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4x4Poet · 03-21-2010, 01:50 AM

I'm also dissapointed in aftermarket A/C systems for our trucks that don't use cowl fresh air.

But I wonder if a little simple duct work would make either cowl or pass side vent fresh air flow through the evaporator. For the side vent, a drawback might be less leg room to accomodate the vent ducting. A fresh air/recirc flapper would be a greater challenge for the side vent.

Anyway BLT-, Since you have the factory system, to use R134 you just need to go throught the conversion process above to use R134. To use a Sanden compressor, the R134 conversion hoses must have correctly routed and configured compressor hose fittings since any retro-fit R134 hoses configured for the OEM piston compressor will have the wrong fittings and metal line bends for a Sanden. Hose lengths required can also differ.

Most A/C hose makers can make R134 hoses for Chevy trucks to SBC/BBCs. They'll need to know the truck, engine, pulley system, compressor location, etc. before making up a set. Classic Auto Air, Vintage Air, etc. can make up a set if local sources can't.

I prefer R12 for its superior cooling ability, but, as stated above, R134 can easily handle a pickup cab. I use R134 barrier lined hoses even for refurbishing an R12 system since they are superior for stopping leaks and the cost is comparable to non-barrier R12 hoses.

03-21-2010, 01:50 AM	#23
4x4Poet Registered User Join Date: Nov 2004 Location: "Under Montana skies." Posts: 1,836	I'm also dissapointed in aftermarket A/C systems for our trucks that don't use cowl fresh air. But I wonder if a little simple duct work would make either cowl or pass side vent fresh air flow through the evaporator. For the side vent, a drawback might be less leg room to accomodate the vent ducting. A fresh air/recirc flapper would be a greater challenge for the side vent. Anyway BLT-, Since you have the factory system, to use R134 you just need to go throught the conversion process above to use R134. To use a Sanden compressor, the R134 conversion hoses must have correctly routed and configured compressor hose fittings since any retro-fit R134 hoses configured for the OEM piston compressor will have the wrong fittings and metal line bends for a Sanden. Hose lengths required can also differ. Most A/C hose makers can make R134 hoses for Chevy trucks to SBC/BBCs. They'll need to know the truck, engine, pulley system, compressor location, etc. before making up a set. Classic Auto Air, Vintage Air, etc. can make up a set if local sources can't. I prefer R12 for its superior cooling ability, but, as stated above, R134 can easily handle a pickup cab. I use R134 barrier lined hoses even for refurbishing an R12 system since they are superior for stopping leaks and the cost is comparable to non-barrier R12 hoses. __________________ '71 GMC K20 Suburban, '71 GMC K10 Suburban, '72 Chevy C10 CST Suburban, '72 Chevy K20 clunker pickup. Last edited by 4x4Poet; 03-21-2010 at 02:04 AM.