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chacho · 12-11-2013, 06:55 PM

We own a 2003 CONDOR B-plus by R-Vision on a Ford E-450 chassis with the V-10 engine. We are very pleased with the engine performance and with the overall floor plan of the unit. My question is why do we loose AC air from the dash vents every time we come to an incline on the road. As soon as we return to level road the AC air returns through the dash vents again. I have been told that there is a vacuum leak some where in the engine compartment. Aside from a vacuum leak, is there any kind of vacuum booster pump that just may not be working properly? The engine has 43,783 miles and runs great with plenty of power, even while pulling our Wrangler jeep. Any advise on what to check will be greatly appreciated.

toneumanns · 12-11-2013, 07:00 PM

Quote:

Originally Posted by chacho

We own a 2003 CONDOR B-plus by R-Vision on a Ford E-450 chassis with the V-10 engine. We are very pleased with the engine performance and with the overall floor plan of the unit. My question is why do we loose AC air from the dash vents every time we come to an incline on the road. As soon as we return to level road the AC air returns through the dash vents again. I have been told that there is a vacuum leak some where in the engine compartment. Aside from a vacuum leak, is there any kind of vacuum booster pump that just may not be working properly? The engine has 43,783 miles and runs great with plenty of power, even while pulling our Wrangler jeep. Any advise on what to check will be greatly appreciated.

I had the same problem. Seems rodents had chewed small holes in the vacuum line. Ford fixed mine so I'm not sure the line was located.

mothgrey · 12-11-2013, 08:39 PM

There is a loss of vacuum somewhere. Can be in a vacuum line somewhere. A mechanic can find it. If it's not a line then it can also be in a crack in a head or intake and vacuum is escaping when it's under torque. I have a dodge ram that does the same thing. It's in the head on that one. Since it's a 1999 I just drive it.

mus289 · 12-11-2013, 10:34 PM

Another vote for vacuum leak somewhere. I searched off and on for a month on my Damon before locating the culprit. A previous owner/mechanic had "fixed" a leak in one of the hard plastic vacuum lines in the engine compartment by running it through a piece of rubber vacuum hose. Looked perfect except the rubber hose was slightly too big and vacuum leaked around the sides of the original plastic tubing. Check all connections to ensure they are tight fitting and hoses/tubes are not cracked. Good Luck, it may try your patience a bit!

chboone · 12-12-2013, 12:35 AM

Vacuum leak. Loss of vacuum causes dampeners to fail to the defrost position. Next time it stops blowing out the dash check the defrost vents.

Chuck

NeilV · 12-12-2013, 03:11 AM

Depends on the incline. At a certain point of engine load the compressor should turn off especailly when the engine downshifts or engine load gets somewhere past 96% or so. It could alse be a vacuum leak tripping the cutout early.

mothgrey · 12-12-2013, 04:07 AM

this could help
Poor Man's Vacuum Leak Detector - Car Talk

chboone · 12-12-2013, 07:19 PM

Quote:

Originally Posted by NeilV

Depends on the incline. At a certain point of engine load the compressor should turn off especailly when the engine downshifts or engine load gets somewhere past 96% or so. It could alse be a vacuum leak tripping the cutout early.

That doesn't shut off the blower or stop the air from coming out the dash vents, only disengages the compressor clutch.

Chuck

BFlinn181 · 12-12-2013, 08:55 PM

Another way to find the leak is to spray Carb Cleaner on the vacuum lines as the engine is running. A vacuum leak will suck the cleaner into the intake and the RPM will go up. After repairing leak, you also might want to take a trip to a junk yard and pick up a vacuum reservoir. Adding capacity to your vacuum will help insure your heat/defrost flaps stay where you want them on grades.

chacho · 12-12-2013, 10:29 PM

Thanks to all who took the time to suggest how to possibly find a vacuum leak. I will try to use the information given and hopefully I will be able to located the leak. Thanks again to all.

wa8yxm · 12-13-2013, 07:14 AM

Though you can buy vacuum pumps, there should not be any boosters on that engine. They are not needed.

You can also buy a vacuum tank (NAPA sells one) but again with that engine you should not need it.

You should, however, find the leak and fix it, There are three reasons for this.

1: IT is annoying you (Biggest one right now)
2: If it gets worse it can, depending on where it is leaking, affect engine performance
3: And engine life.

jamesrxx951 · 12-13-2013, 06:19 PM

Quote:

Originally Posted by NeilV

Depends on the incline. At a certain point of engine load the compressor should turn off especailly when the engine downshifts or engine load gets somewhere past 96% or so. It could alse be a vacuum leak tripping the cutout early.

Quote:

Originally Posted by chboone

That doesn't shut off the blower or stop the air from coming out the dash vents, only disengages the compressor clutch.

Chuck

Chboone is correct. The PCM controls the A/C clutch relay. It will shut off the compressor when the gas pedal is at a certain percent. It does not affect the blower motor or vent positions though.