Ford V10 A/C shuts off under load - is that a vacuum leak?

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
O

oldryder

Well-known member
Joined
Nov 8, 2017
Posts
543
Location
Avon MN
Ford V10.  On long grades before it downshifts the A/C will stop blowing out the vents.  As far as I can tell it's not diverting to the floor but it might be going to defrost.  As soon as the load on the engine drops off it come back to the dash vents.  A/C works fine except for this.

Is this likely a vacuum leak? If yes where to start looking? (that engine has lots and lots of rubber hoses)

thx to anyone taking the time to offer advice.

mark in MN
 
It's normal... The vacuum level drops under load closing the duct directional door. Installing a larger vacuum reservoir can help, as does an aftermarket vacuum pump.
 
Modern engine management can shed the load from the a/c compressor when the horsepower demand gets high or coolant temperature climbs excessively.  Nothing as crude as simple vacuum monitoring these days; the ECM has a bunch of sensor data to tell it what is happening and controls to actively adjust.  I don't know the specifics of the Ford ECM programming, but would bet it is simply managing horsepower demand by shutting of the a/c compressor.  I know the GM computers can do that.
 
If it is, and you don't want to completely  disassemble  the entire front end of the vehicle, there are numerous you tube videos for relocating the vaccuum reservoir  to under the dash. That will fix the problem. They are prone to cracking and leaking. Also, the vacuum  check valve might be  leaking. I would check that first.
 
thx for responses.  It is a Ford E450 chassis.  I will check vac reservior for leaks.  Wasn't really a problem just want to know if it's working correctly.

mark in MN
 
You're  welcome. They never go completely out until you're  in the middle of th Mohave desert. That's  what happened to me.
 
Gary's correct, most modern engine management systems will disengage the compressor if/when the gas peddle is at or near the floor to help gain a little more power, but they don't usually (that I know of) shut off the blower fan. Also if it diverts to defrost mode then it's most likely vacuum related.
 
The engine management system could shut off the compressor but it has nothing to do with the air flow diverting. Your E450 chassis has a vacuum reservoir to help eliminate low vacuum problems. Check closely for small vacuum leaks or a bad vacuum check valve. If all else fails, there are aftermarket vacuum pumps that will eliminate your problem.

Richard
 
You must log in or register to reply here.

Latest posts

Members online

Total: 1,118 (members: 12, guests: 1,106)

Forum statistics

Threads
131,972
Posts
1,388,446
Members
137,721
Latest member
Dmac3003
Back
Top Bottom