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Access to Dash A/C Evaporator?


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New here on Monacoars forum,  I'm very impressed with the activity and all the help/knowledge that is shared here.  Have owned the Coach about 1.5 years.  It is a pretty well maintained 2002 Monaco Signature 40'.   Last summer traveling the dash A/C worked very well.  Not so this summer.  Took it to an A/C place and they changed a leaking fitting on the high pressure hose at the compressor, still showed a small leak finally added oil and dye, ran the system, it produced very cold air during the 30 minute ride back home.  Later in the day, there is a puddle of oil at the top of the steps coming from under the Passenger side front corner of the center console.   So it would appear that the evaporator or a line has a leak.   i have removed the center console looking for the evaporator. Now I'm a bit confused.  Is the heater core and the evaporator in the same box?   I am having trouble figuring out how to get the cover off that box as it is sitting in a heaver steel tray and it doesn't appear to have room to lift it up out and over the lip of the tray.  

The oil is dripping from a couple inches to the right of the right side of the box from under some heavy rubbery/sticky tape that appears to be insulation tape.   Is that where the A/C plumbing comes into the evaporator?   Also still trying to figure out how to remove the vinyl covered panel to the right of the center console.  I have it loose at the floor but it seems to be firmly attached to the dash molding above it with fasteners that I can't see how to reach. 

Any help/advise on how this all comes apart would be appreciated very much.   I have found some threads on the dash air but so far have not found detail about how all this comes apart or exactly where the evaporator is.

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On our 00 Sig there is nothing to see on the outside firewall. I never had to open the HVAC box yet but had a leak similar to what you describe. Under the sticky rubbery stuff is an expansion valve and that's where my leak was. Tightening it did not help, had to replace it. To lift the passenger side dash, I had to remove door trim, step assist handle and bunch screws.

Re-posting my picture from a past thread for reference

image.thumb.png.4741f1f5041b03e76e47428f6525a7f6.png

Edited by Ivan K
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Thanks that was very helpful!

Got to the expansion valve and that is what is leaking,  I can't tell yet where it is leaking.   The hardest part so far is taking the bottom panel of the dash off.  Ivan yours looks like it has screws from the front that you can get at.  My screws come up from the bottom through the mating fiberglass flanges.  Had to have been installed before the full width dash was put in place.  I got it off but had to cut one screw with a body saw.  Not sure how I'll get it back on but I'll figure out something.   Now to find exactly where the leak is on the valve or fittings.   Is that a standard kind of valve or something special?   I have little to no experience with A/C.   Anybody have a part number?    

DAAF5C7B-F4B7-493E-8C4F-652B9E2BB69B_1_102_o.jpeg

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Gerald, the part number should be engraved on the valve. Mine was Eaton 329-412 and I used a cross-reference to find an identical part elsewhere. It appears that the site I bought it from does not exist anymore but attached for comparison and part cross-reference, check the port sizes, likely 1 1/2 ton capacity like ours. There is a recent post about similar system if you want to search for it.

 

image.thumb.png.4e4e36e3ce8107e3974216431697188f.png

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Gerald, you have to evacuate the system of the refrigerant via a recovery process before removing the expansion valve. You'll need an A/C shop to capture the refrigerant rather than just losing it into the atmosphere. YouTube then tells you how to evacuate the system of moisture and recharge the system which you can do yourself with a vacuum pump and a manifold gauge set which you can borrow from AutoZone via their Tool Loaner Program (you buy them and then they refund you the total amount when you return them).

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I cleaned it up, then ran the a/c for 1/2 hour to check for leaks with the UV flashlight temperature at the vents went down to 39F.  Saw no leaks, sprayed soapy water all around,  no bubbles.   So why did it stop leaking??   Seal was dried out? now with the oil started sealing again?  Hmmm.

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17 hours ago, Ivan K said:

Gerald, the part number should be engraved on the valve. Mine was Eaton 329-412 and I used a cross-reference to find an identical part elsewhere. It appears that the site I bought it from does not exist anymore but attached for comparison and part cross-reference, check the port sizes, likely 1 1/2 ton capacity like ours. There is a recent post about similar system if you want to search for it.

 

image.thumb.png.4e4e36e3ce8107e3974216431697188f.png

You can read about my issues here https://www.monacoers.org/topic/4400-ac-dryer-tank/?do=getNewComment

My expansion valve was leaking also. First I just chanced the o rings and that stopped it. Then i discovered I had leaking hoses back by the compressor. I ended up replacing about 4 foot on both hoses. I can't find any more leaks but still can't get my pressures to read correct. 

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  • 2 months later...
On 6/18/2022 at 7:46 PM, vito.a said:

I replaced our dryer and expansion valve.  Pictures show the part numbers.  Both were common big truck parts and inexpensive.  

Dryer part number.jpg

Egelhof expansion valve 1.jpg

Expansion valve end.jpg

Vito,
I ordered the filter/dryer and installed it.
I just now ordered the expansion valve. I will install it next time the dash AC needs service.
Thank you so much for the part numbers.

Lee Smith

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