2655 Air Conditioner went Boom

[OldTrix]

Well, not really boom, more like a very loud Pssssst! I have a 2655 cab/shuttle with 300 hrs on it. Fired it up to move a trailer around yesterday, and switched the AC on as it was warm for a change. Idled to the back of the lot to hook up, and the high pressure relief valve on the AC blew. Scared me for a second till I understood what was happening. Immediately shut the tractor off, and the valve popped shut in a couple seconds. Ran the trailer to where i needed it and parked. while idling, I could still hear the compressor clutch kick in when i would cycle the AC switch in the cab, but no cold air.

Has anyone ever experienced something like this? I'll check the condenser to make sure it isn't blocked when I can get back to it, but I can't think of anything else in the system that would plug a like like that to build that much pressure. Do the H valves go bad on these things? Plugged desiccant cartridge? I haven't had time to dig into it, looking for likely trouble spots to check first.

 

[Dman1981]

Put gauges on to read pressures if they are not over relief could be bad.
Pump will cycle when refrigerant is low

 

[OldTrix]

I've got a set of gauges and a few cans of 134a I'll bring up next trip. Will first check the condenser for pluggage, I did hose the thing off last time before parking it. Maybe plugged with mud? Dunno,will check it out.

AC wasn't working, which led me to believe a possible blockage, but that makes no sense as it worked fine before. Will have to go through the basics and see.

 

[Dman1981]

they have high low switch on them It should turn off before relief goes off
In theory
The other thing I have seen is the desiccant in the drier busts and puts little beads everywhere down stream
Have had to remount them in less shaky spots

 

[OldTrix]

Where is the dessicator located? It doesn't show up on the parts fiche that I can see. Down near the condensor?

 

[Dman1981]

It's in the filter drier assembly is just a bag in there with little beads absorbs moisture but if it is in place where it vibrates constantly will break insides apart
I know on a tractor right but most of the o es I moved they had them mounted to engine which was
Rubber mounted and shook quite a bit
Those crazy Englishmen

 

[OldTrix]

I'm going back up tomorrow, will track it down via the piping. Looks like a smallish black canister, smaller than what I'm used to seeing for ac systems.

What to do if the beads are everywhere? disconnect and blow out the lines, then pump down and recharge?

 

[cbg8670]

I'm going back up tomorrow, will track it down via the piping. Looks like a smallish black canister, smaller than what I'm used to seeing for ac systems.

What to do if the beads are everywhere? disconnect and blow out the lines, then pump down and recharge?

Yep, blow backwards through evaporator

 

[Dman1981]

They can be sticky little things but yes they usually stop at txv
but yes everything on the downside would need to be flushed

 

[OldTrix]

It appears the compressor is toast. Low side shows higher pressure than high side with clutch engaged.

Also, the drier appears to be a unit with the condenser- there is slim cylindrical attachment welded to the far side of the condenser with what appears to be some sort of tabbed plug at the bottom, as if you could unscrew it. No other sign of a cannister drier anywhere in the circuit.

 

[OldTrix]

Blew out the lines- nothing in them. I found a much cheaper alternative to the OEM compressor by cross-referencing the part numbers on the stock compressor. FYI, there was a design change and instead of having a machined groove and o-ring in the rear housing of the compressor, the connection is now smooth-faced. Sealing washers are used in lieu of o-rings. AP Air in Iowa helped me out on that, and while they didn't have the lowest cost compressor, they were the only ones to list and show the sealing washers. $4.70/set. Waiting on the washers to arrive to bolt up the new compressor and see how it goes.

 

[OldTrix]

OOOOohhh-Kaaaayy. Expansion valve is shot, been searching a month for replacement. plugging in the Mahindra/TYM part number yields some interesting results, none of which match the physical block valve I removed. The dealers have no numbers for a valve, only an evaporator for $2000.

Fortunately, the valve itself has a tag on it, made by TGK, part number C33157Eo (also 52324390 on the label). No luck finding a cross-reference.

Finally, went back to AP Air Inc. in Iowa. They couldn't cross on the P/N, but we plugged in the model of tractor and it popped up their part number 903-822, which also showed the C331 number in the description.

I can't imagine any of these cab tractors having anything different in them across models, so if you're looking for a a block expansion valve for a 2500/2600 series cab model, my bet it it's going to be this part number. $27 plus shipping. Beats $2k from my helpful dealer......

 

[OldTrix]

So, all back together, and everything works as it did. Amazon sells this air comb gizmo that can fit in behind the radiator, intercooler and condenser and blow out the crud. Highly recommend the 24" version for out little tractors. A tad pricey for a tube with holes in it, but I didn't have to jig up a thin wall tube and drill tiny holes in it, either..

Amazon.com

BTW, tractor is for sale if anyone is interested.

 

[endlessmetal]

So, all back together, and everything works as it did. Amazon sells this air comb gizmo that can fit in behind the radiator, intercooler and condenser and blow out the crud. Highly recommend the 24" version for out little tractors. A tad pricey for a tube with holes in it, but I didn't have to jig up a thin wall tube and drill tiny holes in it, either..

Amazon.com

BTW, tractor is for sale if anyone is interested.

Would you be able to tell me the location of the expansion valve? Atm my Mahindra 2665 is at the shop due to the hurricane that passed caused a tree to fall on the top of the cab. The shop is trying to figure out where the expansion valve is after I told them what it was doing after the damage to the tractor. There saying it's the compressor/condenser or the whole unit is bad but that is all new. I spoke with a few people, and they all said it's the expansion valve as well as I figured that's what is the main cause of issue. The tractor ac runs great until the sun comes up then it starts to lock the compressor up smoking the belt. If you turn it off for a while it'll go back to working like normal, then it'll start to dead head again locking up the compressor. i was going to fix it myself if this Mahindra shop can't do what's needed. haven't been too happy with this tractor and the problems so far. appreciate any help or information your able to give and hopefully this helps someone else with the same issues.

 

[R134a]

Would you be able to tell me the location of the expansion valve? Atm my Mahindra 2665 is at the shop due to the hurricane that passed caused a tree to fall on the top of the cab. The shop is trying to figure out where the expansion valve is after I told them what it was doing after the damage to the tractor. There saying it's the compressor/condenser or the whole unit is bad but that is all new. I spoke with a few people, and they all said it's the expansion valve as well as I figured that's what is the main cause of issue. The tractor ac runs great until the sun comes up then it starts to lock the compressor up smoking the belt. If you turn it off for a while it'll go back to working like normal, then it'll start to dead head again locking up the compressor. i was going to fix it myself if this Mahindra shop can't do what's needed. haven't been too happy with this tractor and the problems so far. appreciate any help or information your able to give and hopefully this helps someone else with the same issues.

 

[R134a]

The expansion valve regulates the amount of refrigerant going in to the evaporator coil. I have never seen a Mahindra a/c system but I would say to look at the lines 2 lines at the evaporator core. Is there what looks like an aluminum block in between the evap and the lines ? Its either that aluminum block or a disc w/ copper winding and a bulb. Again look by the evap core. ****

"They are saying the compressor /condensor or the whole unit is bad but it is all new" The compressor locking up is a bad sign. It tells me the job was not done properly when repaired the first time. The circulation path the refrigerant takes has to be IMMACULATE. The initial failure likely had metal particles from the compressor circulate thru the system. Good 'O Boy replaces the compressor, condensor, drier, but did not replace expansion valve and/or did not flush evaporator core and/or did not follow proper flush procedures. The a/c works 1 maybe 2 seasons and then self destructs again. The problem is to find somebody who knows and cares about what they are doing. I know thats not happening where I live.

 

[endlessmetal]

The expansion valve regulates the amount of refrigerant going in to the evaporator coil. I have never seen a Mahindra a/c system but I would say to look at the lines 2 lines at the evaporator core. Is there what looks like an aluminum block in between the evap and the lines ? Its either that aluminum block or a disc w/ copper winding and a bulb. Again look by the evap core. ****

"They are saying the compressor /condensor or the whole unit is bad but it is all new" The compressor locking up is a bad sign. It tells me the job was not done properly when repaired the first time. The circulation path the refrigerant takes has to be IMMACULATE. The initial failure likely had metal particles from the compressor circulate thru the system. Good 'O Boy replaces the compressor, condensor, drier, but did not replace expansion valve and/or did not flush evaporator core and/or did not follow proper flush procedures. The a/c works 1 maybe 2 seasons and then self destructs again. The problem is to find somebody who knows and cares about what they are doing. I know thats not happening where I live.

Appreciate the reply. I'll look into this more. From a 2565 diagram shows it in the roof shell behind the fans with two lines. I let the shop know that it may possibly be there as well. i didnt get to look at it all personally yet. Hopefully its covered under insurance. This all started after the roof got crushed in during the storm when a tree fell. All that is fixed now but none of the ac was replaced yet. I'll talk with Mahindra and see what they are going to do if not ill order all the parts and handle it myself.

 

[OldTrix]

The ac expansion ("H") valve resides in the roof shell just inside the LH door. The AC lines run up the A pillar to the valve, which is secured to the evaporator. Since I did not have covered storage at the time, I removed the headliner to access it. Removing the roof is far easier to do, time-wise, and access to components will be easier as well.

 

[Hay Dude]

The expansion valve regulates the amount of refrigerant going in to the evaporator coil. I have never seen a Mahindra a/c system but I would say to look at the lines 2 lines at the evaporator core. Is there what looks like an aluminum block in between the evap and the lines ? Its either that aluminum block or a disc w/ copper winding and a bulb. Again look by the evap core. ****

"They are saying the compressor /condensor or the whole unit is bad but it is all new" The compressor locking up is a bad sign. It tells me the job was not done properly when repaired the first time. The circulation path the refrigerant takes has to be IMMACULATE. The initial failure likely had metal particles from the compressor circulate thru the system. Good 'O Boy replaces the compressor, condensor, drier, but did not replace expansion valve and/or did not flush evaporator core and/or did not follow proper flush procedures. The a/c works 1 maybe 2 seasons and then self destructs again. The problem is to find somebody who knows and cares about what they are doing. I know thats not happening where I live.

I’ve thrown a ton of money into fixing the AC system in my International truck.
After a few months, it’ll blow warm again.
Hard for me to find a good AC specialist