2nd Gen Non-Engine/Transmission AirCon Performance

[JohnMcIntyre]

Just a couple of quick questions... ... my early model 2001, 1 ton has the original AirCon R-134a type gas. Just recently I noticed that the aircon cooling effect, even at the maximum possible setting, is not as efficient as it used to be especially with daily highs in the upper 90s, considered unseasonably warm for this part of the world!!



With almost 3 years and 50,000 miles on the clock, when does the AirCon system need bleeding and refilling to maintain optimum performance and how much R-134a gas would it require?



Cheers

 

[BarryG]

Would also love to know the answer to this as my 01. 5 definitely seems to have trouble keeping up this year when it is over 90 which is most of the time here in the summer. The previous summers it has had no problem keeping me cool.

 

[krs]

It's not much gas and there should be a label under your hood(s) indicating the fill amount. I don't remember offhand, but 1. 8 lbs. seems familiar for some reason.



One can should fix you up if there are no leaks in the system.

 

[TPCDrafting]

I'm not an A/C guy but the one time mine worked best was when we accidentally pulled a line while putting the truck back together on another project. My mechanic and fellow TDR member had the tools at his work to put a vacuum on the whole system, then refill with coolant. The a/c worked great! Albertson's called they wanted to hang meat in my truck! This past summer I had some other work done on the truck by the dealer and they had to pull the front end off which meant they must have needed to refill my a/c and it works good still but nothing like when I had it vacuumed and refilled. If you can get your hands on a vacuum setup which had all the hoses and connectors to do it right, you'll be set. That might be something you'd want for your wrench day Barry.

 

[BarryG]

TPC:

Great idea. I will have to check into that vacumn setup. When it is not roasting out it works ok but 90-95+ and it cant keep up and it is not even close to keeping up air is barely cool. Used to be driving in high heat on the freeway I could only keep the fan on low and at times cycle it off and on because it got to cold in the cab. Earlier this year I put 180 deg thermostat in could that have anything to do with it?

 

[Jetson]

The A/C system can seep a little over time. It's probably just a can low on 134. You need to put a guage on it to be sure, but adding a can will probably bring back to original performance.

 

[Fast 1]

Right on Jetson, I would and have before just added one can and it did the trick. If it needs more than that I would get it checked out.

 

[krs]

"Albertson's called they wanted to hang meat in my truck!"

 

[mcoleman]

Try hanging a manifold gage on and checking your pressures. If they are normal I would suggest an electric fan in front of the condensor. And make sure your fan clutch is working correctly. Your asking a lot of the engine driven fan to pull air through the condensor, intercooler and then the radiator. Mine was shutting down while in town with temps in the high 90s. Pressure was fine but hardly no airflow through radiator to cool the condensor when idling in traffic was causing the ac to warm up while sitting and driving slowly. Out on the highway everything was great. It would get so hot sitting still that the high pressure switch would kill the compressor. Placed a box fan in front of it and it ran fine. That let us know that I either need a new fan clutch or an electric fan for the ac condensor. My truck doesn't run warm but I still haven't ruled out needing a new clutch either. Pulling a vacuum on your system is done in order to boil the water and moisture out of the system as well as checking for leaks. I usually let a system set for 30 or 40 minutes with at least 28 inches of vacuum to make sure everything is good.

 

[JohnMcIntyre]

R-134a refill [update]

I just checked chapter 24 of the 2000 model year service manual which covers the AirCon system. After bleeding the system and performing a vacuum test, the refrigerent required is stated as 32 fluid ounces (0. 907kg)



When I checked chapter 24 of the 2001 model year service manual [update]which also covers the AirCon system, the refrigerent required is stated as 30 fluid ounces. (0. 85Kg)



When I popped the hood there's a sticker on the front LHS near to the AC radiator which says 0. 907 kg (aka 2lbs). That's the value I went for plus an additional 0. 150kg that was in the system paperwork. (Not forgetting to top up the oil with another fluid ounce which always gets sucked out when the vacuum test is performed!)



I guess it's a typo (or undocumented feature) in one of these service manuals or did the AirCon system requirements change between the 2000 and early 2001 model years?



It would be nice if DC could sustain some consistency across the board here



JMc

 

[LR Smith]

Go to Walmart and get the Interdynamics R134 top off kit. $19. 95 includes a removable pressure gauge for the low side that indicates the proper charge amount and an R134 /oil charge/seal revitalization agent all in one. The gauge is also removable and can be used without the recharge. Just added a half a can of this to my 2000 model with 175K. The AC performance has been degrading over the last 2 summers, and the gauge indicated a low charge. After adding R134 to get proper low pressure reading, cools MUCH MUCH better.

Lain

 

[BSnyder]

AC

My 99 just got warm on me last month I went to Advance Auto Parts and they sold me a 134 kit with everything in it for about $20. 00. The kit has a gauge on it and the can contains 134 coolant, oil, rubber seal revitalizer, tubing sealer, all in the proper premeasured amounts and good directions. Good-Luck! My truck cools like a freezer now!! Brad

 

[Lsfarm]

Over time

Another item to check is how clean the condenser, intercooler and radiator are. The engine driven fan is capable of pulling enough air over the condenser at idle if the radiator and intercooler are clean. But with time, the fins get clogged with dirt and dead bugs.

One major culprit is the crankcase puke bottle on the front of the engine. It causes a coating of oil on the front of our engines, but also on the engine side of the radiator.

You may ask, how can this happen when the fan is pulling air through the radiator? How does the oil mist travel 'upwind' ? Have you ever watched a movie of a helicopter landing on a dirty dusty surface, and seen the air recirculate around the rotor blade tips?? The same thing happens with a radiator fan, the plastic fan duct eliminates a lot of the recirulation, but not all.

The oil mist from the puke bottle coats the engine side of the radiator with a layer of oil, then road dust and dirt stick to it, and then the radiator effectiveness is reduced. I have seen this on several customers' trucks.



So check out the radiator fins to see if they are plugged, this is a fairly easy, no cash fix. Good luck!



Greg L. The Noise Nazi

 

[jphunter55]

A/C

The A/C sticker under the hood on my 98 3500 says 2. 00 lbs. of 134a.