The Chrysler Minivan Fan Club Forums banner
1 - 7 of 7 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
So a couple of questions that I believe are related. Got this 2010 T&C in the summer time 4.0L I'm expecting to get 16-17ish mpg city and 25ish highway. The main thing I'm concerned about is the mileage. After purchasing the van I noticed that the mileage was 24.8 mpg on the way home (all hwy) calculated by the computer. Then in town I see I'm getting 11.8 - 12.5. What? Is it really that terrible? So after a couple of tanks of gas, I realize it is that terrible and I start reading about why and I try a few things:

  • Turned off the ESP, no difference.
  • Turned off ECON shifting, better pickup driving, no difference in mileage.
  • Turned off A/C, Now getting 17mpg in the city.
After this find, I started to investigate the A/C more closely. I realized that the compressor is running ALL THE TIME. It never cycles off. I found this strange as every other vehicle I've owned, the A/C compress will cycle off and on as it builds pressure then evaporates and condenses. However, I've also never owned a vehicle this new. So...

Should the A/C Compressor be running ALL THE TIME?

If not, what sensors should I be looking at? I'd rather do the work myself, but am not opposed to taking it to a shop.
 

·
Registered
2007 T&C Touring 3.8L 230k+ mi
Joined
·
222 Posts
First thing I would do is borrow an ac manifold gauge set from a parts store, they loan them for free. Hook up the gauges (be sure the valves are untwisted before connecting them to the high and low ports) and measure + note the pressures when the van is off and also when the ac is on, fans full blast

take care to untwist the valves again before removing them from the ports, don’t wanna get frostbite on your fingers

Too much or too little refrigerant in the system can cause the ac compressor to stay on all the time, and the pressure readings you measure can help you and us figure out which it is and go from there
 

·
Super Moderator
Joined
·
30,166 Posts
Automatic Temperature control?
System not running efficiently, such as:
  • low refrigerant
  • dirty condensor?
If the system is working harder than normal to maintain a set temperature, there's a reason.
 
  • Like
Reactions: dlukowsk

·
Registered
538 RWHP, LS motor, RX7 body
Joined
·
583 Posts
12 mpg is not out of the realms of reality, depending on your throttle habits. 24 highway is great.

Compressor not cycling could be a function of ambient climate. What's the temperature outside, and are you idling when observing this.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #6 ·
12 mpg is not out of the realms of reality, depending on your throttle habits. 24 highway is great.

Compressor not cycling could be a function of ambient climate. What's the temperature outside, and are you idling when observing this.
It's been in the 90's out and yes I've been idling. 5mpg just seems excessive for A/C draw.
 

·
Loveably weird
Joined
·
456 Posts
You don't have your vents set on defrost, do you? If they are on defrost the AC will be on all the time to help dehumidify the air hitting the windshield, so it doesn't fog over. At least I know this to be the case on the Trailblazer's my wife and I own.
 
1 - 7 of 7 Posts
Top