Guys,

The AC in my 2008 Cooper S has seemed kinda weak lately and Ive been getting what Im pretty sure is a refrigerant smell inside the cabin at startup. (not engine coolant, but rather R134a refrigerant). SO I assumed I had a refrigerant leak.

I checked low and high pressures using an AC gauge set and I cannot get the pressures above 30 psi low side and 90 psi high side on a 75 degree day. So I added 12 oz of R134a with UV leak finder dye and leak stopper. Still...pressures are the same, and car only cools to 60 F at the center vent, window open, not recirculating cabin air, on a 75 degree day.

So my buddy looks through his ALLDATA account and finds that its only supposed to cool to 60 F!!!! WTF. Most systems cool to near 45 F. Strange.

Anyway, poking around looking for any signs of a leak using a black light I realize the heater core is blazing hot; both lines, in and out of the core, even though I'm asking for no heat.

I'm confused about the heater core being 200+ degrees on both in and out pipes and why AC is only supposed to cool to 60 F. Maybe the

Anyone have any experience here? Anyone know the Cooper Specific pressure readings for the AC system?

The generic pressure table is:





ALL DATA 64 50 ... A/C performance test (R134a)

Observe the following conditions prior to the A/C performance test:
Connect BMW diagnosis system. Check of the fault memory (no faults in the fault memory).
Attach a thermometer with separate display device to the head restraint and route the display device wiring out of the passenger compartment outward.
Perform the test in a suitable workshop area with an ambient temperature above 18 °C.
Vehicle temperature should be approximately the same as the ambient temperature in the workshop.
Engine must be at operating temperature.
Heat passenger compartment:
"A/C button" is not activated during the heating process
Close all windows and doors.
Set air recirculation function.
Select air distribution mode for footwell and defrosting.
On vehicles with CID: In A/C menu (CID) in Air distribution index tab: select 100 % footwell for driver and front passenger and 100 % defrosting for driver (this applies here to driver and front passenger)
Maximum temperature setting
Maximum blower speed
Start engine
Cool down passenger compartment:
Turn on air conditioning compressor with "A/C button" at a vehicle interior temperature of 45 °C (measured at the head restraint).

On vehicles with MAX AC button:
Activation of MAX AC (= maximum cooling power)
On vehicles without MAX AC button:
Set maximum cooling power by means of following steps:
Setting minimum temperature
Blower setting maximum
Stratification maximum cold (4 blue bars)
Only ventilation open
Close remaining flaps (air outlet only from centre fresh air grille, left and right)
After 5 minutes measure both ventilation temperatures with a thermometer at the same time (fresh air grille centre, left and right). The measured temperature must be

 

I found a really nice diagnostic chart.

 

You need to find a qualified AC repair shop that has a recovery unit who can measure how much refrigerant is in the system, as well as vacuum test the system for leaks.

Does the car have auto air? Have you checked to see if the cabin temp sensor is covered in crap?

Also any type of stop leak in any system is a huge no no unless an absolute emergency.

 

Dont wanna pay someone. Im gonan evacuate myself and put a vacuum on it.

Yes I have autoair but I never use the auto function. I though about the evaporator temp sensor as a possible culprit.

I have not checked the cabin temp sensor yet. But that would not result in lower than normal pressures on both sides.

 

The refrigerant measurement needs to be precise, you cannot properly charge the system without an AC machine. Pressure and quantity are two different variables and the fact that you're pressures are low on either side of the system really only leaves; faulty expansion valve, underfilled system (or a leak), or possibly a faulty compressor.

 

thanks for the input. I realize that pressure and weight of refrigerant arent a perfect correlation. I think the system is overfilled at this point, but pressures remain low. One thing is evident...I dont smell any more refrigerant smell when I turn the car on. Meaning the leak seems to have been plugged by the leakstopper.

Nonetheless I will need to evacuate and replace the expansion valve.

 

hello did you even replace your expansion valve.
? if so where is it located?

 

I havent but Im going to have to very soon. Its on my list.

The problem isnt it's replacement as much as all the other steps you need to take once youve changed it. Pulling vacuum etc.

 

Hi Lex,
When new my Clubman only blew ~55-60 degrees at 80 degrees outside. I had it checked by MINI and they said all was OK. So yes, this car's A/C is weak compared to other cars I have owned. But at least it's still working with all original parts and refrigerant charge.
Don't overcharge it, if I recall there's only about a pound or so of refrigerant in the system.

 

wow...that's not industry standard. Should be 50 or less.

 

any progress? i would like to know the root cause.

 

Lex2008, did you find out the problem?

My AC is not blowing cold. Manifold gauge shows the low side has 25psi and high side around 50psi. I am leaning toward the AC compressor.

Let me know if you find something different.

 

My bro, our systems may be malfunctioning for totally different reasons.





See:http://www.aa1car.com/library/ac98.htm

see: https://www.2carpros.com/articles/ca...ing-or-is-weak