Strange things are happening with my air conditioning system.

It started blowing hot air...I live just outside of Phoenix...I bought a case of R124 at Sam's Club and re-charged the system.

Here's the strange part. It blows cold for a day, a week and then it blows hot again. Sometimes it does it the next day, but always, while the car is running the air is ice cold.

Can someone tell me where the most likely place for a leak would be?

Also, is there some type of lubricant that is embeded in the R-124?

Thank you for your words of wisdom.

I think you mean R134a? Unless you buy the oil charge can, there is no lube.

Sounds like a leak. You can sometimes see where the leak is by looking at the lines and finding an oily portion. The oil is like a mineral oil, so look for a light oil on the lines.

You can also buy the fluorescent oil and charge with that, then park in a dark place with a blacklight. Good luck!

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT

I don't understand the statement "...but always, while the car is running the air is ice cold."

Please explain.

Best Regards,
Rob

__________________
Robert Fini

'12 ML350 BlueTec, 87k
'06 E320CDI, 270k
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 69k
'97 C36AMG, 313k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)

To: Rob Fini

I could drive the car from Phoenix to Lake Havasu or San Francisco after recharging the system and the air will blow ice cold during the entire trip. It only seems to lose its charge when the car is turned off. So the leak does not happen whilst it is running...that makes no sense to me.

Thank you Zeke...thank you Rob...for your inputs.

I'm still confused.

You said that it sometimes goes days or weeks and works just fine, then for no apparent reason it stops blowing cold. You also said that it always works when driving and only stops working after the car has been sitting. I assume that the car sits sometimes during the days/weeks that it keeps working, yes?

Are you recharging the system every time in order to get it working again or is there something else that you're doing to get it to blow cold again? Do you have pressure gauges to measure how much refrigerant you're adding?

__________________
Robert Fini

'12 ML350 BlueTec, 87k
'06 E320CDI, 270k
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 69k
'97 C36AMG, 313k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)

"You said that it sometimes goes days or weeks and works just fine, then for no apparent reason it stops blowing cold. You also said that it always works when driving and only stops working after the car has been sitting. I assume that the car sits sometimes during the days/weeks that it keeps working, yes?"

Yes!

And that's the strange part. It will work for a week and then the cold air stops coming, I'll re-charge it, sometimes it works for a day, sometimes a week...there is no pattern here.

I do not have gauges, except for the one in the recharge kit I purchased from Wal-Mart.

So you recharge it every time it stops blowing cold. It sounds like you have a leak. The best way to approach this problem is to put UV dye in the system, run it until it's not cold anymore, then look for the leak with a UV light.

You should have a professional look at it. They have the UV dye and UV light to diagnose any leak. Every time the system leaks, some lubricant escapes with the refrigerant. If you keep topping the system off you could ruin the compressor by letting the lube run dry.

Like zeke said, if refrigerant (and lube) is leaking, you may find the leak by looking for a wet spot on the system. Unfortunately, the evaporator is a known weak point for these models, and it is horribly difficult to diagnose and replace a leaky evaporator.