Dash Air Conditioning problem

[Walter Parr]

I have a 93 Grand Marquis that has an AC leak. It has been converted from R-12.
The shop found a couple of leak areas and fixed them, but is still leaking. They did a dye test but can't find it, saying the 2 hoses aren't accessible to find a leak.
They said it would be hard to run new hoses because the frame isn't accessible in places because of how the body goes over the frame.
They said the parts to run new hoses with fittings would run around $700 and the labor about $2,000 or so (based on the last job the did on a 40" DP with a CAT)

Any ideas on what to do / way to go?
How hard would it be to run the hoses myself, and how would I run them?
How about using stop leak & conditioner? (they said it could mess up the compressor) If so how much?

[Fred Brooks]

Greetings Walter,
  The issue I had on my 2000 Marquis was the hoses were "blistering" internally on the inside liner of the hose from the compressor to about six feet of hose going into the frame rail. I ran new high & low pressure hoses up over the rear suspension then along the belly pan on the drivers side until I got to the generator where I could go up behind it then past the propane tank and up and over the front suspension. I also replaced the condenser with the new serpentine style hi efficiency cross flow style. Also change your reciever dryer and flush the expansion valve. I jacked up my coach as high as I could using the leveling jacks, then cut 4 by 6 blocks to wedge between the frame and the ground front and rear. I also used electrical conduit clamps to secure the hoses to the belly pan where ever I could make a secure mount. Take your time and make a project out of it. It took me 6 hours just to run the hoses and clamp them in place. If you don't want to tackle the job, Pirtek may do it. (they do hydralic repairs on location)
Hope this helps, Fred Brooks

[Gerald Farris]

Walter,
It is not common for the hose to be leaking in the middle of a run, but hose leaks are usually at the splice where the metal connector is attached to the hose. However, anything is possible on a 25 year old hose, but I would not replace a hose when I could not find something wrong with it. The evaporator core or compressor are normally the most leak prone areas of your dash A/C.

You have not said how much refrigerant your coach is leaking. If a dash A/C unit leaks less than 2 cans (1.5 lbs.) a year, I do not waste my time looking for the leak. I just service the system and top it off every spring. At $5 a can for refrigerant, I have more pressing things to fix. Remember that R 134A has a smaller molecular structure than R 12, and therefore it is more leak prone unless you have a very tight system.   

Gerald

[Walter Parr]

It leaks fast enough that they charged it Thursday, I drove it home Sunday and did have AC to make a less than an hour drive.
How do you test the compressor?

[Walter Parr]

Greetings Walter,
  The issue I had on my 2000 Marquis was the hoses were "blistering" internally on the inside liner of the hose from the compressor to about six feet of hose going into the frame rail. I ran new high & low pressure hoses up over the rear suspension then along the belly pan on the drivers side until I got to the generator where I could go up behind it then past the propane tank and up and over the front suspension. I also replaced the condenser with the new serpentine style hi efficiency cross flow style. Also change your reciever dryer and flush the expansion valve. I jacked up my coach as high as I could using the leveling jacks, then cut 4 by 6 blocks to wedge between the frame and the ground front and rear. I also used electrical conduit clamps to secure the hoses to the belly pan where ever I could make a secure mount. Take your time and make a project out of it. It took me 6 hours just to run the hoses and clamp them in place. If you don't want to tackle the job, Pirtek may do it. (they do hydralic repairs on location)
Hope this helps, Fred Brooks

How did you determine the fault with the hoses?
I don't mind doing the work,  though I don't have my hydraulic levelers functioning at the moment.
Home much did your hoses run you?

[Gerald Farris]

Walter,
Before you start throwing expensive parts at your problem, and therefore wasting money and time, you need to determine the problem. There are 3 ways to locate a refrigerant leak. The first is good old soap and water, but it only works were the system components are in the open and accessible which is not your case. The next is U/V dye and a black light, but this system can be hampered by accessibility also. However, it usually works with patience, and experience. The last is an electronic refrigerant leak detector. Since it detects refrigerant in the air, you can find leaks in areas were you can not see like the evaporator core or your hoses running above your basement. Electronic leak detectors run from about $30 to $300 for professional models, but you can get a pretty good one here for a little investment; https://www.amazon.com/LotFancy-Refrigerant-Detector-Halogen-Condition/dp/B00P90BKOG/ref=as_at?creativeASIN=B00P90BKOG&imprToken=zHpT1z1t9fCEVQAc3ysnqA&slotNum=4&ie=UTF8&linkCode=sl1&tag=traininghvac-20&linkId=1ac77761d957e5b2662f08eeeeb078cf

Gerald
     

[Mike Shumack]

It leaks fast enough that they charged it Thursday, I drove it home Sunday and did have AC to make a less than an hour drive.
How do you test the compressor?

The good news is that the faster it leaks (the bigger the leak) the easier it is to find.
Like Gerald said, you can use a dye or a "sniffer" to find leaks. If the last guy that filled your AC put a dye in, you may already be able to find the leak without adding more refrigerant. Most of the over-the-counter AC charge cans usually contain a dye that is visible to the eye (professional shops generally use the dye that is only visible with ultraviolet light since it is easier to locate small leaks).

On the compressor, look around the pulley (backside where shaft comes out of compressor body (where the seal is located)). Is it oily? Look around the places where one component connects to another (like a hose to compressor or hose to condenser, and where the hose ends metal fittings are crimped on). Signs of oily residue usually indicate a leak. also check the gauge/charging ports (Schrader valves) to see if they are oily (are the dust caps in place?). The schrader valves are the same design as what's in your tires - they can leak or get loose too.

I can't remember ever finding a bad hose (a leak in the rubber part, unless something rubbed through it). Leaks are usually at a point where two components are fitted together, or a cracked weld or pin hole in a condenser or evaporator, or at a seal.

I recall back in the 90's when the shop I worked in was doing a lot of R12 to R134 conversions, we were also changing the rubber hoses too because some of the older hoses would leak R134 "through the rubber" as the 134 molecule is much smaller than R12 (as Gerald mentioned). The new hoses were called "barrier hoses". I don't recall what year your coach is but this should not be an issue for coaches  built in 2000+). However if this was happening on your coach it would be a very slow leak (and you would see signs of the leakage on the hose - assuming you can see that section of hose).

Good luck

[Walter Parr]

The shop said they did the dye test, soap test, a pressure test & even used nitrogen??
If a shop can't find it (unless they AC guy is incompetent)?
It's a 93, but don't know when the R12 to R134 conversion was done.

I don't mind spending money to get it working (too hot driving without AC) but don't want to waste money, have had it in the shop twice without any results.

I initially bought a fill can and it wouldn't put any freon into the system, tried the same can on my truck and it was charging it, went back to the Coach and no luck.

For a temp work around, like going to the Farmington Rally, can I run the generator and the roof ACs while going down the road? Then maybe I can pay someone to help me, see what I'm doing wrong?

[Mike Shumack]

Walter, if the refrigerant is leaking out in just a couple of days - then the leak is pretty big. It could be that shop cant access the lines where the leak is (somewhere along the frame/underside) or perhaps the shop is just not interested in fixing your coach (warning - some shops that don't want to do a job will just quote customer a "high" price tag to fix to run them off, so don't go with your first shop/price. Get a second shop to take a look).

Do you have the Owner's manuals and schematics for this coach. I found some on the Beaver Coach Assist site.
https://get.google.com/albumarchive/115658612666054584440?source=pwa

Other than the 80 feet of AC hose running back to front, the rest of the system is the same as on any car/truck of that age. I don't know how accessible your frame is (a 93 Marquis) bu ton my '05 it's pretty hard to run anything from to back, but it is doable . Can you access/see the frame rails from inside the basement compartments?

These drawings are on the site linked to above (says it is correct for 93-94) color/text added by me:

[Steve Huber Co-Admin]

Walter,
You can run your roof ACs while driving (running generator). In the summer, the dash air will not cool the coach so the roof ACs are needed in any case. If you couldn't get the system to take any Freon, how did the service shop introduce dye, etc. into the system (or did they)?
Steve

[Mike Shumack]

Steve, I suspect the refrigerant charge is so low now that the compressor clutch won't engage to draw in the refrigerant from Walter's can.  A shop would know how to jumper the compressor clutch switch or they may have a "charging station".

I still don't understand why shop says they can't find a leak... but the issue will soon become whether or not there is enough oil in the system for it to operate property and last.

Oil that is lost through leakage can't be measured so you don't know how much to add. You can add some oil back in (oil charge) with the refrigerant, but too much oil in the system affects cooling ability and too little oil can result in compressor failure down the road. It may be better to have shop remove the evaporator and condenser and drain and add the correct amount of oil, drain/fill compressor, and replace the Dryer as part of this repair.

[Fred Brooks]

Hi Walter, On my coach the issue was not a leak, it was excessive high pressure on the high pressure hose and low pressure on the low pressure hose. This means you have a restriction in the system. In my case the blistered pieces migrated to the condenser and plugged it up. A technician at WW Williams advised me that Safari Coach was using hoses in around 2000 that were prone to blistering after 12 years. We cut off a 6 foot piece and split it lengthwise and there was chunks missing. Your issue Walt is a pretty big leak. It seems to me connecting  a nitrogen source to your gauges feeding the system on the high & low side you should be able to hear where the leak is or at least push more dye out.

I drove my coach for a year without any dash air, I ran the generator and house air conditioner with some fans positioned just right so my "honey" stayed cool until I got it fixed.
Fred Brooks

[Mike Tomas]

This all sounds vaguely familiar as my 2000 Patriot thunder also has no working dash AC. I too run the generator and both 13.5Kbtu roof units to help cool the coach in the hot Arizona sun. Is it worth it?     27Kbtu doesn't quite do the job out here.   

But it's not high enough on my repair list to take a look at fixing just yet. Actually I'm considering going ape-ish and replacing the dash system with something like an underbelly or small Thermo King X-series or TK-Cool, or SLR Series something with hybrid PTO, AC & DC power options  .

-HEY! I live in Arizona. I want a Meat Locker!  8-)

[Mike Shumack]

There are companies that make AC Kits for cars/trucks that did not come with AC (classic cars, etc.). Maybe one of these kits would work for you.

However, if your going to use an engine driven AC Compressor, then you still have to get the hoses from the back of coach to the front. And the other challenge would be fitting in the "universal" evaporator and duct work. Since our coaches already have this equipment in place, I think it would be easier to just replace what is there with the same parts.

This is one company that makes high-quality AC Kits that I am aware of. https://www.vintageair.com/builder-series/?subcat1=Under%20Dash

Now if you wanted to run an "electric" AC compressor you could install everything up front. https://www.seanhylandmotorsport.com/blog/12-v-air-conditioning-compressor-how-can-you-decide-if-one-is-right-for-you/

[Mike Tomas]

Thanks Mike!

Really, I'm just attempting to elicit thoughts outside a box. And you did it! But those options I suggested are on the table including your suggestions above. I am an integrator. So adaption isn't really much of an issue to me. But when I get around to fixing the Dash AC (not likely anytime soon), I'll seriously consider all options including fixing the installed system.  Right now, the fan is nicely blowing in my face. But BTUs man! It's all about BTUs. I'll likely upgrade the front AC unit with a 15.5K BTU (or whatever will fit that's higher) for the rooftop AC before I get the dash running. Right now, i'm more interested in getting additional 'must haves' than spending money on the dash AC. maybe even an Insta-Pot.