Motorhome AC question

[HB Vic]

Anyone ever add freon to their Moho? Ford V-10 gasser. For some reason the AC stopped working about a year + back, it was under warranty then, but not now. Unfortunately had no time to deal with it.

So a few weeks ago I added a can. It was totally empty. It took a full can and the pressure was still low. That had to be a month ago.

The good news is today it was still up in pressure, the same as it was a month ago. So I tried to add more. Probably spent 45 minutes and still could not get the pressure to within the green area based on the temp today.

Think I got a bad refill can? Or are those autopart refill jobs not high enough pressure for a motorhome? or does it not matter, ac is ac?

[ChumpChange]

Not sure but MoHo A/C has never been the best as there's no recirculating option. If you're too hot, fire up the generator.

Never used a diy refill.

[2manymustangs]

YOu're talking about the compressor/system running off of the engine and not a roof top AC unit true???

Under most circumstances its pretty hard to OVER charge... BUT it is possible if you really work at it...

Put a small thermometer in the vent, open the windows and doors when you are trying to charge...

If you can get a 40+ degree drop below ambient thats pretty good but not ideal... I like to see 40 degrees at the vent on my little meat thermometer...

WHen it starts cooling pretty good, close the doors/windows and IF you do have a RECIRCULATE/MAX option see if it eventually will start to cycle/freeze up while sitting/parked...

On cars/trucks once I can get the system to cycle/freeze up by closing windows/doors and going to MAX/recirculate I stop charging...

R134 I assume... Look at all of the unions and try to find a union that looks oily/greasy/dirty...


DONT use any of the "stop leak" charges, but a oil/R134 charge is good to do eventually...

[HB Vic]

Under most circumstances its pretty hard to OVER charge... BUT it is possible if you really work at it...

Put a small thermometer in the vent, open the windows and doors when you are trying to charge...

If you can get a 40+ degree drop below ambient thats pretty good but not ideal... I like to see 40 degrees at the vent on my little meat thermometer...

WHen it starts cooling pretty good, close the doors/windows and IF you do have a RECIRCULATE option see if it eventually will start to cycle/freeze up while sitting/parked...

On cars/trucks once I can get the system to cycle/freeze up by closing windows/doors and going to MAX/recirculate I stop charging...

R134 I assume... Look at all of the unions and try to find a union that looks oily/greasy/dirty...

Well there ya go. I had a feeling you'd know. Ya, it was hot when I was doing it. I'll try it again tomorrow am when its cool and I'll take a thermometer with me. Thank you sir.

[2manymustangs]

Well there ya go. I had a feeling you'd know. Ya, it was hot when I was doing it. I'll try it again tomorrow am when its cool and I'll take a thermometer with me. Thank you sir.

Give me a shout while your charging if you have any questions...

What year is the moho? THe compressors on the ford modular engines are pretty good...

Auto AC is one of my hobbies, quite often the orfice/screen gets plugged when a novice is doinking around on the system OR there is a compressor failure and the system gets contaminated... THe orifice tube is easy to change IF you can locate it

[HB Vic]

It's a 2012, only 10,000 mi on it


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[2manymustangs]

It's a 2012, only 10,000 mi on it


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Front and rear AC (auxillary fan/evaporator in the rear like a conversion van)? OR just "out of the dash" AC?

[HB Vic]

It has both, chassis and house roof deal.

Wait. I think I forgot to sleep last night lol


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[2manymustangs]

It has both, chassis and house roof deal.

Wait. I think I forgot to sleep last night lol


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Does the CHassis system have outputs in the back or mid area of the MOHO like a big conversion van??? IF YES, this is typically a point of failure because the refrigerant lines are not factory engineered system but rather a cobbled together addition to the factory system/lines and are often not as well engineered as the factory/chassis system... They are add on's to the factory chassis system...

IF NO, if the chassis system doesnt have additional rear cooling i would suspect that your compressor is just fine since it's only 10k miles... I have had the factory compressors go over 200k miles and work just fine...

In front of the radiator there is a condensing coil that is another common point of failure in those unions/connections... Most of those unions have dual urethane (green) o-rings and are typically pretty rock solid but minor front end damage can easily mess up that condensing coil and unions...

When the system is running look at the dryer/evaporator core area (see picture below) to see if it is frosty white/freezing cold... This is often a indication that your orifice/aperture is plugged (easy fix)... The big black can is the dryer and has the pressure switch attached...




The orfice (see below) can be located in a few different places and will require you to do some online research to nail down its location... Sometimes located in the high pressure line a few feet from the firewall and sometimes located right on the inlet to the evaporator core unions (on the firewall)... If this thing gets plugged it will cause your system to malfunction, usually they are plugged on older/high mileage cars/trucks or contaminated systems...