Monaco dash A/C

[mike408]

I have a 96 monaco dynasty. engine a\c freon has leaked out over time. I need to partially charge system for leak ck. I haven't been able to find out how much freon the system takes.
your input would be helpfull.

Mike

[MrMark52]

You don’t use refrigerant to find a leak - you use dry nitrogen.

To locate a leak, first a thorough inspection of the complete system is warranted - look for signs of oil or wet paper appearing rubber lines. Oil will seep thru leak points.

This may require accessing the heat/cool box on the coach’s firewall. It is very common for the refrigerant tubes to fail as they penetrate the endplates of the evaporator.

Since you don’t mention who built your coaches chassis, most heat/cool boxes are/were made by Evans or SCS Tempcon or DENSO - starting in ‘92-‘93 the EPA required all systems to be marked with the required charge amount, and that usually can be found on a sticker somewhere on the heat/cool box on the firewall side.
Further information about those manufacturers can be found with a little keyword searching.

FWIW - some compressors have known leak failure issues - the OEM compressor on our ‘02 coach with the 8.1l Chevy engine had a Delphi on it. That compressor had a belly o-ring seal failure issue that was hard to detect - without dye in the system, the compressor had to be removed from the system to find the leak, even a system with dye in it so depending on the severity of the failure.
So - researching the compressor on your coach is advised as well as the complete system.

Once you have located and repaired the leak - replace the filter drier. The lubricants used with R134 love moisture, and any leak that oil will migrate thru will allow moisture into the system. Moisture is bad, very bad, for refrigerant systems.
Then, evacuate the system to 1000 microns twice, confirm it will hold 1000 microns for 30 minutes, then break the vacuum with dry nitrogen.
Then a final evacuation to 500 microns, check that it holds for a minimum of 15 minutes, and break the vacuum with the recommended weighed in charge of refrigerant.

[jacwjames]

The year after we bought our rig it quit cooling.

I added one can of 134A and the compressor took off, didn't have to do anything else until last year. I bought a set of gauges and used the chart in my manual to set the pressures. NO I didn't evacuate the system but I didn't break any lines or change any parts. So far so good, still blowing cold.

[Steve911]

Here is a link to charge information from Tempcon: https://www.proairllc.com/pub/media/...%20Systems.pdf

[mike408]

thanks for the info

Mike

[RobRoy]

Originally Posted by mike408

I have a 96 monaco dynasty. engine a\c freon has leaked out over time. I need to partially charge system for leak ck. I haven't been able to find out how much freon the system takes.
your input would be helpful.

Mike

That said buy some refrigerant with dye & oil and a set of gages and add the refrigerant thu the low side and read your gages using a chart like this with the engine running @ 1200 rpm. I might suggest emptying the system and pulling it in to a vacuum first for 30 min.




That said what Mark52 said in post #2 is some pretty sage advice IMO.
300psi of dry nitrogen will show you some very hard to find slow leaks but the average DYI guy is not going to have the dry nitrogen and high and low gages to regulate it nor the sub micron gage.



ps Having no idea how the a/c hoses are routed from coach to coach and are different even from the same model depending on the options, I personally would only use gage method and pressure readings to determine if the system is filled correctly. That said the Tempcon fill specs will put you pretty dern close.

Happy Trails

[vito.a]

Most of these diesel Monaco coaches take 4 pounds of R134a. And most of them leak down over a 6-12 month time span.

[Onrecess]

Originally Posted by vito.a

Most of these diesel Monaco coaches take 4 pounds of R134a. And most of them leak down over a 6-12 month time span.

LOL, right on both counts!

[oilcan]

if it was me I would go to to any auto supply store or harbor freight and purchase a recharge kit for about 25.00 and recharge it the kit comes with everything required and instructions on use

[veraken]

I used this to recharge my AC system

https://www.walmart.com/ip/A-C-Pro-A...1?athbdg=L1100

[Dueyp]

Originally Posted by vito.a

Most of these diesel Monaco coaches take 4 pounds of R134a. And most of them leak down over a 6-12 month time span.

AGREE! I give up trying to find the leak. When I see R134A on sale it time to stock up. Got to have AC in Texas.

[imkwuzn]

Had to evacuate and recharge my system a few years ago. I elected to replace the evap/dryer and O-Rings at the time. I don’t recall the exact amount of R134a but 4lbs sounds about right. I had it done at a diesel shop as I don’t have the gauges or vac pump to do it myself.

Be careful of the AC-Pro and similar do it yourself kits as they also contain stop leak which can clog up the condenser and wreak havoc on the system. Much better to buy a cheap set of gauges and the small 1lb cans of pure 134a Freon to top off the system if needed.

[MrMark52]

Originally Posted by imkwuzn

Be careful of the AC-Pro and similar do it yourself kits as they also contain stop leak which can clog up the condenser and wreak havoc on the system. Much better to buy a cheap set of gauges and the small 1lb cans of pure 134a Freon to top off the system if needed.

X2 x 100 on any charge kit that also claims to “seal leaks”!

Not only can sealants wreak havoc on your system, the poor technician who has to service your system gets his equipment contaminated with whatever is/was in your system - and it’s a PIA if not impossible to clean everything up.

And BTW - [B] those cans you buy are not 1 lb cans - they are 12 oz. cans - last I looked, 1 lbs = 16 oz. [B] To charge 4 lbs into a system will take 4 cans, assuming you can get 4 cans into a system that has been opened (via a leak or servicing a component) without first pulling a vacuum as described previous.

If the system isn’t properly checked for leaks and properly evacuated then it’s efficiency will be reduced due to non-condensables (which means any gas other than the intended refrigerant) still in the system which will “blind” the condenser. And the vicious circle of breakdown cycles continues.

[wimpy]

Limo service for 20+ years. Lincolns primarily with E350 or E450 mini-buses. After losing money when AC goes south with clients aboard, started an annual program. We ALWAYS evacuated & captured R134a. Flushed the system with a chemical flush, replaced the accumulator & orifice tube & o-rings where hoses were opened.

We then did a 30 minute vacuum & recharged the system making sure the correct amount of oil was put in the system along with the recycled + added R134a.

ALWAYS carry a spare serpentine belt. Finding a 130" replacement on a Saturday afternoon will probably be impossible or it was in our case.