# Truck air conditioning



## JD3430 (Jan 1, 2012)

OK, so my '08 F-350 AC took a dump. Was fairly cold when I bought truck, then slowly got warmer. Now its just ambient air temp.

I tried AC pro. I put most of a bottle in. Gauge reads max pressure when I hook it up, so it doesn't appear to be a leak. Belt looks good.

Anyone know AC systems? What would be next to check.


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## sethd11 (Jan 1, 2012)

Check the clutch and see if it is engaging all the way


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## Tx Jim (Jun 30, 2014)

IMHO anyone that puts refrigerant in an AC without utilizing proper gauges is doing the same as banging their head against a brick wall. Too much refrigerant causes poor cooling. I agree is compressor pumping? If system has adequate refrigerant it could have faulty high pressure switch or expansion valve which correct gauges will aid in diagnostics.


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## JD3430 (Jan 1, 2012)

Tx Jim said:


> IMHO anyone that puts refrigerant in an AC without utilizing proper gauges is doing the same as banging their head against a brick wall. Too much refrigerant causes poor cooling. I agree is compressor pumping? If system has adequate refrigerant it could have faulty high pressure switch or expansion valve which correct gauges will aid in diagnostics.


The reason I did this is because the best mechanic I know (ad he is really good) suggested I do this first. Also I've had 2 cab tractors in the past that had weak AC and I was able to get a permanant fix by adding refrigerant.


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## ozarkian (Dec 11, 2010)

A very simple approach that gets my tractors and trucks blowing cool air is, to power wash out the condenser and radiator. Spend lots of time and water. If everything else is working properly, this might take care of the problem.


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## Tx Jim (Jun 30, 2014)

JD3430 said:


> The reason I did this is because the best mechanic I know (ad he is really good) suggested I do this first. Also I've had 2 cab tractors in the past that had weak AC and I was able to get a permanant fix by adding refrigerant.


I agree with ozarkian that good air flow across condenser/radiator is a big + for well operating AC. Person that advised you to add refrigerant without attaching high & low pressure gauges may be a good mechanic but evidently has not been to an air cond. repair school. As for you adding refrigerant to 2 tractors without proper gauges for a permanent repair you were just LUCKY.!!! Maybe you should think about buying a lottery ticket.


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## JD3430 (Jan 1, 2012)

I don't think it's radiator dirty
Maybe on a tractor.
This is a pickup and has a clean radiator


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## PaMike (Dec 7, 2013)

When I bought my Maxxum cab tractor the A/C would always trip off and throw the over pressure light when I was idling of the tractor was setting still for too long. Had the system serviced, and it still did it. Couldnt figure out the problem until one day when I was mowing hay and the tractor started running hot. Radiator looked clean, but I hit it with a low pressure washer. Here the rad was clean on the outside, but the fins were all filled with seedheads. You couldnt see it looking at it. 20 min with the pressure washer made the tractor run cooler and allowed the air to flow through the radiator and condensor. I have had an issue with the A/C since...


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## gearhartfarms82 (May 10, 2015)

To start with unles you put guages on it you are wasting your time. You MUST know what the high side is doing to know what your system is telling you. Yess the low side is important but when there is trouble in paradise you have to see what the high side is.

Simple cheap things are power wash all ur radiators. Check for cabin filters. Make sure a/c pump is turning. Fan pulling proper air flow. No blow fuses/relays.

If a/c still is not correctly cooling get guages. That will start telling you what u need to know.


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## luke strawwalker (Jul 31, 2014)

JD3430 said:


> I don't think it's radiator dirty
> Maybe on a tractor.
> This is a pickup and has a clean radiator


 Sometimes the CONDENSER coil in FRONT of the radiator, which rejects the heat from the AC system to the atmosphere and cools the refrigerant coming from the compressor, WILL be plugged up even if the radiator is clean. The condenser is in front of the radiator and can collect a TON of bugs, grass/seed/hay, and various sundry other crud and really impair the correction functioning of the AC system.

They sell cans of refill refrigerant with a low pressure gauge on the top of the can... at the VERY LEAST get one of those and connect it up to the low pressure fitting on the filter/dryer coming out of the evaporator, where the hose usually comes out and goes on down to the compressor. The gauge should give you an idea of how much refrigerant you actually have in the system. Crank the truck up, turn the AC on full with the doors open, and see what the pressure is running on the low side. Check to see if the compressor is coming on. If the pressure is too low in the system, meaning the freon has leaked out, the compressor probably won't come on AT ALL to protect it. If the low pressure reading is in the correct range, you don't need freon. Sometimes it helps to reach over and pull the accelerator cable a little to rev up the engine and speed up the compressor, and see what the low side pressure does. Sometimes they'll read a "good" pressure reading AT IDLE and then when revved up, will drop into the "low" area, which usually means some freon will make it work better. If it's low at idle, you probably need freon.

TO really DO IT RIGHT, you need to hook up a manifold gauge set to the system and see what the low side AND high side pressures are doing. You COULD have anything from a plugged up orifice tube (high side TOO high, low side TOO low) to insufficient freon (both sides too low) to a bad compressor (low side high, high side low) to a plugged condenser (both sides too high) to plugged up cabin air filters or insufficient airflow...

"Adding a can of refrigerant" is a "quick-n-dirty" fix but it's sort of a shot in the dark-- sometimes it works, sometimes it doesn't. But, it's worth a try I guess... like a mechanic buddy of mine said-- "you know what A/C stands for?? ALWAYS COSTS!"

Later and good luck! OL J R


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## JD3430 (Jan 1, 2012)

I did buy the refrigerant with the gauge. Says system is well pressurized. 
Radiator & condenser look clean.


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## Tx Jim (Jun 30, 2014)

luke strawwalker said:


> Sometimes the CONDENSER coil in FRONT of the radiator, which rejects the heat from the AC system to the atmosphere and cools the refrigerant coming from the compressor, WILL be plugged up even if the radiator is clean. The condenser is in front of the radiator and can collect a TON of bugs, grass/seed/hay, and various sundry other crud and really impair the correction functioning of the AC system.
> 
> They sell cans of refill refrigerant with a low pressure gauge on the top of the can... at the VERY LEAST get one of those and connect it up to the low pressure fitting on the filter/dryer coming out of the evaporator, where the hose usually comes out and goes on down to the compressor. The gauge should give you an idea of how much refrigerant you actually have in the system.


Luke

How is attaching a can of refrigerant with a gauge on low side going to reveal how much refrigerant is in system when attaching both gauges(high & low) pressure won't actually reveal "how much actual refrigerant" is in system? There are too many variables such as AC system condition & ambient temp for low pressure reading to reveal much. Only means I know of to determine how much refrigerant is in AC system is to measure the amount before installing it.

Jim.


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## bluefarmer (Oct 10, 2010)

Remove nut in center of clutch, slide the clutch off and behind that there should be a spacer/washer. Remove that and put clutch back on. It is put there from the factory for that very reason.


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## ozarkian (Dec 11, 2010)

PaMike said:


> When I bought my Maxxum cab tractor the A/C would always trip off and throw the over pressure light when I was idling of the tractor was setting still for too long. Had the system serviced, and it still did it. Couldnt figure out the problem until one day when I was mowing hay and the tractor started running hot. Radiator looked clean, but I hit it with a low pressure washer. Here the rad was clean on the outside, but the fins were all filled with seedheads. You couldnt see it looking at it. 20 min with the pressure washer made the tractor run cooler and allowed the air to flow through the radiator and condensor. I have had an issue with the A/C since...


I learned this trick on my Maxxum tractor too. I always blew residue out of condenser and radiator. The crud builds up where you cannot see it. If you can power wash with hot water, that is best.


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## r82230 (Mar 1, 2016)

JD3430 said:


> I did buy the refrigerant with the gauge. Says system is well pressurized.
> Radiator & condenser look clean.


JD, most likely the refrigerant only had a low side gauge. There is also a high side gauge, my tractor wasn't working so well, I cleaned everything (filter, radiator, etc.). Ask mechanic friend about using one of those refrigerant with gauge, he said 'you can try it, but I won't guarantee the results', The stubborn fool married to my wife, had to try it, gauge said need Freon, add as package instructions, using just the gauge attached and he got no results (in fact, was worse off). Drove tractor to mechanic (as he recommended in first place), he vac the system out, re-filled by what both gauges said, working like new!!! Worse part, he didn't charge the fool to fix (he would not had charged in the first place either), seems the fool gives him enough firewood, from dead ash / elm trees.

Larry

PS took other tractor over to vac, re-fill also, even though adding by gauge on the can work out OK, on this tractor. Lesson learned, the hard way.


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## JD3430 (Jan 1, 2012)

I figured no harm in spending $39 for a possible fix. Like I said, worked with 2 cab tractors in the past, so I figured "what the...."


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## carcajou (Jan 28, 2011)

JD3430 said:


> I figured no harm in spending $39 for a possible fix. Like I said, worked with 2 cab tractors in the past, so I figured "what the...."


I would have done the same.


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## JD3430 (Jan 1, 2012)

r82230 said:


> JD, most likely the refrigerant only had a low side gauge. There is also a high side gauge, my tractor wasn't working so well, I cleaned everything (filter, radiator, etc.). Ask mechanic friend about using one of those refrigerant with gauge, he said 'you can try it, but I won't guarantee the results', The stubborn fool married to my wife, had to try it, gauge said need Freon, add as package instructions, using just the gauge attached and he got no results (in fact, was worse off). Drove tractor to mechanic (as he recommended in first place), he vac the system out, re-filled by what both gauges said, working like new!!! Worse part, he didn't charge the fool to fix (he would not had charged in the first place either), seems the fool gives him enough firewood, from dead ash / elm trees.
> 
> Larry
> 
> PS took other tractor over to vac, re-fill also, even though adding by gauge on the can work out OK, on this tractor. Lesson learned, the hard way.


Im hoping the stubborn fool married to my wife gets a similar result. :huh:


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## gearhartfarms82 (May 10, 2015)

If low is ok need to fig out what high side is


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## Farmineer95 (Aug 11, 2014)

Gauge on can might tell pressure if vehicle is off and system is equalized.

Does fan clutch work? Does it get any cooler at 55 mph?


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## luke strawwalker (Jul 31, 2014)

Tx Jim said:


> Luke
> 
> How is attaching a can of refrigerant with a gauge on low side going to reveal how much refrigerant is in system when attaching both gauges(high & low) pressure won't actually reveal "how much actual refrigerant" is in system? There are too many variables such as AC system condition & ambient temp for low pressure reading to reveal much. Only means I know of to determine how much refrigerant is in AC system is to measure the amount before installing it.
> 
> Jim.


It doesn't tell you "how much refrigerant is in the system", you're correct... it only tells you if the "pressure is in the right range" on the low side, which as I said, is only half the equation anyway, since high side pressure reading is needed to really diagnose the problems anyway. BUT, since low side pressure directly correlates to evaporator temperature, it's a "cheap and dirty" method of determining if the system needs more refrigerant, ASSUMING the system is working properly to begin with.

Another thought comes to mind, which might be applicable to the OP's problems... he could have a dirty/clogged evaporator with poor airflow, OR, a faulty/damaged blend door that is allowing cool air from the evaporator to mix with hot air from the heater core... or bypassing the evaporator core altogether. I've seen both happen.

Basically, from what the OP said, if adding a can of freon to the system didn't fix it, and the low pressure side is in the "correct range", the condenser coil is clean with sufficient airflow, and the system still isn't working properly, other than checking the evaporator coil for cleanliness/proper airflow and making sure the blend door is operating properly, I'd say it's time to take it to the shop. Without gauges it's impossible to really diagnose what's going on in the system. Given how difficult it is to access the evaporator and/or blend door without gutting the dash and underdash of most trucks, I'd probably just take the thing to the shop and let them figure it out. Some things are just worth the cost of repair rather than fiddling about with it piecemeal and ending up with it being something easily diagnosed and fixed in the shop anyway... IMHO...

Later! OL J R


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## luke strawwalker (Jul 31, 2014)

JD3430 said:


> I figured no harm in spending $39 for a possible fix. Like I said, worked with 2 cab tractors in the past, so I figured "what the...."


Yeah, lots of times if the thing isn't cooling well, it's low on freon. Newer systems are a LOT better about leaks than the old systems were. I have yet to have to add freon to my 02 F-150 or the 95 Grand Caravan. My old 77 Suburban we drove from 85 to about 95, had to add a can or two every year. That was pretty typical on ALL those older R-12 systems. Course, seal and material technology has improved a LOT since then.

Adding freon is just a 'cheap and dirty" fix anyway... it shouldn't be leaking down without some issue that probably should be fixed, although I wouldn't bother spending the cash to fix something that was only leaking like a can a year out and worked right the rest of the time. BUT, if adding freon don't fix it, IMHO it's time for a trip to the shop... more going on there that needs attention by someone with the right tools for the job... (and usually more smarts).

Sorta like my wife's 95 Roadmaster... her AC quit last spring... took it to the shop, they installed a new compressor because the old one rekitted itself... flushed the system to get rid of junk from the old compressor, and it would freeze you out. She drove it til school ended, and it sat parked most of the summer, with only a couple drives. One day RIGHT BEFORE school let out, no AC. She toughed it out the last day or two of school. I got in it and tried it and it worked perfectly. She drove to a training one day in summer and it worked great. She goes to drive it again, no AC. I got to checking and the AC compressor clutch wasn't coming on. Looked at the wiring diagram in the book, and figured, "maybe the AC compressor clutch relay in the underhood box is shot", so I picked one up at OReilley's for $23 bucks and installed it. When I popped the old one out, it had a crack in the plastic shell of the relay and a little hole in it, so it was probably on the way out anyway. I installed the new relay, no joy... still no AC compressor. Since EVERYTHING on that car is a PITA to work on, especially for a fat-fingered fatboy like me, and since I figured that maybe the automatic temperature control system decided to take a dump, and I don't have the equipment, time, or patience to fart around with electronic garbage, I took it back to the mechanic. Turns out the reman compressor had a dead short in the AC clutch and nothing was wrong with the system per se... he evacuated the system, replaced the compressor under warranty, pulled the vacuum, and refilled the system with refrigerant. Works like a champ. Now if he can just get the passenger side window regulator and get it installed... 

Like Clint Eastwood said, "A man's GOT to know his limitations." I fix as much as I can, but I know when I'm in over my head or don't have the tools and it's easier and cheaper in the end to just take it to the shop and get it fixed RIGHT...

Later! OL J R


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## glasswrongsize (Sep 15, 2015)

JD, I might have looked over it if you said it (been REAL busy the past couple of weeks and trying to catch up...skimming more than reading), but is your compressor turning? If the compressor is not turning, the low side can show high because it is as equilibrium. If the compressor turning, get out the test light and check for power at the clutch and check for an open circuit at the low press switch, high press switch, etc...

73, Mark


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## Tx Jim (Jun 30, 2014)

luke strawwalker said:


> Yeah, lots of times if the thing isn't cooling well, it's low on freon. Newer systems are a LOT better about leaks than the old systems were. I have yet to have to add freon to my 02 F-150 or the 95 Grand Caravan. My old 77 Suburban we drove from 85 to about 95, had to add a can or two every year. That was pretty typical on ALL those older R-12 systems. Course, seal and material technology has improved a LOT since then.
> 
> Adding freon is just a 'cheap and dirty" fix anyway...
> 
> Later! OL J R


Air conditioned vehicles after '93 utilize refrigerant not freon.


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## somedevildawg (Jun 20, 2011)

Semantics......


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## Tx Jim (Jun 30, 2014)

somedevildawg said:


> Semantics......


Maybe so but I don't see R134A listed below do you?


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## Rodney R (Jun 11, 2008)

JD,

Since the addition of a can did not work, you have to get the manifold gauge set, and find out what's going on. I'd make sure the condenser is clean first, and then hook up the gauges. Could be that something is plugged or you have a collapsed hose. I'm sorta betting on the condenser. If the compressor runs (I assume it does, but you never said? If you turn the key on, and the A/C, and turn the radio down- do you hear a 'click'? I know on a lot of machines you will, I assume the trucks work the same way?) Anyway, if the compressor runs and an extra can of refrigerant didn't help and the system shows full, then that sorta points to something on the exterior of the system. I had a plug in a system years ago on the return side, and the compressor soon put the system in a vacuum.

Rodney


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## Cozyacres (Jul 16, 2009)

Tx Jim said:


> Air conditioned vehicles after '93 utilize refrigerant not freon.


All freon is refrigerant, but not all refrigerant is freon, freon is just a brand name for certain kinds of refrigerant,

I have been a refrigeration service tech for over 30 years, a lot of thing have changed in that time.


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## glasswrongsize (Sep 15, 2015)

Not all refrigerants are freon; not all adjustable wrenches are "crescent wrenches; not all hot tubs are jacuzzis, not all white salad dressing in a quart jar is Mayonaise or "mayo"....
If I sent someone to the shop to get me a can of freon and my 18" crescent wrench and they came back empty-handed because I only have 134a and my "crescent" wrenches are 12" and the 18" is Blue Point... I would kick them right in the junk because I know damn good and well that they know what I'm talking about.....then we'd have a beer and we'd laugh and laugh about it and they could soak in my jacuzzi to ease their groin pain. When they got out of the jacuzzi, we'd laugh smore and I'd give them another beer.................then I'd kick them in the junk again 'cuz I still ain't over the first time. Pretentiousness.....

73, Mark


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## slowzuki (Mar 8, 2011)

I'm fairly sure it's the same down there but not 100%, here it's illegal to add r12 to a leaking system without diagnosing and attempting to correct the leak first. I think that rule carried over for r134a as well.

I'm always surprised which systems leak down and which don't, tractors with all their vibration never seem to hold a charge like a car. We have got a couple of 15+ year old cars that the AC has never been touched on.


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## luke strawwalker (Jul 31, 2014)

Tx Jim said:


> Air conditioned vehicles after '93 utilize refrigerant not freon.


Semantics... Refrigerant 134A, Freon-134a, vs. Freon 12... I've heard it called freon for years and guys still do around here...

Everybody knows you mean 134...

Later! OL J R


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## luke strawwalker (Jul 31, 2014)

glasswrongsize said:


> Not all refrigerants are freon; not all adjustable wrenches are "crescent wrenches; not all hot tubs are jacuzzis, not all white salad dressing in a quart jar is Mayonaise or "mayo"....
> If I sent someone to the shop to get me a can of freon and my 18" crescent wrench and they came back empty-handed because I only have 134a and my "crescent" wrenches are 12" and the 18" is Blue Point... I would kick them right in the junk because I know damn good and well that they know what I'm talking about.....then we'd have a beer and we'd laugh and laugh about it and they could soak in my jacuzzi to ease their groin pain. When they got out of the jacuzzi, we'd laugh smore and I'd give them another beer.................then I'd kick them in the junk again 'cuz I still ain't over the first time. Pretentiousness.....
> 
> 73, Mark


Amen and amen... OL J R 

PS... remember someone ripping my ass around here for pointing out that the "CV joint" on Deere (and other) mowers isn't ACTUALLY a CV joint... it's a double-cardan U-joint...

Oh well... I guess I should be used to it... can't win for losing with some folks... LOL


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## Cozyacres (Jul 16, 2009)

luke strawwalker said:


> Semantics... Refrigerant 134A, Freon-134a, vs. Freon 12... I've heard it called freon for years and guys still do around here...
> 
> Everybody knows you mean 134...
> 
> Later! OL J R


Youre right its just semantics, I call it freon, refrigerant, cold juice, whatever. Probably be better to call it by the actual name like R134a , R12, R-22, R410a, R404A etc etc etc........... SO don't kick me in the junk, I didn't invent all the stupid names Thank the Federal Government for this one!


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## JD3430 (Jan 1, 2012)

Truck went to dealer. I don't have the time or depth of AC repair knowledge needed for this repair. 
It also needs a new DPF

$$$$$


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## JD3430 (Jan 1, 2012)

So to finally put an end to an otherwise boring thread:
It took a few hours to find but it was a broken wire in a wire connector.
$450
We also installed a used DPF. Some super trucker kid took his off and threw it in the corner of his garage for a straight pipe.


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