Manager Forum

I HAVE A 2005 MINI COOPER S WITH A/C NOT COOLING. REPLACED COMPRESSOR, FOR BAD COIL. ALSO REPLACED CONDENSOR, AND DRIER. PRESSURE CYCLING HIGH AND TURNING ON FAN, HIGH SIDE GOES TO 275 WHEN FAN COMES ON. WITH AIR BLOWING ACROSS CONDENSOR WITH SHOP FAN PRESSURES ARE GOOD. CAR NOT OVER HEATING, INSIDE TEMP AT 50 DEG.

What are the temps on the low side line at the inlet of the evap and the outlet of the evap core?

80/103

Those temps do not seem accurate to me, if the car is blowing 50 degrees the evap has to be a least that cold. What are measureing the temp with? I find it best to use a thermocouple on my DVOM, when useing an IR temp gun, you get lots of backround heat and it is hard to get just the a/c line temp.

if low pressure line at evap is cold then i would look into a blend door issue. a good point was made about the pressure. you stated that with the cooling fan on and the shop fan blowing across the condenser pressures are good. what happens if the shop fan isn't blowing across the condenser? if pressure spikes then the second stage of the fan probably isn't working. the issue with the coil may have resulted from the compressor overheating. the result has been repaired but not the cause. check tsb SI M 64 02 05.

WITH THE SHOP FAN NOT BLOWING THE PRESSURES SPIKE TO 275 ON THE HIGH SIDE. THE COOLING FAN OPERATES AT LOW SPEED NORMALLY, BUT AS SOON AS THE PRESSURE HITS 275 IT KICKS UP TO HIGH SPEED. I SEEM TO HAVE GOOD PRESSURE AND OPERATION AS LONG AS THE SHOP FAN IS USED. I HAVE NOTICED A HIGH COMPRESSOR REPLACEMENT RATE (LISTED ON IDENTIFIX) BUT NEVER A REASON WHY THE COILS GO BAD. WHILE THE A/C IS COOL, IT IS NOT COLD ENOUGH. I DONT THINK IT IS A BLEND DOOR DUE TO THE SYSTEM WORKING FINE WITH THE SHOP FAN. IM ABOUT TO TEAR MY HAIR OUT!!!

the answer could be as simple as too much oil or refrigerant. in the past i've added oil when replacing a compressor only to find out that there was already oil in it. the result was close to this. is there an air flow restriction? i've seen debris between the condensor and radiator. everything is so critical in today's vehicles, even a small restriction will cause an issue. it sounds that you're repaired the end result of a problem but the cause is being elusive. i wish i could take my own advise when i say to take it easy and start over with a step by step diagnosis treating it as it came into your shop with the problem as it exists now. sounds simple, but i'm guilty of overlooking obvious repairs when i get into these situations. is the fan blade spinning on the shaft? is this s three stage fan? look at the wiring schematic. the answer has to be with the fan or air flow. on one occasion i ran into an issue where a fan had been wired backwards.

Allen, dont pull any more hair out, you will end up bald like me. Lets start from scratch. Turn off the shop fan. Take these readings at idle, blower set to HIGH, windows down. Give us high side, low side, center vent, ambient temp about 4 feet in front of the car. If its 110 outside, 275 isnt very high for the high side and 50 vent temp isnt too bad. If its only 70 outside, then that changes things. Next you will want to list in & out temps of your evap core and condenser. Preferably with a contact thermometer like mentioned before. Also, like mentioned before, refrigerant and oil charge are critical. Let us know what you end up with. The more we know, the more we can help.

You are right about the high clutch failure. Seems that the power going through the relay suffers a real amp loss seems they under rated the heat factor Ive not seen a TSB for a secoundary relay fix yet. Seems that and I agree that the system might have to much oil !

THE AMBIENT TEMP HAS BEEN IN THE 90'S WITH A CENTER VENT OUTLET RIGHT AT 50 ON RECIRC WITH THE WINDOWS UP. tHE HIGH SIDE WILL CLIMB TO 275 AT WHICH TIME THE FAN KICKS UP TO HIGH SPEED AND BRINGS IT DOWN TO ABOUT 185. THE LOW SIDE COMES UP TO 32 AND DOWN TO 25. CONDENSOR TEMPS RUN 120 OR SO.WE HAVE CHECKED THE FREON LEVEL A DOZEN TIMES WITH A COMPLETE EVAC AND RECHARGE (0.91 LBS). THE OIL LEVEL SEEMS OK DUE TO HAVE MEASURED THE AMOUNTS IN AND OUT. IF ANYTHING IT COULD BE A TOUCH LOW. MY EVAP IN AND OUT ARE HARD TO GET A REAL ACCURATE READING DUE TO THE LOCATION, BUT THEY SEEM TO RUN AROUND 100 OUT AND 70-80 OUT, ALTHOUGH IM SURE THE OUT ISNT ACCURATE BECAUSE OF THE VENT TEMP OF 50. ALL THIS IS WITHOUT THE SHOP FAN, AT IDLE. WITH THE SHOP FAN EVERYTHING WORKS GOOD WITH A HIGH SIDE OF 200 OR SO, LOW SIDE OF 25-30 AND VENT TEMP OF 40-42 ON RECIRC, WINDOWS UP AND IDLING.
I APPRECIATE ANY AND ALL HELP, AS I HAVE AN UNHAPPY CUSTOMER!

When I was workin for Chrysler ( in Florida) a 40 degree gain was acceptable. In looking at the last post I would think the charge is a little low. High side press at 185 with fans on high and low side at 25 I would consider low. If the car was travelling at 50 mph the air flow across the condendor is comparable to the shop fan running. It may be the customers expectations cant be met. Just my 2 cents worth.

A 40 degree difference (from 90-50) at idle is not bad at all. What happens at say 1500-2000 rpm? If it gets in the mid to upper 40's at the higher RPMs, then I say that's about as good as it gets in some vehicles.

A 40 degree drop is good. Your profile doesnt list where your shop is. If its humid, a 40 degree drop is darn good. Cant tell you much more than that without accurate temp readings from evap & condenser core.