Dash AC Beware

[ValleyCenter]

I purchased my motorhome, 2001 dolphin, Ford V-10, a few years ago from a private party. from the beginning the AC never really got cold enough. I had freon added, leak tests, heater valve checked, and nothing ever really help it much. I started playing with it a week ago, ran some tests of my own and found the heater hoses were not installed correctly. the hose ran directly from engine pump to heater core then to the heater valve and from there returned to engine. The correct plumbing should be from engine pump to valve then heater core and then return to engine. My heater core was consantly getting hot water thus was warming the air even when the AC was running. I finally fixed it and routed hoses correctly and now I'm getting 45 degree air, 65-70 degree before. You might want to check your heater hoses and verify the correct plumbing. Hard for me to believe that factory did this but I'm not sure.

[Ray,IN]

Sounds like a shade tree mechanic switched the routing. I once had a pickup that acted like that. I discovered the heater valve was faulty and allowed flow when it was "off".

[kennersonf]

A couple of years ago I had to replace my heater control valve. When I did it, I found out that National had installed the old one backwards. We bought the motorhome new, so I know a mechanic didn't do it.

[Midniteoyl]

Dunno... lotta cars have the valve on the output now...but there also should be an 'air mixer' door..

[donhoward49]

My dash AC also is Too warm, just barley turning the control gets it warm.. But i am wondering also,, if the shutoff is past the heater coil would that not shut off the water?? and stop warm water from getting to the coil.
I am not doubting what worked for you, just tiring to understand the correct "fix" for me.
I wonder if my control is letting some water through, when it should not.. Any ideas?

[ValleyCenter]

my valve was working fine. when ac was on the hose on the outlet side was cool to touch and inlet side was warm or hot. I had also removed the valve and check it manually and it worked fine. easy to do. If hot water had been leaking through the valve both inlet and outlet hoses would have been hot or warm. As for the hose to heatercore from pump it was always hot even with the valve turned off. I let the engine cool down completely. checked temp of all hoses by hand. turned on ac then started engine. let it get up to about 180 degree and went and felt the hoses. Hose going from engine pump to heater core was hot, hose going from heater core to valve was hot. hose returning from valve to engine was cool. 1) the hot temp on hoses from pump to heater core and heater core to valve tell me heat was making its way into heater core. granted it was not flowing but heat was making its way there. 2) the outlet side of the valve hose was cool which re-confirm the valve was working fine. This is the logic I used to diganose. In any event, the system is now plumbed as I described in my first comment and it is now blowing air at 45-50 degree.

[Billieg]

Quote:

Originally Posted by Midniteoyl Dunno... lotta cars have the valve on the output now...but there also should be an 'air mixer' door..

The Ford PU's have a problem with that door. Mine does and the door costs $56 but the labor to replace it costs $645! I just put in a shut off valve and it works fine.

Thanks for the org. post. I know a lot of people will benefit from it!

[Ramblin]

This is at least the second time I've read about this exact same issue. My 2002 Dolphin 6356 has poor dash air. I wonder if mine is backwards too.

[georgem37303]

You all might want to check to make sure the heater box is securely fastened to the fire wall. Mine only had 2 screws holding it and it came loose and warm air came in from around it causing the air to be a little warm. I had the repair shop caulk the edges and add screws to it.

[sleeper212]

As a rv tech I have fix several National rvs with the heater hoses hooked up backwards staight from the factory. It is the first thing I check if the dash ac is not cooling enough. The next thing I check is the bypass valve. I have seen them stop working within 6 months.

[Billieg]

Quote:

Originally Posted by sleeper212 As a rv tech I have fix several National rvs with the heater hoses hooked up backwards staight from the factory. It is the first thing I check if the dash ac is not cooling enough. The next thing I check is the bypass valve. I have seen them stop working within 6 months.

I went to Lowes and bought a brass lever ball joint valve 3/4" and 2 barb ends 5/8 to fix mine. Total cost was $22 and it's built like a tank and should never wear out unlike the $59 plastic bypass valve that was in there...

[rvgrandma]

We had our a/c fixed then they discovered the automatic valve to switch hot water off was shot. Options: new automatic at a few hundred or a manual - we opted for the manual. It means we have to get out, open hood and switch but the cost less than an automatic switch.

[legryz]

I had the same problem with my 2002 Dolphin (bought used in 2006). The dealer told me that none of the dash ac 's worked that good, just run the gen. and the roof top air. After a 2006 summer trip out to Arizona (very, very hot) I decided to take a look at it myself and found the same problem, hoses connected wrong. I also replaced the control valve, just in case the old one was bad. Since than I have had very cold dash air and it makes driving so much more enjoyable.