What to do with my old A/C thread #10425

[L31MaxExpress]

I see many 'experts' on this forum that really crack me up. Most don't even really use their gmt400. Bolting them together and taking pictures of every little ******* step isn't actually the same as using it on the road.

Example - you'd have to drive a gmt400 in the same exact setting as the f550 and then compare...

I do that often with my f150, a new duramax, and have used a newer 6.2 F250 too. The results are - the airflow in the old gmt400's isn't very good. You can really improve things by insulating etc, but then the windows start to fog, cause the airflow just wasn't designed to work very well. It still works ok. You won't sweat to death.

All vehicles have good and bad points - just the way it is. I love my gmt400. Not enough to stick my head in the sand though.

Umm I daily drove both my Van and my Tahoe. 30-40 mile commutes each way every day. I drove the van or Tahoe 3 or 4 days a week and my Titan and my M56S 2-3 days a week. I had the Tahoe up and running and the van was down at the time. I had the 2012 Titan and the Van at the same time and drove them back to back. I drove the Tahoe and the M56S back to back the same way while I rebuilt the van as a 1-ton with the 383. Tahoe is about to get the 8.1L dumped back into it. Years ago I also swapped back and forth between my 1983 G20 van and my 2006 Ram when I had the Ram. In the heat of summer, I usually drove the G20 van every day. Sit in bumper to bumper traffic on a 108F day where the air above the road is 120-130°F. That will test the best ac systems. The absolute worst AC was my 2006 Ram closely followed by my M56S when it had the stock engine tuning. Nissan/Infiniti chose not to command more than 60% duty cycle on the electric fans under 20 mph, which resulted in poor cooling when the vehicle was stopped. The absolute BEST AC I have ever had was in a truck that the vents did not blow well in. However the system would freeze you out because the air would blow so cold and the truck was white. It was a regular cab 1994 Dodge 2500 V10 and the condenser on that unit rivaled the size of one on an 18-wheeler, massive and it had a large engine driven fan. I have been on 1,000 mile or more long trips in every vehicle I have ever owned. The most comfortable vehicle to drive on long trips was my 1983 G20 van hands down. AC would freeze you out, it got good mileage for what it was, the engine was quiet with 3.08 gears and the 700r4 and later 4L60E, and with the old over assisted GM power steering system you could guide it down the road with a single finger while it floated down the road. With 200K on the stock 305 and 700r4, I never worried about it. Even took it on a 3,000 mile road trip towing a small pop up camper trailer. I kept a few quarts of oil and a simple tool box with me. On one trip I had to change valve cover gaskets at a KOA I spent the night at. On a different trip I had to replace a smog pump that seized up and took out the alternator belt. When I realized the alternator was not charging, I shut off everything and I made it 100 miles without a belt on the alternator to the nearest town. Saving grace there was it was day light and the only thing the battery was running was the HEI.

 

[someotherguy]

I see many 'experts' on this forum that really crack me up. Most don't even really use their gmt400. Bolting them together and taking pictures of every little ******* step isn't actually the same as using it on the road.

Example - you'd have to drive a gmt400 in the same exact setting as the f550 and then compare...

I do that often with my f150, a new duramax, and have used a newer 6.2 F250 too. The results are - the airflow in the old gmt400's isn't very good. You can really improve things by insulating etc, but then the windows start to fog, cause the airflow just wasn't designed to work very well. It still works ok. You won't sweat to death.

All vehicles have good and bad points - just the way it is. I love my gmt400. Not enough to stick my head in the sand though.

Can we please move this stupid argument to its own thread? Because now you're actually talking trash about people on here and making big assumptions about how everyone uses their vehicles. Do you really think others don't actually drive/work their trucks on a regular basis? I've had half a dozen gmt400's that were daily drivers/work trucks for 2 decades. Please get off your high horse. A/C performance can be measured but most of what we're discussing here is purely subjective.

Richard

 

[Carlaisle]

If I was doing the work, I'd be tempted to nab a clutch from the junkyard and see what happens. If no joy, then go all new. I would anticipate some seized fittings. I ran into some on mine with serious separation anxiety. I'm not sure on your year, but on the later model years you need metric line wrenches. For your future trouble shooting convenience, I had to go through several bad out of the box pressure switches before getting one that worked reliably.

 

[someotherguy]

If I was doing the work, I'd be tempted to nab a clutch from the junkyard and see what happens. If no joy, then go all new. I would anticipate some seized fittings. I ran into some on mine with serious separation anxiety. I'm not sure on your year, but on the later model years you need metric line wrenches. For your future trouble shooting convenience, I had to go through several bad out of the box pressure switches before getting one that worked reliably.

My initial plan once I found the broken clutch connector was to boneyard a clutch, but judging from the overall condition of this junk wagon, I'm not terribly sure I want to invest time and effort into a compressor that is questionable. I'm kinda thinking if I could pick enough of the broken plastic away to solder temporary wires to the clutch just to test the compressor, and if it's good, then I could bother with replacing the clutch.

One thing this truck has taught me is that every time I think something is gonna be a small project or I'll get by with some minimal means of dealing with an issue, it turns into a huge job. It's been like this with practically every step. Even the muffler shop guys battled it today trying to get the old tailpipe remnants out of the muffler outlets, and only one side was welded - other side was simply clamped, but seized in there.

Richard

 

[L31MaxExpress]

Richard,

Aside from the fact that some want to hate because my currently running GMT400 has a van body and my Tahoe has had the 8.1L out of it for a couple of years because it burned a valve, the machine shop took a year on the heads and I have had life in the way of putting it back together, here is the Four Seasons information on the Scroll. They claim it has a 106cc pumping capacity and that their piston R4 has a 188cc pumping capacity. The small difference in pulley diameter does not come close to bridging the difference. Frankly, I believe Four Seasons, they are a Lewisville, TX based company and my half sisters mother worked for them for years in their sales office. They have respectful people working for them and all the information I have read from them is accurate. Solid and reliable in nearly everything I have purchased from them. Years ago when I was in trade school, I toured one of their facilities in Grand Prarie, TX that built evaporator cores, AC hoses, and remanufactured compressors. Very clean and neat operation at that time and the products were bench tested.

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[L31MaxExpress]

The fan clutch being engaged at 75 mph alone should tell people that I am using my Express van bodied GMT400 hard towing my 6K travel trailer. It has the same suspension, similar frame, same driveline, same AC system and so on, so I have no problem calling it GMT400 based. So much for not using a garage ornament that I have posted tons of build pictures and information on. I know some dream of having the driveline and additions I have added to the van that has been in the family since it was a year old. No sweat off my brow though. Some have actually reported the fact that I suggest against converting to electric fans based off real world experience as well. Is what it is to be honest. It works hard for me and I still enjoy driving it better than most vehicles I have owned. I have put nearly 8K miles on it in the last year since it has been back together as a 1-ton with a 383 and nearly half of those have been with a heavy trailer of some kind. 8K miles, with heavy towing on a ~500 hp engine I built from the ground up mind you and I am the retard. Same engine I fixed in chassis after head bolts failed too mind you.

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[L31MaxExpress]

Also FYI, I am fighting an inadequate compressor at the moment too. The Sanden 4261 has less capacity than the GM HT6 or Valeo DKS17D and it is something I discovered replacing a malfunctioning rear expansion valve. Inadequate compressor capacity will cause cooling issues in our Texas heat and most noticeable at idle and around town. I will admit I should have done more research before choosing the Sanden 4261 SD7H15 and talking it up, but I am not responsible for a company marketing an inadequate product for the application, similar to the R4 Scroll. I had a R4 scroll too because of the hype and it sucked.