Help upgrading the AC on a 1985 C20 6.2L

[1987 GMC Jimmy]

^^^ That's what I was thinking.

 

[Blue Ox]

True, the original condensers on these things were overkill. My 'burb with dual A/C had the same condenser as the pickup and it made some serious cold.

Just be careful about the R12. It's not illegal to use it, but since the manufacture was banned you need to find someone who is recycling it properly or a reliable source. Unfortunately there are a lot of people mixing it with other refrigerants or propane and marketing it as straight R12. A good shop will have an identifier that can sniff out the questionable stuff.

 

[Matt69olds]

The A6 compressor is oversized and overkill for a car or truck. When I went thru GM training center A/C class the instructor told us the compressor had sufficient capacity for a small house. Having said that, it’s also a very durable compressor, it has its own oil supply in the sump. The R4 compressor isn’t as durable, but doesn’t take nearly the power to run that the old A6 does.

The 134A refrigerant isn’t as good as the old R12, but with the overkill A/C designed into these tricks, it is still plenty good. Replace the confessor, replace the orifice tube, vacuum the system, install the correct oil charge (it will be included with the 134A conversion kit) and recharge. Make sure the fan clutch engages, and enjoy the comfort of modern convenience

 

[bucket]

I've been happy with the stock AC in mine, even with the R134 juice. Especially the Burb with dual AC, the kids would often whine at me to turn the AC down, even in August.

 

[5akman]

The A6 compressor is oversized and overkill for a car or truck. When I went thru GM training center A/C class the instructor told us the compressor had sufficient capacity for a small house. Having said that, it’s also a very durable compressor, it has its own oil supply in the sump. The R4 compressor isn’t as durable, but doesn’t take nearly the power to run that the old A6 does.

The 134A refrigerant isn’t as good as the old R12, but with the overkill A/C designed into these tricks, it is still plenty good. Replace the confessor, replace the orifice tube, vacuum the system, install the correct oil charge (it will be included with the 134A conversion kit) and recharge. Make sure the fan clutch engages, and enjoy the comfort of modern convenience

Any idea what model Sanden compressor is a direct swap for the A6? I've read through many threads but never see any mention of a model to model part number for the swap.

 

[75gmck25]

Vintage Air sells a Sanden compressor and bracket that bolts on to your engine, but it has standard (#10, #8) fittings on the back. However, on many Sandens you can buy a replacement "block' for the back that has different fittings, or you may be able to get adapters to use your old hoses. Also consider that old hoses may not be barrier hoses, which are recommended with R134a

The old A6 compressor is a true boat anchor, and the rebuilts are unreliable; however, there is a Pro6Ten compressor (https://www.oldairproducts.com/product/21-2201sh-pol-compressor) to replace it, which is apparenly a Sanden in a form factor that matches the A6.

On my truck I replaced the A6 with a Sanden and new brackets (Vintage Air), used a new parallel flow condenser (Arizona Mobile Air), Ford blue orifice (local part store), and new GM filter/drier, and had custom hoses made by a place in San Antonio (they charged me about $130). I also switched to PAG oil, and used R134a at about 75% of the R12 charge.

My suggestion for a basic upgrade: Replace the compressor, filter/drier, and orifice, flush the condenser and evaporator to get all the old oil out, and replace all the O-rings. Vacuum and recharge with PAG oil and R134a, and you will probably be happy with the results. Make sure your OEM metal fan and shroud is working well to get good condenser air flow. You might want to upgrade to an HD clutch for the fan.

Bruce

 

[Craig 85]

I haven't got to the point of restoring my A/C, but I found this Sanden style compressor that bolts in place of the A6 using OEM brackets (16 LBS vs. 34 LBS). It is a Four Seasons #58096. They range in price from $250-300. They also list #58098. The only differences I can see between the two is the type of switch. The 58096 is a high pressure; the 58098 is a super heat. I couldn't tell you what a super heat is though. Also the clutch diameter on the 58098 is 7mm smaller.

https://www.4s.com/en/ecatalog?year=1985

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[grandscapesllc]

After personal experience on several old vehicles I would definitely switch to parallel flow condenser problem with 134 in an old truck the old tube and fins don't get rid of enough Heat from the freon.

 

[jwhulon]

The Sanden A/C Compressor is much better if your converting to R134 but it runs higher pressures on the high side of the system than your original R12 system that's why some convert to parallel flow Condenser, on e of the problem that was found back in the day when everyone was doing retro fit from R12 to R134a is the oil in R12 is different and R134A ran Higher pressures which would cause lack of cooling performance at Idle or lower RPM as Auto & Truck manufactures made the change they increased the size of the Condensers to make R134A dissipate more heat due to higher pressures in the system which was causing the low Rpm performance issue, The R12 system work really really good you can use the cab for a refrigerator the compressors are still available it's the R12 that get kinda expensive but that system probably only held just over a pound of Freon if you go the R12 route just make sure you flush the system and replace any hoses that make look old in other words you definitely don't want any leaks as that will get expensive hope that helps

 

[jwhulon]

Vintage Air sells a Sanden compressor and bracket that bolts on to your engine, but it has standard (#10, #8) fittings on the back. However, on many Sandens you can buy a replacement "block' for the back that has different fittings, or you may be able to get adapters to use your old hoses. Also consider that old hoses may not be barrier hoses, which are recommended with R134a

The old A6 compressor is a true boat anchor, and the rebuilts are unreliable; however, there is a Pro6Ten compressor (https://www.oldairproducts.com/product/21-2201sh-pol-compressor) to replace it, which is apparenly a Sanden in a form factor that matches the A6.

On my truck I replaced the A6 with a Sanden and new brackets (Vintage Air), used a new parallel flow condenser (Arizona Mobile Air), Ford blue orifice (local part store), and new GM filter/drier, and had custom hoses made by a place in San Antonio (they charged me about $130). I also switched to PAG oil, and used R134a at about 75% of the R12 charge.

My suggestion for a basic upgrade: Replace the compressor, filter/drier, and orifice, flush the condenser and evaporator to get all the old oil out, and replace all the O-rings. Vacuum and recharge with PAG oil and R134a, and you will probably be happy with the results. Make sure your OEM metal fan and shroud is working well to get good condenser air flow. You might want to upgrade to an HD clutch for the fan.

Bruce

This is spot on this is exactly what i would do mainly cause if you do have any failures (Compressor or Hoses) you can go to a local parts store and get pretty much anything you need

 

[Obwonkonobe]

For inspiration I daily drive my 78 here in Phoenix, and I have no problem even in scorching heat, I rebuilt my ac with all stock parts and a 134a conversion kit and I get 40 degrees all day, some tint and insulation are used to keep it all in, but other than that I have 0 issues in the brutal az heat