Air Conditioning cooling issue

[Neil Archer]

I Just purchased a 2001 Land Yacht. It is in great shape. The only issue I appear to have is the AC system. It starts out cool and goes to warm after about 10 miles of operation. The issue appears to be the heat exchangers. There are three of them on the front of the engine. Transmission cooler, the AC heat exchanger and the engine radiator. The transmission cooler runs about 450 degrees which heats the air as it goes to the AC unit which heats the air as it goes to the radiator. Is that a standard set up for the Workhorse running gear? Has anyone moved the transmission cooler to another location? With the existing setup there is no way that the AC is ever going to work. I am looking at relocating to Transmission cooler to remove the heat source from the front of the AC unit and would appreciate any input you may have.

[HowieE]

How are you reading that transmission temperature? That seams very hot and yes if it is that hot it would influence the condenser.

I would verify the trans before anything else.

[PaulnGina]

450 degrees? Oh, my!

Agreed, I would verify the temperature first. 450 is extremely high and I think you'd be having other issues if it was really that high.

In general, here's what I like to do for any automatic transmission that will be working hard:

First, make sure all radiators are clean on the outside. Don't damage the fins, but give everything a good blast of water from the garden hose. If you can get inside the engine compartment and shoot the water from the inside out (opposite of the normal airflow), that can dislodge a lot of crud that can build up.

For the transmission cooler, I like to have it mounted somewhere by itself. Like you, I have never liked the idea of stacking separate radiators together. I have a Tru Cool Max cooler on our F250. You'd have to contact them and see if it would be OK for your application. Can't imagine it not being OK as long as you have somewhere to mount it that will catch some airflow. There are other types of coolers, including ones that are fan-assisted that you can mount anywhere you have room for it, thus not having to rely on direct airflow. I would go with the biggest (most cooling effect) cooler you can reasonably find. A cool transmission is a happy transmission! Just like anything else, the sky is the limit. However, depending on how handy you might be, this is one modification that doesn't have to be a money pit to result in good results.
http://trucool.com/products/tru-cool-max.

Use a high-quality transmission fluid. I'm sure opinions abound here as to what you should use.

For the transmission cooler and the engine radiator, of course you'd want to do a basic fluid/filter service. It would be a good idea to have a transmission shop check out your new purchase. Hopefully you know of or can find a good shop to work with.

Good luck!

[SpletKay06]

That is a standard cooling setup and well work fine once everything is in good order. Now if your transmission is hitting 450 degrees it's done and needs rebuilt immediately. More than likely it's not really running that hot though and your probably using a temp gun on the ac condenser.

If your Ac stops working after about 10 minutes there is probably a low charge or a restriction that's causing it to freeze up. Either way it well need serviced by a professional.

[HowieE]

The easy way to test if the evaporator is freezing over is does the air flow drop as the AC stops cooling. If the discharge air flow volume remains as when you started the evaporator is not frozen.

[SpletKay06]

The evaporator freezing isn't what I was referring to but that is good advice. Usually it's either an accumulator with excessive moisture in it or a plugged orifice that freeze up. Neither of which well cause any restriction to air flow in the cab.

[J. Morgan]

Does the compressor continue running when it stops cooling?


Gradiens super tenui glacie.

[PaulnGina]

When I first bought our 1995 F250 about 5 years ago, the AC didn't work well at all. Freon (or whatever is in it) charge was good, and we noticed that the AC would get nice and cold if I sprayed water on the condenser coils. Found that the fan clutch was not working like it should, so it was not drawing enough air across the coils. Replaced the fan clutch, which gave it that noticeable "whoosh" sound when you'd start the engine cold, and allowed the AC to function properly.

[Neil Archer]

Reread my post, temp should have read 250F. What I have done to date: Flushed the engine cooling system, cleaned the radiated exterior as best I could. Vacuumed the AC system, replaced the dryer, removed the AC air duct cleaned the core. Verified the position of the AC/heater selector, replaced engine fan clutch, recharged the AC system. Ran the system in place. What I found was, as the engine and transmission got to operating temp the AC high side pressure stayed constant but the low side started to rise. The higher it got the warmer the vent air got. I did not measure the vent temp, only be feel. Is there anything else I should check.

I did learn one other important thing, GM dealers have NO contact with WorkHorse. I went to several RV dealers without much success. I contacted the truck service that services my company trucks. He deals primarily with OTR trucks. He looked at the system and after listening to his discussion about cooling system. He said the arrangement was poor to say the least (his statement was much more colorful). He said the transmission cooler need to be relocated. He is working on that s we speak. Any thoughts/comments would be greatly appreciated

[Al and Missy]

IMO, even 250 is too hot for the transmission fluid longevity. A better target would be 175-200.

Al

[PaulnGina]

I don't know if you have room or not, but I have added a Flex-a-Lite 180 electric fan to our 1981 Bronco's Radiator/AC condenser. It is wired to come on when the AC compressor comes on, and/or it has an adjustable thermostat that you can set to have the fan come on at a wide range of temperatures.
The Bronco AC worked typically in hot weather: sitting in traffic, the temp would go up because the belt-driven fan could not pull enough air across the radiator/AC condenser. This awesome fan fixed that. I recommend it highly.
https://www.amazon.com/Flex-lite-180.../dp/B000CNHFNA

[SpletKay06]

I hate to say it but your compressor may be going out if your high side is holding good but your low side is rising out of range.

[HowieE]

Can you give us gauge readings for the low side?

Another check would be to feel the suction line just before it goes into the compressor. If it is hot the valves in the compressor are leaking back to the suction line.

[pago cruiser]

We have been/are still struggling with the dash ac in our 96LY as well. Same (I believe) setup. But you made no mention of the shared condenser.

We replaced most components (compressor, hoses, receiver/drier, TXV), except the condenser. The shop we used does RV Reefer work for most of the major RV places here in Tucson. Both techs (it was a long day...) indicated that the arrangement of the shared condenser (reefer on top, engine oil on bottom) resulted in the smallest functional condenser size for any 30+'Motorhome they had seen. Both systems in one aluminum component also compromised the performance of each system.

Which was the reason they gave for the poor performance of our system, even after getting it dialed in. In 100F weather we could barely make a 20F differential.

I have since found some aftermarket dedicate condensers that will fit the opening, AND basically increase the surface are (and the heat rejection capability) by about 30%. Obviously, this will also require a separate engine oil cooler.

Once you get your "10 minute" problem resolved, may want to look at this as well.

[dznf0g]

Originally Posted by HowieE

How are you reading that transmission temperature? That seams very hot and yes if it is that hot it would influence the condenser.

I would verify the trans before anything else.

Not really. The normally discussed "normal" trans temps are measured at the sump....after cooling and before being drawn into the trans innerds for lube and cooling. The general path for this "normal" cool (190* - 200*ish) is from sump to pump. from there some is split off for lube, cooling and hydraulic application of trans innerds. The lion's share goes to the torque converter. When the TC is not locked, there is a tremendous amount of turbulence and friction created in the fluid. The fluid leaves the TC and goes to the cooler. It is very hot at that point. That is normal. However, is 250* normal for that particular trans? The only spec you are likely to find is for sump temps. If they are abnormally high then 250* is too hot. If sump temps are normal, then 450* is fine.