My AC Won't keep blowing cold on my 2006 RV E-450 gas. I just replaced the high and low cut-off switches and when I put the pressure gauge on the AC, it said that everything was running perfect and it was running cold too. But then let it run for ten minutes and it stops blowing cold and now the pressure gauge reads above the high area into the yellow and headed towards red (too much pressure) and I can no longer hear the compressor kicking on and off. I actually let out some of the freon, since the gauge now read too high. But this has been a cat and mouse game for some time. We changed out the relays and that didn't help. It's blowing fine, there doesn't appear to be any vacuum leaks, as I've read about those (and it was running fine going up hills prior to this). Right now it's just sitting flat on my property and not even working the engine. No blockages. But it makes travel in summer months pretty awful. Any ideas?

If I had to take a guess. and given your post all I can do is guess.You need to clean the condenser coil.. On other than coleman this involves some work... First remove the outer cowl (Cover) on the A/C.. Generally this is about a dozen phillips head screws around the bottom (A magnetic parts tray is nice to keep track of 'em (Harbor freight, most auto stores, many hardware). Then you need to remove the INNER cover over the condenser.. This can be easy (A few more screws) or major (Cut the sealing tape. Unbend the tabs and so on) now you can see the crud blocking the thing.. You may need to pull the condenser fan (I did but I wear an xxl or xxxl glove) or use a soft brush to coax the crud off the fins...Then you get to put it all back together.Coleman instructionRemove 4 bolts (Philips head) from the top of the unit and lift off cowlPeal the condenser clean, replace cowl, replace bolts.

Thanks for the quick reply. Okay, if I didn't make myself clear, let me start again. This is the Chassis AC - the one installed by the Ford Chassis, not the roof mounted coach one. So this is the AC blowing out of the dash while you drive down the road.

backup a bit.You may have a worn compressor clutch creating too large of a air gap which often will engage for a short time then will disengage as the pressure in the system increases from heat.Verify that the compressor is staying engaged with the clutch, if the center part of the pulley stops spinning you have a worn clutch.Sometimes the center part of the pulley will still be spinning, but not as fast as it should and that is also a sign of worn clutch. To find out for sure, you will want to verify the clutch air gap. This is done with feeler gauges..Sometimes the air gap can be restored by changing/adding/removing shims.SEE HEREFound a good video on how to check the air gap, remove the clutch and how to adjust the gap..HEREMake sure the air gap is correct before trying other stuff..

My guess would be the expansion valve needs to be replaced. Probably should replace the receiver/drier also.

What are the pressures both low and high while it is cooling and what are they when they start going up and quits cooling? I'll venture a guess and say that the unit was low on gas and someone added some or too much and also did not do it properly and introduced some air into the system. Air in the system will cause what you're reporting. Also I don't think a dirty evaporator( someone called it a condenser) will cause this problem.What gas does your ac system use? Are you refilling with the sam? Maybe R134A?I doubt that the clutch is the problem.

AC Quits Blowing Cold after a few minutes | Good Sam Community

Gdetrailer
Explorer III
May 01, 2022
backup a bit.

You may have a worn compressor clutch creating too large of a air gap which often will engage for a short time then will disengage as the pressure in the system increases from heat.

Verify that the compressor is staying engaged with the clutch, if the center part of the pulley stops spinning you have a worn clutch.

Sometimes the center part of the pulley will still be spinning, but not as fast as it should and that is also a sign of worn clutch.

To find out for sure, you will want to verify the clutch air gap. This is done with feeler gauges..

Sometimes the air gap can be restored by changing/adding/removing shims.

SEE HERE

Found a good video on how to check the air gap, remove the clutch and how to adjust the gap..

HERE

Make sure the air gap is correct before trying other stuff..
adventureman5
Explorer
May 01, 2022
Thanks for the quick reply. Okay, if I didn't make myself clear, let me start again. This is the Chassis AC - the one installed by the Ford Chassis, not the roof mounted coach one. So this is the AC blowing out of the dash while you drive down the road.
wa8yxm
Explorer III
May 01, 2022
If I had to take a guess. and given your post all I can do is guess.

You need to clean the condenser coil.. On other than coleman this involves some work... First remove the outer cowl (Cover) on the A/C.. Generally this is about a dozen phillips head screws around the bottom (A magnetic parts tray is nice to keep track of 'em (Harbor freight, most auto stores, many hardware). Then you need to remove the INNER cover over the condenser.. This can be easy (A few more screws) or major (Cut the sealing tape. Unbend the tabs and so on) now you can see the crud blocking the thing.. You may need to pull the condenser fan (I did but I wear an xxl or xxxl glove) or use a soft brush to coax the crud off the fins...

Then you get to put it all back together.

Coleman instruction

Remove 4 bolts (Philips head) from the top of the unit and lift off cowl
Peal the condenser clean, replace cowl, replace bolts.

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AC Quits Blowing Cold after a few minutes

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