Chevy AC Delco A/C underperforming


LawnSite Member
Clearwater, FL
I just purchased an '83 Chevy G20 conversion Van w/ a 6.2 diesel engine. So far I love this beast, but I'm somewhat disappointed with the A/C (I live in FL and it's a MUST!). The A/C doesn't seem to get very cold and only improves somewhat when it's rolling at 50+mph or when accelerating hard and the rear air doesn't seem to be working at all. It was converted from R12 to R134a and (supposedly) has a new compressor and dryer. I was told that Chevy / Delco AC systems don't cool as well as those from other mfg's. Is there any truth to this? ANY troubleshooting input regarding this (what to check first, possible upgrades, ideas, flat rate fees, etc.) would be greatly appreciated.


LawnSite Senior Member
I have a 1996 Pontiac Bonneville, ( OK, so I don't hear any flack.. I know it isn't a Chevy Truck, but it has great bucket seats)

Anyway, the A/C was acting up, so I too it to a GM dealer... they told me it was a bad compressor and that it would cost somewhere between $1,000 and $1,200. I went and got a second opinion, from someone else I knew... Turned out to be a blocked orifice tube. The repair cost about $150.

be careful and always get a second opinion. You wouldn't want to get a heart transplant if all you needed was an antacid tablet, now would you?

Chuck Smith

LawnSite Senior Member
Nutley, NJ
One other thing to keep in mind, is that the new R-134a doesn't cool nearly as much as the old R-12, especially when you convert a system.


John DiMartino

LawnSite Silver Member
R134 has a 90% heat transfer in comparison to the R12 that it was built for.Newer trucks have thicker condensor and evaporator units to compensate for the inefficient 134A's heat transfer.It is possible that you have a plugged orrifice tube too,there is a screen that stops chunks of metal from the compressor from lodging in ther orrifice,if the compressor is going out or it had a compressor failure in the past and it wasnt flushed properly,the chunks of metal could totally block the orrifice tube,almost stopping the system from working. Curtis-you do have a bad compressor-the orrife tube didnt get blocked up from nothing-the compressor is coming apart-it may last a little while,but it will fail and it is loading up the whole system with chunks now,so it wil block again soon.then you'll need a whole new system to get all the crud out.


LawnSite Senior Member
John D.

I know, but the idea of having to replace an AC unit on a car that is 4 years old and has 40,000 miles just ticks me off.

and then Detroit people wonder why alot of Americans buy foreign cars!

Yes, the compressor is going to have to be replaced at some point. I know it. But if I have to change the orifice tube again, then I will consider changing the system or maybe trading the car in.

Let the dealer repair it then resell the vehicle.

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