Is A/C Conversion to R134a Possible? - PeachParts Mercedes-Benz Forum

MB-Dude · #1 09-08-2007, 12:49 PM

The A/C in my '79 240D has always been anemic and I suspect there is a leak somewhere since it's never really produced frigid air. I'm not expecting polar blasts from this completely stock, OEM air conditioning system powered by a 2400cc diesel engine, but would expect air cooler than the outside air!

That said, I'm seriously considering taking the car to a dedicated A/C Shop in town and having them 'overhaul' the system - check for leaks, make repairs, clean out/flush the system, etc. I expect them to find a leak or two; hopefully nothing too expensive to fix.

Question - With all this work being done, is it possible to convert the existing OEM system to R134a at the same time?

I would seriously consider this as A) R134a is more environmentally friendly than R12 (though still not perfect) and, B) I can legally work on the system (recharge, etc.) in the future as a DIY mechanic. (There are restrictions for discharge of R12, for example.)

Cheers,
Jeff

Matt L · #2 09-08-2007, 02:27 PM

The restrictions on discharging are the same for any automotive refrigerant. It's particularly silly to have such restrictions on discharging 134a, since you can buy cans full of it which are intended to be discharged, but the restrictions are there nonetheless. The rule is, if it is a refrigerant in a car or sold with the intention to go into a car, you can't discharge it, regardless of the chemical makeup. You can thank the mobile air-conditioning society for that one.

You can take an online test for about $20 which will enable you to legally purchase R12. There is still vast quantities of the stuff for sale in this country. Sure, the price is higher than for 134a, but it's still almost the cheapest part of the entire system.

Ed Richardson · #3 09-08-2007, 04:52 PM

I had my '77 and '86 converted and both worked fine in So. Cal. I have heard that it is not as effective for desert climates.
Ed

bolomiester · #4 09-08-2007, 05:04 PM

Have it converted to R134a but charge it with one of the HC12 replacements. They are more efficient than R12 or R134a, take less material to charge the system, and cost less. They are also more environmentally friendly, and do not require a change of the oil type. It is compatible with either.

My favorite brand is EnviroSafe, as they have a product that will seal small leaks in the metal parts of the system. I've charged two leaking sytems with it and have been very satified. Both now cool well and don't leak.

Matt L · #5 09-08-2007, 05:28 PM

Quote:

Originally Posted by bolomiester

Have it converted to R134a but charge it with one of the HC12 replacements. They are more efficient than R12 or R134a, take less material to charge the system, and cost less. They are also more environmentally friendly, and do not require a change of the oil type. It is compatible with either.

My favorite brand is EnviroSafe, as they have a product that will seal small leaks in the metal parts of the system. I've charged two leaking sytems with it and have been very satified. Both now cool well and don't leak.

Were it not for the fact that this is illegal under federal law, it would be a great idea.

petaling · #6 09-08-2007, 06:11 PM

Quote:

Originally Posted by bolomiester

Have it converted to R134a but charge it with one of the HC12 replacements. They are more efficient than R12 or R134a, take less material to charge the system, and cost less. They are also more environmentally friendly, and do not require a change of the oil type. It is compatible with either.

My favorite brand is EnviroSafe, as they have a product that will seal small leaks in the metal parts of the system. I've charged two leaking sytems with it and have been very satified. Both now cool well and don't leak.

I used RedTek which is R12a similar to EnviroSafe E12a,and a can of Pro-seal supplied by RedTek,
now I got a 5 yr non-functioning A/c working.Total cost:100$.I still have a can to spare for next summer.

Moonlighting MB Mechanic's estimate (not 100% guarantee either=1000-2000 to replace evap etc)but there is no guarantee that the 2000 will solve problem for long,he says.I saw him drove a A/C less MB himself!!!!

truckinik · #7 09-08-2007, 06:43 PM

You can convert literally anything from R-12, to 134-A. All it consists of is blowing out the old stuff, putting the adapter fittings on the inlets which attach to what's there already, and charging the system.

The question is, WHY would you unless you had no choice..?

134-A, Is more environmentally friendly but nowhere near as cold, if you compare the two of them. Most people wait 'til the very last possible minute to make the conversion. As long as I can ever still get R-12, I will keep my systems running on it. Until the supply of R-12 is totally gone, everywhere, I will use it until it's not available and I haveto switch over. Just my two cents...

wscheffer · #8 09-09-2007, 06:36 AM

Quote:

Originally Posted by bolomiester

Have it converted to R134a but charge it with one of the HC12 replacements. They are more efficient than R12 or R134a, take less material to charge the system, and cost less. They are also more environmentally friendly, and do not require a change of the oil type. It is compatible with either.

My favorite brand is EnviroSafe, as they have a product that will seal small leaks in the metal parts of the system. I've charged two leaking sytems with it and have been very satified. Both now cool well and don't leak.

It contains hydrocarbons! And after it is in the vehicle the shops will not touch it.

brewtoo · #9 09-09-2007, 08:27 AM

Quote:

Originally Posted by Matt L

Were it not for the fact that this is illegal under federal law, it would be a great idea.

So is Illegal Immigration. Nobody seems to care much about that, though. Probably some guy using an Illegal refrigerant would matter more.

Matt L · #10 09-09-2007, 09:34 AM

Quote:

Originally Posted by brewtoo

So is Illegal Immigration. Nobody seems to care much about that, though. Probably some guy using an Illegal refrigerant would matter more.

Oh right. Some Joe Blow breaks the law, and thus you don't have any obligation.

brewtoo · #11 09-09-2007, 10:20 AM

No, it's just that a society tends to ignore big problems that are hard to manage, while focusing on smaller issues that are easy to manage.

For example, citing people for rolling stops is easier than catching murderers and rapists.

Of course, this does not even address the fact that Illegal immigration IS causing problems, while Joe Blow putting some Illegal substance in his air conditioner MIGHT be causing problems.

If it makes you feel better, I did replace the evaporator in one of my cars this year because it was leaking evil chemicals into our atmosphere. So even though I still use R12, I'd say I'm doing my part for the environment.

Matt L · #12 09-09-2007, 10:54 AM

Don't get me wrong. I think the laws are silly.

You can convert a 134a system to hydrocarbons, but not a system using R12. Very silly. Sillier so if you consider the fact that it is easy to put HC-specific fittings on the old R12 systems, and very hard on a 134a aystem.

You can buy canned "air" which is pure 134a with the intention to vent it all to the atmosphere, but you can't vent the same chemical once it is sold for an automotive air-conditioner application. Very silly. Tons of the stuff are vented legally.

The problem isn't that the laws make sense. The problem is that while you're unlikely to get caught, the fine is quite severe if you do.

MB-Dude · #13 09-09-2007, 12:39 PM

Thanks to all who responded - far too many to address individually. While it was not my intent to get into a political discussion, I can see where there are parallels. But you have to admit, at first blush who could make a connection between A/C Refrigerants and Illegal Immigration?!?

At any rate, my query was simply to educate myself as to whether the conversion was possible and if anyone had performed it before; pros, cons, hurdles, etc. I plan to visit the A/C Shop this week to look over their facilities, methods, etc. Armed with some thoughts presented here, I can now speak with confidence as to possibly 'upgrading' the system to R134a. I do not have to change from R12; simply wanted to ask the question here. All things being equal, I would prefer to stay with R12 for reasons stated in one or two of the responses; i.e.: cooler air output.

Thanks again guys for the input and thoughts. It was quite helpful to me. I'll let you all know how it turns out, one way or another, when I get my 240D 'up to snuff'.

Cheers,
Jeff

brewtoo · #14 09-09-2007, 12:40 PM

Well, I believe that if we are not going to enforce a law, we should rescind that law.

The way our leaders and enforcers pick and choose which laws to enforce teaches the public to have less respect for the laws and rules in general.

So, if it is a law, enforce it. Do not discriminate in enforcement. For example, do not be writing someone a speeding ticket while 200 other cars are driving by speeding as you write the ticket.

If a law is not worth enforcing (aka respecting), get it off the books.

And regarding the original question here, converting to 134 is no upgrade. IMHO, of course.

Matt L · #15 09-09-2007, 01:26 PM

I agree with your post in all respects, Brewtoo. Especially with not needlessly converting to 134a from the far better performer R12.

I've always thought that we need real speed limit signs with actual enforcement. The highway near my house has a posted limit of 65, but you don't get a ticket by blowing by a trooper at 78. Have the signs say 80, and mean 80. But especially with speeding laws, this will never happen. Selective enforcement brings the cash in.