'90 240 r134a conversion specifics

[benemorius]

I have an '89 and '90 240 both lined up for r134a conversions and I'm having a hard time finding any sort of bulletin from Nissan on what the recommended procedure is. I have read that the kae compressor is 134a compatable and that PAG 100 is the recommended oil, but not from any reputable source. Is that accurate? Is the condensor going to be big enough? Is there an expansion valve replacement available that is calibrated for 134a? Is this one adjustable? Can somebody see if Nissan has an article on any of this stuff? Thanks.

[NISTECH]

Nissan nor any other source is going to put anything definite in print. however the recommended way to do this is to remove ALL your a/c componets and completely drain all oil from them. It is also recommended you replace the reciever dryer in the process. Once ALL oil is extracted from the system you should be able to safely add Pag oil and charge it with 134 and it should operate normally.

[NISTECH]

oh also note when you switch your will have up to a 5 to 10 degree higher out put temp as r134a does not have the same cooling properties as r-12 does. This is the reason for using a larger condensor.

[benemorius]

Nissan didn't print anything at all about this? What do you guys do when a car comes in wanting a retrofit? When I worked at a Honda dealership, we had bulletins on procedures for converting various vehicles. Sometimes it said that particular compressor had to be replaced, sometimes the hoses had to go. It was frequently safe to just flush evac and recharge, but Honda at least had the documentation and replacement parts available for most vehicles.

[NISTECH]

You know actually all the crap about the coagulation of the 2 different oils seams to be a myth anyhow. But no nissan has this thing about not acknowledging anything they built in the past as having any importance in the future. All they are concerned with is what is still under warranty and what they are going to build. So no TSB was ever issued covering this.

[benemorius]

5 to 10 degree increase??? I'd better have at least a 35 degree decrease seeing as the a/c currently doesn't work at all.

Ok sorry bad joke.

[benemorius]

Ok well thanks for checking. I must say I'm surprised and dissapointed.

Well then in that case, do you (or anybody out there...) have any personal experience with converting this or similar vehicles? I was hoping to hear something like Nissan says I need expansion valve part no. XXX for optimal efficiency, but at this point I'd be happy even to just hear whether or not the seals in the compressor will hold. That's my main concern as it can mean the difference between a merely nonfunctional system or a shot-to-sh** compressor, condensor, and evaporator, and most importantly a very pissed girl-who-owns-one-of-these-240's.

[ricebike]

hmm, i read in most aftermarket recharging/retrofitting kits that u should use only 85% of the stated r12 spec to refill the system (if you're not going to change any components) that way, you won't blow the seals...

the aftermarket kit had a special oil as well so it won't combine w/ the residual r12 oil...Polyol Ester oil

i didn't retrofit, but recharged wifey's honda accord w/ the kit...very simple & will have to plan to vacuum out the system & do a total recharge in the near future.

http://www.id-usa.com/how_to_faqs_retrofitting.asp

[benemorius]

It's not necessarily about blowing the seals, but you do indeed charge oem r12 systems with less 134a than you would with 12.

The ester oil is used when you don't plan to completely flush out all the remaining r12 and mineral oil. The mineral oil cannot be used with 134a not because it will mix and cause damage, but rather because it will not mix. Mineral oil will not dissolve in 134a and therefore will not be circulated. It doesn't really harm anything to leave it, but it will collect in places like the evaporator and condensor, and I can hardly imagine that does any good for performance. PAG is normally used (such as in new cars) with 134a, however PAG oils are completely and utterly incompatable with any traces of chlorides. As r12 is a CFC, it breaks down any PAG oil it comes in contact with. You're just asking for trouble if you add PAG oil without removing every trace of chloride from the system. There is even some hype about aluminum chloride forming on the walls of the aluminum pipes that is impossible to flush out. Ester oil is great because not only will it not combine harmfully with r12 or r134a, but it will even dissolve in both. Still, PAG oil is preferable as it is what oem's specify.

Just curious - for what reason did the accord need to be recharged? Retrofit kit instructions can be extremely misleading to anyone not familiar with a/c systems. The main problem is that they never mention the need to pull a vacuum on the system or replace the dryer if the system has been opened or completely empty of any refrigerant for longer than a few minutes.

[benemorius]

ugh

Interdynamics needs to be burned at the stake. I was just reading through the faq you linked to (no offense to you) and the amount of misinformation I found in the short while I spent looking was enough wipe out a moderately sized third world country.

[Touchdown038]

I did a R134a retrofit on my 89 240 last year, and it's still running great. It's not the greatest while at idle when you first turn it on, but once you're cruising it works great.

All I did was have all the parts flushed, ordered new expansion valve, receiver/drier, and rubber seals, and threw it all back together and charged with ~32 ounces of R134a and a small can of Ester oil. Works great!

I think that all of the parts made to work with the R-12 also work with R134a, at least I have had no problems with them so far.

[benemorius]

Thanks for the input, Touchdown. Sounds promising. Did you get a new expansion valve because your old one was shot, or is it a different one that is for 134a?

[Touchdown038]

I'm not sure about the condition of the old one, but I figured that since I had a failed compressor to begin with, there were metal flakes throughout the system, so I just replaced the valve to be sure.

It's a good idea, but probably not required during A/C service.

[Joe]

5 to 10 degree increase??? I'd better have at least a 35 degree decrease seeing as the a/c currently doesn't work at all.

Ok sorry bad joke.

*psst* increase means the air gets warmer

R134 in a R12 system will blow 10 degree WARMER air. meaning at peak if your ac was doing 45degrees out of the vents, it will now do 50-55.

[NISTECH]

Nah he was saying it is blowing about 100 degrees now. He just wants that number to fall at least 35 degrees..I cant contend with that..lol

[Joe]

thats what i get for not paying attention

back to my hole, the RB forum.