4240 AC noise

vrickster

Member
A minute or so after I turn on the AC, the compressor start giving out a loud high pitch noise. It does not seem to be belt slip. It quits the moment I turn the AC off. This is the 3rd time this has happened in as many years. The shop I take it too replaces the compressor and all is well until next season. I have a hard time believing the rebuilt compressors they use would go out so quickly, I am beginning to wonder if the shop is doing something wrong. Any thoughts on the cause?
 
are you blowing out your filters and evaporator and condensing coils. I just replaced a compressor on one of my 4230's and one of my 4430's, Did it myself as I have all the tools to vacuum it down and recharge. The 4430 was not cooling well at all, checked the evaporator coil and it was about half plugged up so it would get very little air flow. This could cause excess wear on a compressor and cause it to fail, also you have to change your dryer and your supposed to flush the system.
 
The sound you hear is the compressor clutch slipping.


Your shop needs to find out why. It is caused by low voltage to the clutch, poor air flow through the condenser, or both.

Low voltage:
This is the longest circuit on this tractor. Any loose, dirty, corroded connections will result in reduced voltage, less magnet strength, and reduced "holding power" at the clutch. If you don't have 12 volts at the compressor [b:654c4848f0]with the alternator running,[/b:654c4848f0] this needs fixed.

Poor air flow:
This is the real AC killer on older Deere tractors. Several times I've been called out in the last couple of weeks for complaints just like yours. I'll ask the operator if the condenser and radiator are clean and they'll reply "oh, yeah" or "we just cleaned it". When I get there, the discharge pressure is 100 to 150 psi too high because the radiator is usually plugged. A customer will pull back the side screen, wipe the fins, and think it's clean. If there has been any coolant, fuel, or hydraulic oil getting into this area, it really causes the dirt and chaff to become lodged in the cores. The only way you are going to clean it out after things have deteriorated this far is to remove the condenser and radiator for hot pressure washing. {more fun with a loader installed}

When reinstalling the radiator, remember to put in new foam rubber around the hydraulic pump. {I'll about guarantee yours is all missing} This foam's sole purpose is to keep chaff from being drawn up into the coolers. My point? No one regularly cleans their equipment anymore. Waiting until the engine or the AC "runs warm" to clean it just doesn't cut it. By then the compressor has already been heated and stressed from operating at 380+ psi instead of a more sustainable 250 psi.

Think about it. Pressure is load. Your car will last 150,000 miles at 60 mph. At 120 mph, will it last 1500 miles? I doubt it.
 
Besides all the other suggestions, the belt must be TIGHT. TIGHTER than you'd think.

Also, what is the condition of the V-belt groove in the crankshaft pulley... they DO wear, and cause the belt to slip.
 
I do have a FEL so it is tuff to clean the radiator/condensor. As I push the condensor left and right to clean, the FEL has always been in the way so I can only expose 1/4 of the fins on each side. I tell you, I have had this tractor for over 10 years. Well, last week I figured out that with the FEL raised to its highest level, I could expose 1/2 of the fins on each side. I cleaned and cleaned with water and compressed air for about an hour. You should have seen all the crud left on the concrete apron.
After doing all this the noise problem did not go away. The tractor is now at the local shop for a new compressor, they say it needs it. I hope this takes care of it but I don't have much confidence.
 
New and rebuilt A6 AC compressors haven't been standing up well for last few years with R134A. There are update conversion kits out there sold by lots of aftermarket parts places with newer style compressors that are holding up better like 3 to 5 years instead of months or a year compared to others. Putting on a A6 anymore is just kind of wasting money better spent on updating it.
 
Sorry for the slow reply.

[i:654c4848f0]"Is there anything I can check after the local shop is done with the repairs? [/i:654c4848f0]"

Possibly.
In general, I don't think the average tractor owner has any business working on his own AC internals...Heck, from what I've seen, a lot of guys who are paid to work on them need to turn in their tools until their 500 hour failure rates are well under 50%. You seem to be motivated into solving this problem, so spending a little time with you may be productive.

I wouldn't buy [b:654c4848f0]any[/b:654c4848f0] parts until the system is thoroughly cleaned inside [b:654c4848f0]and[/b:654c4848f0] out. But since your 4240 is already in the shop, Here's what I would do when you get your tractor back, assuming you have a better than average amount of "farmer skills". {That's a good thing to have, not a put-down}

1st- I would remove the loader and the loader frames to tighten up the tractor side frame bolts. My crystal ball says this hasn't been done in years. If left loose, this causes mega $$$ of expense in your immediate future.

Next- With the loader out of the way, You really can direct your attention to the problem area,- The condenser, the radiator, and everything around it.

Slide the condenser halfway out to the cab door side of the tractor. Get it wet. Put on some goggles. Hold a clean white paper towel to the front side and apply a 150 psi air nozzle from the rear. The towel should only have two things on it - Water and maybe some black paint chips. Does it have any dirt on it? Then it ain't even close to being clean,- yet. Looking through it, You can see daylight through most of the fins, so it [b:654c4848f0]must [/b:654c4848f0] be clean, right? Not so. Air needs to be free to "swirl" 360 degrees around [b:654c4848f0]each [/b:654c4848f0] tube for efficient heat transfer. Tiny amounts of greasy dirt/chaff [b:654c4848f0]behind[/b:654c4848f0] each tube attract more dirt, and very soon, your condenser is plugged yet again.

Here's where you need to learn the "six - way angle" of attack for cleaning cooling components. By six-way, I am talking about cleaning your condenser with hot high pressure soap and water. Wash the core directly from the front, the back, and from 45 degrees each direction. Check you progress with the paper towel/air nozzle test. Clean? Now, [b:654c4848f0] remove [/b:654c4848f0] the radiator and clean with the same method. You think there was a mess on your cement before? As a song from my day went, "You ain't seen nothin' yet".

If you are having major problems keeping the front end clean, either you aren't getting it clean to begin with, and/or you have fluid leaks, and/or your 4240 isn't sealed to keep out chaff.

Does the hood fit snug around the fuel tank?
Do the side screens fit the hood and the tank?
How about that sealing foam I asked about earlier?
Does the fuel cap gasket or the fuel return line leak?
That pot-metal tee that the oil cooler hoses connect to, Is that small nipple loose?
Has someone welded up the steering lines and left the clamps loose/off?

There can be ZERO fluid leaks in front of the radiator. A few tablespoons of oil will collect dirt which = a John Deere condenser turned into an adobe brick, which = a smoked compressor, which = $$$ out of your pocket.

If your shop is oriented primarily toward truck and auto repairs, their lack of knowledge about how dirt/chaff causes chronic AC problems is probably forgivable. But if their bread and butter jobs are farm tractors, then you need to find another shop. 'Cause you are most likely dealing with people too indifferent or willfully ignorant to solve your problem.

Oh, and about those update/change-over suggestions? It is true there is a slight difference in quality of various compressor rebuilders. But I learned a long time ago that the same mechanics that can kill a Frigidaire A6 can also kill a Sanden, a York, or a Nippon-Denso just as quickly. Then what do you have to show for it?
I've heard all {I hope} the excuses:
*The compressors are no good
*R134 is no good
*The specified viscosity oil, PAG 150 is no good
*The expansion valves are no good
* etc, etc, etc.

Your tractor was designed to work for and serve [b:654c4848f0]you - - - NOT [/b:654c4848f0]the other way around. Why should it needlessly consume assets better invested in your family, church, and personal hobbies?
 
Rex, thanks so much for your time. Your detailed info sounds right on to me. Yes I can handle this kind of thing. I do not have AC tools etc and I am not about to "break into" the system. I will pay particularly attention for leaks in front of the radiator and seal things up to keep the crap out.

Is there a way I can contact you directly via email? I thought I might send some pictures for your review and comment.

Rick
 
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