Air conditioning service

The workout of the R134a compressors in south states are more brutal in hot temperature and humid. The refrigerant oil in modern compressors doesn't have oil sumps, are critical to the extremely temperature and pressure cuz the R134a refrigerant can't pick up the oil to circulating the system (lubricate compressor). Results: seized and noises.

I've noticed the R134a compressors in diesel powered vehicles are no problem cuz of low RPM engines and longest A/C clutch cycling (Off/On cycling) operation. I never replace seized compressor in a diesel powered vehicle.
 
Wirelessly posted (sent from a smartphone. )

I noticed that when I rev the engine a little higher the a/c gets colder. I suspect that is the sign freon is running out.
 
sequoias said:
Wirelessly posted (sent from a smartphone. )

I noticed that when I rev the engine a little higher the a/c gets colder. I suspect that is the sign freon is running out.
Click to expand...

Right, low freon in system. Likely to have no cold air in few months.
 
Last Thursday, I took my mother's 2002 Buick Century w/ 54K miles on it, for a long trip check up, changed oil/filter, service automatic tranny (changed filter/ATF),and rotated tires. I check A/C operation, sound very good (Has not been A/C service since brand new), vent abt 42 degree F and outside temp 92 degree F in O.C. in Calif. Then I took my mother with me in her car, headed to Tucson, AZ, arrived Friday morning for a funeral service of my cousin. I am okay.
I notice the blowing too long to get cold air when start-up the engine. I can see why the freon is getting degrade chemical in freon when the air temp about 105 degree F in Tucson. On evening day, the A/C starts to blowing cold air after normal start-up. Time to service A/C system in someday when return to Ca.
PS.. I didn't hook up the A/C service machine to the system to check Lo/Hi pressure gauges, I just feel the low side pipe, very ice cold with my hand.
 
Today I took my 2006 Jeep Commander in for A/C. It is cold, but not before driving about 5 miles after starting. Mechanic said freon was not down enough to cause the problem. Also the readings on the machine were slightly elevated by 10 lbs?

He ordered 2 expansion valves. One for front and one for rear A/C. I didn't know the rear controls had their own unit hidden near the wheel well. :shock: Probably will be more expensive to repair. It was 98 degrees with heat index of 105.
 
TinCanSailor said:
Today I took my 2006 Jeep Commander in for A/C. It is cold, but not before driving about 5 miles after starting. Mechanic said freon was not down enough to cause the problem. Also the readings on the machine were slightly elevated by 10 lbs?

He ordered 2 expansion valves. One for front and one for rear A/C. I didn't know the rear controls had their own unit hidden near the wheel well. :shock: Probably will be more expensive to repair. It was 98 degrees with heat index of 105.
Click to expand...

I think the Lo/Hi pressure reading rise 10 PSI (not lbs), is like to be cause overcharged ( too much freon in the system) or restrict airflow cross condenser.

2 expansion valves? If the high side pressure shows low pressure and low side pressure shows high pressure that would be expansion valve problem.
Mechanics are judging to determine what's cause.... tricky and make mistakes.

The expansion valve in the rear, is easy fix. The TXV (stand for expansion valve) is mounted under the cargo floor behind the rear tire well. About half hour to remove and reinstall new TXV (add time for recover, evac & recharge). Labor time for front and rear TXV replacement is about 2 1/2 hour.
 
deafsmogtech said:
I think the Lo/Hi pressure reading rise 10 PSI (not lbs), is like to be cause overcharged ( too much freon in the system) or restrict airflow cross condenser.

2 expansion valves? If the high side pressure shows low pressure and low side pressure shows high pressure that would be expansion valve problem.
Mechanics are judging to determine what's cause.... tricky and make mistakes.

The expansion valve in the rear, is easy fix. The TXV (stand for expansion valve) is mounted under the cargo floor behind the rear tire well. About half hour to remove and reinstall new TXV (add time for recover, evac & recharge). Labor time for front and rear TXV replacement is about 2 1/2 hour.
Click to expand...

I will show them your thoughts on fix. Maybe that will reduce the guessing time.
I do not have a spare tire well. The tire is under the car. The cargo floor is the 3rd row seating. It is probably under the passenger side controls and vents. Thanks for the suggestions.
 
TinCanSailor said:
I will show them your thoughts on fix. Maybe that will reduce the guessing time.
I do not have a spare tire well. The tire is under the car. The cargo floor is the 3rd row seating. It is probably under the passenger side controls and vents. Thanks for the suggestions.
Click to expand...

Oh, I see. Chrysler mini vans like Grand Caravan/Voyager/Town&Country with dual HVAC, have the TXV mounted under the cargo floor near the wheel well on driver side. Older Chrysler mini vans, the TXV mounted under the middle of the cargo floor close to the driver side. Dual AC system in any vehicles, usually have 2 TXV (expansion valve)s.
 
I recalled I install a rebuilt compressor (found no pressure in compressor) after flush the system and replaced dryer/receiver. Same pressure problem and no cold. Then I replaced a new TXV, found same pressure problem again. I can't figure out why, then I went to check the rebuilt compressor and rotate the clutch to see if there is resist rotation , found freewheel compressor, called 2nd rebuilt compressor, finally got good pressure readings and very cold air. The original pressure readings were Hi- 100psi and Lo- 65psi. With 2nd compressor Hi- 270psi and Lo- 45psi. I misdisgnose faulty TXV that is where many AC mechanics make mistakes or misdisgnose. Rebuilt or wrong compressor can be tricky. But unnecessary parts are billing to the customer.
 
Last Sunday, I drove a 2002 Buick Century (my mom's car) on 10 freeway way to Tombstone from Tucson for tour the Wild West town myself, on middle way of trip, I feel little hesitate when the car travels 70 mph, I feel I have problem with spark plug wires cuz of slight misfires. I turned AC off to see what's going on with hesitate condition. Nothing wrong, then turns AC on, continue to driving and arrive Tombstone. ( I use 91 high octane fuel for a long trip). After tour, I return to Tucson, feel hesitates again. I begin to worrying over the misfires, no CHECK ENGINE light on or flashing. Next day my mom and I head home from Tucson, feel hesitate again but minor on way to Phoenix. We enter Calif line. No more hesitates. Whew. Stop in Palm Spring for final refuel and head home safety. AC operation was doing fine when arrived home(my mom's). I told my mom I will replace spark plug wire set someday. She kiss me when I head to my home.
 
Two weeks ago I replaced a broken freon hose and refilled with 4 pounds of r134a on the truck.

Total cost: $55.

Not bad I think.
 
deafsmogtech said:
4 pounds of R134a? Silly I dont like your post, pls PM me right now
Click to expand...

Like I told you in PM. It was on a Freightliner. They require more freon than your normal car.

My point is that in your OP $85 a freon pound is expensive. I get them at the shop for $10.
 
Hmmm, I didn't notice til now. I had two diesel vehicles both has AC and I never had a problem with it, but with gasoline version I usually have to deal with issues on AC. Now that engine speed may be the factor. I can't get my truck diesel engine RPM past 4k, usually stays below 2K RPM.

deafsmogtech said:
I've noticed the R134a compressors in diesel powered vehicles are no problem cuz of low RPM engines and longest A/C clutch cycling (Off/On cycling) operation. I never replace seized compressor in a diesel powered vehicle.
Click to expand...
 
diehardbiker said:
Hmmm, I didn't notice til now. I had two diesel vehicles both has AC and I never had a problem with it, but with gasoline version I usually have to deal with issues on AC. Now that engine speed may be the factor. I can't get my truck diesel engine RPM past 4k, usually stays below 2K RPM.
Click to expand...

It's Jeep thing. I see there is a lot AC problem at the dealership. I believe Chrysler is worse than GM for AC system.

Also I always rev to 5k rpm for enter highway ramp all times and no problem with AC system for over 11 years from Subaru. But it's true low rev is better for AC system.
 
Back
Top