Keeping interior cool

[L31MaxExpress]

I used a pec valve on my super duty, worked great.

Have you ever ran a blue orface tube?

Yes as well as a Red and Orange. 0.062 Red has consistently worked the best in GMs for me. Currently have a variable in my van and so far it is working great.

 

[Cadillac Bob]

This should help some if you haven’t already done this but there’s a about 3-4” hole in firewall on passenger side if that’s partially open you will take on heat/cold depending time of year. Cut a oversized circle outta foam that’s pliable an once you find you may have to put a slit/hole in it for like mine had a line coming through but cut it tight as to compression fit an keep foam in place! That should help out especially passenger side keep cool but you may have a boot still mine was pretty open an did it due to cold but help keep an even temp up front I know that’s not particularly making things colder but if you air better maintains temp then it will be cooler since less heat loss!! I’m an union mechanical insulator so I know a thing or 2 on keeping temps!! Lol an also put ac on part of your body that arteries are at that will cool your blood some we roll with ac on floor to cool your ankle that a main artery runs but we also roll with windows down and backseat ac on too to keep kids kool but not too cool as we live in Michigan and summertime is a quick time of year so it’s best to fully enjoy it vs always living in conditioned air space!

 

[454cid]

Even the ones GM put on do not fully close. I put a manual ball valve on mine. It is closed about 9 months out of the year here.

If your ac is not working well it is not the era of truck. I have been in a family of this generation of trucks, suvs and vans since they were new. My uncle had a 97 ECSB and my aunt had a 98 Yukon that they had since they were new back in the day, long since sold them. The 97 Express has been around since 98. My brother and I have had no less than 7 Tahoes, Yukons, Suburbans and Trucks. The 99 Suburban and 99 Tahoe we kept for several years would both freeze you out of them. If the ac is not cold it most likely has a leak or airflow across the condenser issue. If the ac is blowing weak the evaporator is clogged with crap or the blower motor is weak. The foam seals at the duct work also degrade over time and leak the air out behind the dash. Wrap the joints in the ducts with aluminum tape. My van and Tahoe will both blow your hat off with cold air.

My AC has never worked well. I figure it's a factory defect. Back when it still worked, it struggled to keep up with the sun coming in the windows, driving down the highway. It's a regular cab, so it should not be hard to cool. I had the dealer check it out under warranty, and of course they said it was fine. I think the compressor started going bad at some point, as eventually you could really feel it kicking in and out... and I feel like a AC compressor shouldn't be dragging down a big block.

I did sort of have plans to completely rebuild the AC system, but at this point I don't think it's worth it anymore. I don't drive it enough.

I miss R12. I remember GM B-bodies from the 80's.... you could practically keep milk in them

 

[Donald Mitchell]

My AC has never worked well. I figure it's a factory defect. Back when it still worked, it struggled to keep up with the sun coming in the windows, driving down the highway. It's a regular cab, so it should not be hard to cool. I had the dealer check it out under warranty, and of course they said it was fine. I think the compressor started going bad at some point, as eventually you could really feel it kicking in and out... and I feel like a AC compressor shouldn't be dragging down a big block.

I did sort of have plans to completely rebuild the AC system, but at this point I don't think it's worth it anymore. I don't drive it enough.

I miss R12. I remember GM B-bodies from the 80's.... you could practically keep milk in them Mine worked a couple of years after I got it and I did put a compressor on it and change to r134. When it quit working i found a spot on the condenser where something had hit it and was leaking. It was just a work truck back then so I never fixed it. Now its my retirement toy and I want the A/C. Never know when I may need a haircut or something important like that.

 

[95burban]

When I tinted my whole front windshield it really kept things cool.

 

[east302]

When I tinted my whole front windshield it really kept things cool.

What did you use - clear film?

 

[Carlaisle]

My AC has never worked well. I figure it's a factory defect. Back when it still worked, it struggled to keep up with the sun coming in the windows, driving down the highway. It's a regular cab, so it should not be hard to cool. I had the dealer check it out under warranty, and of course they said it was fine. I think the compressor started going bad at some point, as eventually you could really feel it kicking in and out... and I feel like a AC compressor shouldn't be dragging down a big block.

I did sort of have plans to completely rebuild the AC system, but at this point I don't think it's worth it anymore. I don't drive it enough.

I miss R12. I remember GM B-bodies from the 80's.... you could practically keep milk in them

Ah, the good ol' A6. I think that was the largest displacement production auto AC compressor anyone ever used. It's ability to turn the interior of a sheet metal and single pane glass greenhouse on wheels into a refrigerator was spectacular. I've seen some documents that said it delivered over a ton of cooling at idle. I'm inclined to believe this because you could hear and feel the load it placed on the engine. I seem to remember that running it noticeably reducing fuel economy.

 

[L31MaxExpress]

Ah, the good ol' A6. I think that was the largest displacement production auto AC compressor anyone ever used. It's ability to turn the interior of a sheet metal and single pane glass greenhouse on wheels into a refrigerator was spectacular. I've seen some documents that said it delivered over a ton of cooling at idle. I'm inclined to believe this because you could hear and feel the load it placed on the engine. I seem to remember that running it noticeably reducing fuel economy.

80s would have been the R4 for most GMs. My 83 G20 had an A6 and it would blow ice cubes on R12 on both ends. The van being the shape of a brick really did not notice a fuel mileage change.

Late 60s and early 70s is what I think of when someone mentions good ac in a GM. They used an expansion valve with a STV or POA system and that old A6 ran continuously while the evaporator was throttled at a pressure just above freezing.

Where GM messed up is going to the cycling clutch orifice tube systems, especially after the change to R134a. The imports with the H block TXV systems wipe the floor with an orifice tube in idle/low speed ac performance.

The old A6 kicks out 27,000 btus at 2,000 rpm and 42,000 at 4,000 rpm. By comparison the SD7H15 Sanden on my Express van is 10,000 btu @ 1,000, 18,000 @2,000, 23,000 @ 3,000 and finally gets to 27,000 @ 4,000 rpm.

 

[95burban]

What did you use - clear film?

I had 35% on the front. it really helped with night driving too, it cut down the glare from the bright headlights from on coming vehicles. Rest of the truck had 5% over factory smoked glass. In the middle of Texas summer the a/c would stay on low or med.

 

[HotrodZ06]

One possibility in a truck would be to use a Tahoe/ suburban with rear air condenser it's a little thicker to provide extra heat dissipation for the rear air. In a regular cab or extended cab it might help marginally.