Dash Air Problem

[Pete & Linda]

When I stop in traffic after a short time I get hot air out of the vents, going down the road good cold air. Any ideas?

[oemtech]

You are getting hot engine air as your A/C intake is open to the engine bay. This goes away after you reach highway speed. Run on MAX AIR and then you only use the air inside the coach.



One other item to check is the heater control valve. If you have an Evan's system this valve does not alwasys close and allows some hot water thru to the heater core.

[DriVer]

Quote:

Originally Posted by Pete & Linda When I stop in traffic after a short time I get hot air out of the vents, going down the road good cold air. Any ideas?

When you are in stop and go traffic, your AC control should be on Maximum or Recirculate. Bringing in hot outside air (engine compartment) at a stand still will render your AC system ineffective if it is in AC Normal Mode.

[tomgagne]

Although I don't have the same coach I had a simillar problem and it was a faulty electric fan on the AC heat exchanger (AC radiator). Drive/move and there is enough air flowing through the radiator, slow down/stop there isn't enough air, then AC warms up. Just a thought.

[KSDP]

You guys are amazing. I had the same thing happen last night while waiting for traffic to clear so I could back in the driveway. Look like i have the answer and I didn't even have to ask the question.

[Pete & Linda]

Thanks Mike and oemtech I will try the max/recirculate. What are the two electric fans for in front of the radiator for. The AC or additional cooling or both? When I was going down the road the other day (103 degrees) I could hear them cycle but when I was stopped and the AC was blowing hot air they were not running.

[DriVer]

Quote:

Originally Posted by Pete & Linda Thanks Mike and oemtech I will try the max/recirculate. What are the two electric fans for in front of the radiator for. The AC or additional cooling or both? When I was going down the road the other day (103 degrees) I could hear them cycle but when I was stopped and the AC was blowing hot air they were not running.

Pete & Linda, Those are called auxiliary cooling fans and they can spin-up at any time. They may or may not work when you expect them to because they are controlled by the ECM computer.

The sound that you hear under the hood while going down the road is the main clutch fan. You can not often hear those electric fans very well when your engine is making revs. The aux fans do not provide a lot of cooling potential but should be running when you are not moving if the coolant temperature triggers the ECM to call for them to come on.

To test the fan circuit, start the engine from cold, the fans should spin up and within a few minutes shut down.

[max49]

Quote:

Originally Posted by Pete & Linda When I stop in traffic after a short time I get hot air out of the vents, going down the road good cold air. Any ideas?

Mine works the exact same way and always has since new, and I always use the "Max" cool position. If I'm in stop & go traffic, I just have to turn it off til I can maintain 30/35 M PH. I took it in when it was under warranty. They told me it was working as designed and 'it is what it is'. Now I'm just glad it cools when we are moving.

[HMXDave]

On my 2000 P32 TripleE Embassy we had a similar problem....plus it would also stop blowing out of the vents in the dash and start going elsewhere. My mechanic said there was insufficient vacuum reservoir (or maybe there wasn't one?) so when the engine vacuum was weak, the cooling system tended to do whatever it wanted....which was turn the heat on. Anyways....he added a vacuum reservoir and never another problem.

[oemtech]

Quote:

Originally Posted by HMXDave On my 2000 P32 TripleE Embassy we had a similar problem....plus it would also stop blowing out of the vents in the dash and start going elsewhere. My mechanic said there was insufficient vacuum reservoir (or maybe there wasn't one?) so when the engine vacuum was weak, the cooling system tended to do whatever it wanted....which was turn the heat on. Anyways....he added a vacuum reservoir and never another problem.

Like this one... standard part of my 2004 Newmar.