Community Forums

Jim Harris · 08-20-2021, 12:34 PM

I have a 2004 Newmar Mountain Aire with a 400 horse Cummins on a spartan chassis.
A/C has a leak but can’t detect a leak in front or back with a electric leak detector .
Has anyone ever had a leak in hoses running the 40 ft from front to back?
Everything is encased under floor on chassis beams and not accessible.
I live in St Louis and haven’t found anyone that can address this problem. Any ideas?
I’m not talking about roof units but the dashboard a/c

Tha_Rooster · 08-20-2021, 01:37 PM

Quote:

Originally Posted by Jim Harris

I have a 2004 Newmar Mountain Aire with a 400 horse Cummins on a spartan chassis.
A/C has a leak but can’t detect a leak in front or back with a electric leak detector .
Has anyone ever had a leak in hoses running the 40 ft from front to back?
Everything is encased under floor on chassis beams and not accessible.
I live in St Louis and haven’t found anyone that can address this problem. Any ideas?
I’m not talking about roof units but the dashboard a/c

You inject die and use a light?

lllkrob · 08-20-2021, 01:51 PM

I seriously doubt the hoses themselves are leaking. I would bet the leak is at a connection or at the compressor or condenser. As Tha Rooster said have the system recharged with R134a containing dye. Run the system for 30 minutes and then use a UV light to look for leak traces. If nothing is found then operate the system for a couple of days and then use the UV light again.

I don't know who has been working on your coach but any good A/C shop should know this procedure, they don't have to specialize in RV's. A good auto A/C shop should be able to find the leak.

Dutch Star Don · 08-20-2021, 03:31 PM

I agree that hoses are leaking, as they're pretty tough. I had a leak that no one could find. I finally located it at the condenser, a spot that is hard to see. On a side radiator, the condenser is often hidden along the bottom of the radiator. My hose connections there were muddy from the leak.

Like others stated, it's probably a connection at a component.

lrsses · 08-20-2021, 06:09 PM

Just had to replace the a/c hoses on a 2008 Fleetwood Discovery 39V three years of no use by previous owner he paid for them. So yes old age is hard on rubber.

Corley · 08-20-2021, 06:29 PM

Typically, the seal on the compressor is a big leaking point. Any decent auto AC shop can handle leak location.

Xmcdog · 08-20-2021, 06:35 PM

As Corley said, compressor seal. Either there or the condenser. Electronic leak detectors are ok but nothing beats the old Mk 1 eyeball.

FIRE UP · 08-20-2021, 08:44 PM

Well Gang,
I'm in the same boat as the OP. Our coach, an '04 Itasca Horizon 36GD with the CAT C-7 330HP, had great dash air performance for about the first 6+ years of ownership, no issues what so ever. Then, one day, a few years ago, it put out warm air. Normally, I fix pretty much all my own stuff but, A/C is something I've never really learned about so, I employed a local shop to fix it. well, about $500 later, it was working flawlessly. It worked like that for about a year.

Now, warm air again. I have employed the same shop, at least three other times to fix and each time, they say: "You need this".... And I pay and they say it's ready. I pick it up, go on a trip, and it lasts ONE DAY and then, WARM AIR.

I have talked with them extensively about leak detection and they have used dyes and every other mechanism for finding out where all my 134 is not keeping put. They say they CANNOT find any leaks, it vacuums down and holds for the given amount of time. It's charged then and they call me. I use it for one day and then, the next day when we depart our camp/RV site, it's warm air.

My answer: I have now acquired a vacuum pump, gauges and couple dozen cans of 134. I will continuously charge it, as needed, while on any trip, until our travel season simmers down some and then, I will try and insert my own dye and see what I can find, if anything. I have numerous reports on the extreme difficulty of finding A/C leaks on diesel pushers, due to the vast spread-out layout of the systems involved. Mine is one of them.

It always cracks me up when folks say: "Any competent shop" can handle finding the problem and fixing it". Yeah sure. Sometimes, problems with RVs are just not that easy to find and repair, no matter how good a shop is.
Scott

RichKimball · 08-21-2021, 09:50 AM

I'm sorry to add that for those who feel any leak can be found....not really.

I had a leak that could not be found. UV dye...nope, multiple tries. Halogen electronic leak detector...nada.

During a failed compressor...that was replaced...new fittings and o rings. Condenser, dryer replaced...new o rings and some new fittings as well. Still leaked.

Finally, added 3 cans of Red Angel a year ago....no more leak. Well...sorry...that's not entirely true....had to add 8oz of gas last month as it was only 58deg discharge temp compared to previous 46deg.

So...there is still a leak somewhere...but Red Angel is my hero.

And I must concur with Scott (FireUp) regarding shops to service the RV dash air system.

FIRE UP · 08-21-2021, 10:53 AM

Quote:

Originally Posted by RichKimball

I'm sorry to add that for those who feel any leak can be found....not really.

I had a leak that could not be found. UV dye...nope, multiple tries. Halogen electronic leak detector...nada.

During a failed compressor...that was replaced...new fittings and o rings. Condenser, dryer replaced...new o rings and some new fittings as well. Still leaked.

Finally, added 3 cans of Red Angel a year ago....no more leak. Well...sorry...that's not entirely true....had to add 8oz of gas last month as it was only 58deg discharge temp compared to previous 46deg.

So...there is still a leak somewhere...but Red Angel is my hero.

And I must concur with Scott (FireUp) regarding shops to service the RV dash air system.

Hey Rich,
"Red Angle" huh? Hmmmm, Gonna have to look into that stuff. I was under the impression that "sealants" of just about any type, for A/C systems, are frowned upon by A/C techs. I kind-a see why. But, sometimes, ya gotta do what ya gotta do. Glad yours is at least keeping SOME of its 134 intact. This is getting expensive for me!

Scott

RichKimball · 08-21-2021, 10:58 AM

Quote:

Originally Posted by FIRE UP

Hey Rich,
"Red Angle" huh? Hmmmm, Gonna have to look into that stuff. I was under the impression that "sealants" of just about any type, for A/C systems, are frowned upon by A/C techs. I kind-a see why. But, sometimes, ya gotta do what ya gotta do. Glad yours is at least keeping SOME of its 134 intact. This is getting expensive for me!

Scott

Yep. I had an oil injector already from the repair work I did so I just purchased the liquid but I see that it's available with injector heads that simply attach to the low pressure port. I think its also guaranteed to work or money back. I realize it's pricey but still about $100 is good for me if it stops the leak (for the most part)
Red Angel Stop Leak

I see now that Blue Devil also has a multiple use injector tube and tool for a total of 8oz that would be easier and cheaper to use than 3 2oz bottles. Maybe use all 8oz in the large long runs of RV's?

Corley · 08-22-2021, 06:59 AM

Most of the AC stop leaks use a softening agent, which softens the compressor seal material so it can take a better "set" on the shaft. It also softens some goes of hoses, but is not supposed to affect the Teflon lined hoses. What often happens when you use that sealant, is it does its thing, and seals things for a while, but then that softener agent just keeps on softening things, and after a year or two, the seals are so soft that they give up the ghost. Knowledgeable AC techs will tell you that sealers are the worst thing you can do to any vehicle.

I confess I've used sealer a couple times, on vehicles that were not long for this world or headed down the road. But if you use it, plan on a compressor replacement (at a minimum) within a couple years, because that is probably in your future. And yes, AC leaks can be found by good AC techs. Probably that is not your typical automotive shop since that is just a sideline for them. Go to the right shop and they can find your leak, but it won't be cheap.

Just my opinion...

big willie · 08-25-2021, 03:16 AM

Quote:

Originally Posted by Jim Harris

I have a 2004 Newmar Mountain Aire with a 400 horse Cummins on a spartan chassis.
A/C has a leak but can’t detect a leak in front or back with a electric leak detector .
Has anyone ever had a leak in hoses running the 40 ft from front to back?
Everything is encased under floor on chassis beams and not accessible.
I live in St Louis and haven’t found anyone that can address this problem. Any ideas?
I’m not talking about roof units but the dashboard a/c

I am a certified commercial a/c tech. I know the the text book police will go crazy. If I can’t find a leak I use an adaptor and my air compressor with clean dry air. Charge the system with air. Everything shut off. You will find the leak. The sealers mentioned do work. Pull a minimum 300 micron vacuum before recharging. I live near St Louis. I love it.

Xmcdog · 08-25-2021, 03:41 AM

Quote:

Originally Posted by big willie

I am a certified commercial a/c tech. I know the the text book police will go crazy. If I can’t find a leak I use an adaptor and my air compressor with clean dry air. Charge the system with air. Everything shut off. You will find the leak. The sealers mentioned do work. Pull a minimum 300 micron vacuum before recharging. I live near St Louis. I love it.

Why use compressed air? How do you dry it? Use the recommended nitrogen. It is dry. And I can get much higher pressures that is needed to pressure test a system. The max pressure you will get is 100 psi or so.

I agree with the problems of leak checking a coach. The long hoses that are run throughout the length of it. A combine is much the same and usually covered in several inches of straw and dust.