripped66]

[Abscate]

As the Bears say...

Oh, I didn’t know that...

7D1820011A Is DISCONTINUED per VWOA

Maybe we can get it in EU?

I’m in Munich next week and can check parts places
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.ssS!

[CdnVWJunkie]

[Stripped66]

[Stripped66]

Posting this just for grins and giggles...

I hoped to have this all back together next week...Trying to get an update from the Latvians on the shipping status of the replacement evaps.
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[Stripped66]

Not shipping until Monday...takes them 2 weeks to dispatch the evaps, plus who knows how long en route. Maybe end of the month if I'm lucky? Oh well...road trip to Glacier isn't happening this year
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[volkybus]

well those compressors r tricky...on my 93 itwas making noise so I freed it u[p and it lasted only 1.1/2 weeks freewheeling...no AC ...well it siezed up and had to be towed home....anyway the compressor and clutch locked up and the engine would not turn over...I replaced the compresser with a used one now all is well...when I get back to the van...its in PR..Im up north now I may or may not charge it.Anyway the question is do we really need all that modern stuff on old VWS??? is it really worth it???? I have 4 old vws on the road and not one has working AC...anyway good luck....Bill

[Stripped66]

Running your compressor dry until it seizes isn't tricky.
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[volkybus]

yep but AC is overrated.....and if you want a modern car w all the modern gagets just buy a new car....a classic is old and special and maybe by expecting a 25-50+ year old car to be the same as a new minivan or whatever I think you are missing the whole experance...anyway that,s my opinion..l..anyway anybody going to the big VW van campout its in Townson Vt this upcoming weekend...IT WILL be all vw busses from barndoors to new t/6 from Europe text me 4 directions 802/683/0872....Bill

[Stripped66]

Should I put a carburetor on it, too? 'Cuz it's a "classic"?
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[volkybus]

that my friend is up to you...fuel injection is great till it breaks then good luck....this is a help collum so please be helpful and not sarcastic...well off in my non airconditioned and carbed bus to go sailing....its 90+ so air would be nice today...

[Stripped66]

[Stripped66]

The "new" evaporator:

Spent a bit over 3 hours straightening the fins

After a bit of tweaking, I got it back into the housing and reinstalled the front HVAC unit yesterday. I vac'd down the A/C system today to check whether there were any leaks in the evaporator from damage unseen...it held a vacuum all day I spent the rest of the day reinstalling the dash:

It's always nice when everything works once it's all back together.

If it's still holding a vacuum tomorrow, I'll install the new compressor and receiver/drier, distribute the oil, vac once again and then charge the system.
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