Retrofit A.C. to a 240D

My A/C shop told me last week, when I had the A/C recharged (w/ R-12), that the price of R134a had been vastly increased in the last year. So I suggest you first look at the economics before the conversion.

I paid $160, including labor, for a 1.5 lbs R-12 "top up" (last recharge was in 1998).

I was under the impression that R-12 was very scarce but its apparently being recovered from old cars etc., purified and repackaged in 12oz cans. Perhaps "new" R-12 is scarce or not available but the reclaimed gas works fine.

Do you mean your 240D has no A/C now? If so, this is quite a project.

Wouldn't that be against the law in the US ? I don't think it's allowed to be resold?

I think the original posters best bet would be to find a donor vehicle with a complete AC system and transplant it. Using R-134a of course.

Marty

Thanks to everyone that responded.

Ouch! $160 for a refill, phew!

The local MBZ rep returned my call with quite shocking information last evening. For example, a new compressor would cost about $750 and the bracket that holds it about $625. All components together would likely cost $10,000!!!!! The car is probably worth less that $4,000. He suggested visiting the breakers yards and doing some salvaging. However, from TGL's info, I would be stuck with the R-12 for the older system.

I need to look at my manuals to see how many components are present in the a.c.system and try to figure out what other work would be required, apart from installing the compressor, fan, bracket, belt, connect ducts, etc

Dilemmas, dilemmas :-(

JJ

well that answers that an MB with out fACTORY AIR! thought that was agenest the law.

go to an auto AC installer and tell them you want an underdash unit

they may now have split units for under driver & pass sides

i really don't know.

with $ you can do anything

the case, minus a few cans!

Don't take an old car to a dealer - unless you have very deep cash reserves. Go to an A/C shop.

Converting an existing R-12 system to the new R134a is about the easiest thing I've tackled on an MB. All you do is go to someone like Pep Boys and get the valve conversion kit. Also buy a new dryer as the old one will normally be saturated with oil-laden R12. Drain the system completely. Frankly I subscribe to Scientific American Magazine and they ran an article several years ago stating that the ozone "hole" over the south pole is a

50-year cycle thing and has very little, if anything, to do with R-12 in the air. Go figure. Change the valves to the new type and install the new dryer making sure you leave the system open no longer than necessary. This is to keep moist air from entering the system, especially the dryer. I have a vacuum pump and a set of both R-12 and R-134a guages. Pull down the system down as close to 30 inches of mercury as possible, turn the valves off, sealing the A/C system. This is to make sure you have no leaks. After sitting an hour or so the system should hold the vacuum originally pulled. If not you have a leak and need to to some searching. If the system is tight you can now begin filling with the new R134a. You will need to take the pressure valve out of the circuit at the dryer location. On my 240D its on the passenger side, under the hood located forward and down low on the inner fender. Pull the wire connector from the pressure valve and insert a wire loop to complete the circuit. Start the engine, put a block of wood or similar device under the "Stop" lever on the linkage to get about twice idle speed. Begin loading your new R134a. R12 systems require about 30-34 lbs on the low side and I'm told you only need about 28 psi with the R134a. I brought my wife's 300D up to 30 psi and it works just fine. Once your done don't forget to remove the block used to increase idle and the wire loop on the pressure switch. With the wire connector reattached the compressor should work fine and your system should now produce cold air. Incidentally, I've never seen an R134a system that will blow as cold as a good R12 system. Any takers?

Thanks Ernie.

This is a priceless post heading to my archives.

I'm curious to know how reliable the MBZ A.C. systems were in those 1980s. Did they tend to wear out or did they age gracefully and reliably like the other parts of the cars.

Cheers

JJ

when he says refitted with AC it sounds to me that the car never had AC in it.

the case, minus a few cans!

So you violate the EPA law by dumping R-12 into the atmosphere?

They are garbage.

The car never had A.C. I live on the central California coast where the off-shore Pacific is about 50 degrees F. year round. I don't need it here.

It seems to me that, unless the A.C. is VERY integrated into the engine and body, a non-MBZ a.c. might be installable. A Toyota unit should be reliable :-) A.C. is just a reversed refrigerator. I guess a visit to an A.C. shop, as T.G. suggested, would be a good idea. But then I'm sure there are good A..C. shops and bad ones. Shop around man ;-)

Thanks again

JJ

Yeah and the earth is flat, and white people are superior.

Isn't science great?

Freon is a direct contributor in an exponential way to the degradation of the ozone layer.

DISPOSE OF YOUR FREON PROPERLY!

It should be extracted by a shop with the proper equipment.

Marty

It's definitely installable, but it is too complicated to be justifiable in term of the effort and expense. After market system might be a better solution.

Marty

I've never had what I considered a serious problem on either my 240D or

300D, both '81s. I did replace a compressor and dryer on the 300D but that was relatively simple and I converted to R134a at that time. Wish I hadn't converted. Nothing cools like the ole R12. Can still get it in Mexico in the small 1-lb cans. Isn't it funny how R12 works okay in Tijuana but is "deadly" in San Diego. Go figure.