sweeper

Has anybody upgraded the capacity of the airconditioner for an ML320. The reason I ask is that downunder, when the outside hits 40 deg C + the aircon throws the towel in. I have measured the temps over the last few weeks that I have been having issues and have the following results.

Remember all these temps are in celcius

Outside 37 fan pos 1 minimum temp at outlets 24
Outside 37 2 26
Outside 37 3 30

The cars internal temp is about 41+

Now without any fan and just ambient air flowing through the car I can get the outlet to drop to 8 with an outside temp of 24 so the airblend motor is working etc..

So, has anybody increased the cooling capacity of the aircon by replacing the stock evaporater with a larger one, or, totally replaced the aircon unit with one from another MB, or even ditched the MB unit altogether and replaced it with an under dash unit?

From what I can gather unless the aircon unit is a pisspoor unit, my car is a "made for the UK (who needs and aircon but the heater is like a blast furnace) and sent to Australia"

Any ideas to improve the aircon's performance would be appreciated. I have already dumped the r gas and put in new gas "ezychill", I have already replaced the TX valve and receiver/drier.

Thanks

sosh

You don't mention the year of your ML. I believe that the A/C is the same for all vehicles (ML) regardless of where they are sent. My first ML was a 1998 ML320. I owned that ML for about 4 years. I do not recall ever having a problem with the cooling capacity of the A/C. We have temps here ranging up to the high 90s (F) in the summer. What I would suggest is that you have a good A/C shop or a dealer with a good A/C tech run thru the entire A/C unit and be certain that all perameters meet factory new specifications. Never heard of the gas you are using but I would put the MB suggested gas back in it. I have never heard of anyone with your issue before. Have you had the condenser cleaned? or the evaporator cleaned externally?

gsfent

Do you have a gauge to measure both the low side and high side pressure? Too much gas will make the AC inefficient.

I thought EZ chill is a replacement for r12. I am pretty sure your car uses r134. Not sure what "TX" is unless you mean expansion valve?

I would take the car to a shop that specializes in AC systems. Nothing magical about MB AC. The system should be strong enough to take care of your needs, my 2002 handles the south Florida summer heat reasonably well; it can take a few minutes to cool off if left in the summer sun when interior temps can well exceed 100 degrees F.

Regards,
Jerry

Maj. Dundee

Sosh and gsfent have provided good information. The only proper way to charge an A/C system is with a charging station which every A/C shop has. With it the precise amount of refrigerant can be entered.

The precise amount is 750 grams or 26.4554 oz's. Over charging is just as bad as under charging, sometimes worse. When working with R134a, the precise amount is needed, not the "about" amount. This ezfill that you used is just a Mickey Mouse product and way of doing things. You can do what you want, but that stuff should be evacuated and charged with the proper amount of R134a refrigerant.

You don't even mention what year your Ml is, as different years have different compressors which operate differently.

The first thing you should do is check your cabin air filter for debris. If it is clogged or blocked by leaves and such, it will not let the blower air to pass to and through the evaporator.

There is no upgrade that you speak of. Changing the evap. is a two day job and should only be considered if it is leaking refrig.

sweeper

Thanks for the info. Well, I am more convinced that a trip to a shop is required. The TX valve is the expansion valve, different terminoligies for the same Item. The gas was replaced by a refrigeration mechanic using gauges so it "should" be the right amount. It's a 2000. And one more piece of info, with the cabin filter out of the car and no fan, just ambient air flowing into the car, I managed to get the air down to 8c from an outside temp of 31c. Perhaps it is just bad/poor airflow as if the fan is cranked up the cooling effect decreases remarkably.

So its off to the shop, get a new cabin filter, see what the aircon people make of it. Thanks for all the advice guys.