So the old compressor had a leak. I changed the compressor and dryer. Old dryer had no oil in it. Old compressor had 1oz. The system calls for 4.5oz so I put 3.5 in the compressor and 1 in the dryer. Vacuumed great. Added in 2.25lbs of r134a. Hood is off. Low pressure is 45 and high was 400 to 450!. Air is cold but I dont like it that high. Did I add to much oil?
Help! Question on kubota m9000 a/c system!
- Thread starter Farmerbrown87
- Start date
the pressures will likely come down some when you put the hood back on. The air flowing across the cores is disrupted somewhat when the hood is off. Try it and see what happens. I've run into it before although not on an M9000; rather M9540 I think it was.
dvcochran
Active member
Equipment
Kubota M9000, New Holland TN90, Deere 2640, Vermeer 504N, Vermeer 504SI, more
Putting the hood back on should direct the air better, especially since there is about an inch gap between the radiator and condenser. I have tried blocking this gap but couldn't tell much difference.
Were these pressures when everything was still cool? That sounds like too much oil added unless the system was clean and bone dry. Are you certain the compressor did not come full of oil (most do)? How did you handle the rest of the system? Did you blow the condenser, evaporator, and lines out individually with nitrogen? If not, a good bit of oil would have remained in the system and little to no additional oil (beyond the 2 or so ounces in the compressor would be necessary. If you used standard compressed air, you introduced moisture (as me how I know). What about the TXV?
Since the high side is pretty high, I would suspect solubles in the system or a blockage at the TXV (could be one and the same).
The M9000 is a great utility tractor but the A/C system is just bad. The condenser (and evaporator to a degree are very small and hard to keep clean. Unless spotless, you will see high pressures and reduced cooling. I clean mine with coil cleaner, & mild water and air pressure. The condenser is the 'new style' which is just hard to get and keep really clean. With the evaporator overhead, adding generous insulation under the roof helps.
The largest aftermarket cooling fan I could fit on the condenser was some of the best money I ever spent on my M9.
Hi! Thanks for the Info. I didn't clean the system. Definitely didn't change the expansion valve but I might. I'm guessing most the oil leaked out since the old dryer was bone dry and only an ounce was in the compressor.
dvcochran
Active member
Equipment
Kubota M9000, New Holland TN90, Deere 2640, Vermeer 504N, Vermeer 504SI, more
I would expect the dryer to be pretty 'dry'. Just a film maybe since the desiccant should catch the moisture. Excess oil would cause a soluable blockage.
4 or 4.5 ounces in a completely new system sounds about right, 2 to 2.5 ounces setting in the compressor. But not added to an existing system the was not thoroughly flushed.
If I were you, since it would not cost anything, I would try the hood first. If that does not help, I would buy a TXV (pretty cheap), pull the system back down and open things up, at least at the condenser, and blow them out. With the dryer and TXV off you can get a pretty thorough flush (but do Not use flush). If you wish, drain the compressor and add 2 ounces again. Add no more than 1-1.5 ounces of oil to the system, pull the vacuum again and recharge. Don't forget to clean the condenser really, really good. Things have to be 'near perfect' for my M9 to work 'pretty good' and I never let it idle below 1,100-1,200 rpms.
It has nothing to do with your pressure issue but make certain the heater valve is completely closed by feeling both lines when good and hot.
My guess is that you put too much oil in the system. Oil can stay in the evap as well as the condenser.
Should have just added 1 oz, since that was the only oil removed.
The oil forms an insulating later between the refrigerant and the heat exchanger tubes. That would explain the elevated high side pressures.