AC Issue M9540

[AllDodge]

Its getting cold so AC not needed, but tried a changes and cleaning and its still not doing good.

At idle
Low is 50 psi
High is 250 psi

The above pressure was done on a 85+ degree day and looking at R134a should be about the correct pressures.

When I increase the rpms low goes down and high goes up but not much. So do I need more or less freon, or something else may be happening?

 

[Tx Jim]

Is radiator/condenser very,very clean? How long since cab filters were cleaned/changed?

 

[AllDodge]

I cleaned all the filters, even removed the seat to verify the damper is working. The radiator and condenser are very clean. Have not go into to verify the evaporator is clean, looks to be to hard to get at

Wondering if the pressures are right

 

[eserv]

I cleaned all the filters, even removed the seat to verify the damper is working. The radiator and condenser are very clean. Have not go into to verify the evaporator is clean, looks to be to hard to get at

Wondering if the pressures are right

Pressures look about right for that temperature, Di you have good airflow through the cab vents?

 

[AllDodge]

Air feels decent, but will say my truck and car push more air, but also when I have it on high you can really hear the fan also, not so much with the tractor.

If it is a bit clogged, I would think it would be cold just not moving enough air. The air is cool but not cold, and once the sun starts coming in good, it starts getting warm in the cab

Guess I can hook the gauges up on the backhoe (which I have before) to verify that the low side drops as rpms go up. Just never much paid attention if it would do that before

 

[wgator]

If you don't already have it, , HERE'S LINK TO WSM AC PRESSURE CHECK
By this, see CONDITION at top of page, from what your first post said, if you tested at 1500 RPM, lookin at gauge readings in WSM for Normal Operating, seems like you have too much refrigerant in system.

 

[AllDodge]

Thanks for the link, Will need to double check, but do think I'm seeing about 30 on the low (21 to 28 psi), but might be slightly high (185 to 242 psi) at 1500

May also have an issue with someone not purging hoses and let some air in

 

[D2Cat]

When you removed the seat working on the dampers, did you check the blower motor? It needs to be clean and not dragging. When that motor needs to be replaced it's a bit over $500, and there is no workaround that I can imagine!

 

[lugbolt]

Your pressure readings are inconclusive.

Remove the top of the heater box, just has a few screws. Set it to the side. Then remove the evaporator. The hoses are flexible but you still want to be careful with it. You can actually set it to the outside of the door and wash it out. Get you some good a/c evaporator coil cleaner, it works pretty good for getting most of the dirt out of the evap core. Let it dry out, then reinstall it. It's not really that hard. I do them at work, full a/c system check/cleaning on those tractors in the spring for about $250, including all the data to verify that things are working as designed. Ambients, evap temp, doors open vs closed, condenser temp, humidity, and a bunch of other things. I do it that way for good reason. If it were to come back in the summer for a/c not working, there was no question that it worked "last time it was in" (if they had it in for servicing), thus we KNOW to look around for issues.

I had an owner ask me to "improve" his a/c on a 8540 last season. One of the things that we did was tint the windows with the good 3M tint (well, we paid another shop to do it), AND we put a self-adhesive duct insulation on the bottom of the cab roof everywhere we could. Between the two, the windows will fog up in high humidity (normal for here) days in the hottest part of the summer if you don't turn the a/c temp up a little. Customer says he has seen 65 degrees in the cab but couldn't stand it. The pressures will change quite a bit based on the temp of the air inside the cab. On his, started out around 50 (about 235 on the high side), but as the temp inside the cab cooled, it would get down around 26 psi and start cycling the compressor like it's supposed to do.

 

[AllDodge]

full a/c system check/cleaning on those tractors in the spring for about $250, including all the data to verify that things are working as designed.

Didn't know it would come out that easy, didn't even try. Will have to look closer next time. Its 40 degrees this AM

Will check with dealer, if charges the same, might just take it to him in early spring

Thanks

 

[AllDodge]

Finally pulled the evaporator out and it does work better now. Pulled more out then I need to with the floor plate and side Lock Dif plate, but go it done.

Remove seat, then have to unfasten both plastic covers to get at 2 bolts. There is one bolt on each side. Then remove exterior intake duct by removing two 10mm nuts. Then the plate can be removed. Screws covering Evap and out it comes

It was pretty clogged

Also best to remove all the bolts holding the entire unit in. The lines are flexible, but the unit needs to be moved toward the rear to get the Evap out

 

[lugbolt]

yes that is exactly how I do it too. There's one screw in the box that can be a bear, but it's not terrible.

Get it cleaned out good and reassemble.

One thing that I did a little of while doing kubota work was to remove the top of the cab. A few screws around the perimeter (just take out the long screws-and be aware that the 3 or 4 in the front are a different length than the others). Leave the short screws in. Then just lift the top off. I'm pretty tall so I did it by myself without issue, but if you're a little shorter it might be worthwhile to ask for a little help (it's not heavy, just kinda bulky). Clean the bottom of the top real well and then apply some self-stick heat reflective stuff. This helps two things--(1) reduces some of the noise and (2) helps the a/c work a little better. Ceramic tinted windows help too-quite a bit I might add. But I also understand that some don't really like tint. I'm on the fence there.

Your a/c low side pressure will drop with temp. So as the cabin interior cools off, your psi will also drop. That's something that a lot of a/c "mechanics" don't think about. You don't turn your a/c on in a 90 degree cab and expect to see 35 psi. You expect to see 22-35 psi after the temp inside the cab is cooled down which might take a while if the machine has been sitting out in the hot sun all day.

 

[AllDodge]

Good to know
I like tint, have had it installed on all cars and trucks, but have yet to do the tractor. Should do it, but getting around to loading up and hauling is my issue. Have the equipment just need the cattle prod on me to get moving