s13 can a r134a compressor be used on r12 system?

[89S13 Drifter]

I am converting my car to r134a, and I have found out my compressor is bad or so says the garage. It won't go over 140psi on the high side. I found a used r12 compressor for $100 and a r134a compressor for $45.

So i was wondering since I am going to be useing r134a in the system will the r134a compressor bolt up to the bracket on the engine and accempt the lines to it and use the same belt and belt alignment?

Or does anyone think its not the compressor? When I tried adding the refrigerant myself I couldn't get it to take more than half a can at a time, but sapposedly the garage guy said it took 2 full small cans of refrigerant for him. So the system should have enough refrigerant in I would think between his 2 cans and what I had in it.

My light does not come on when I select ac in the car but my rpms change from the compressor kicking on. Also according to my thermometer in the vent it is blowing 98 degree air. Which is only slightly lower than the 100 degree cabin temperature.

Any help would be much appreciated

[inshje01]

zerothread?id=188583

This is the thread I started, might have some help for you in about the AC light not coming on. I am in a similar situation, but I think my compressor is dead altogether. Unless you actually see the compressor kicking in, I wouldn't be so sure that that is not the problem. Mine does not kick in at all, which is why I think I need a new compressor.

I was about to start a thread asking about compressor prices and how long/hard it is to do the installation, however, I think I am going to piggyback/threadjack your thread. At least if any more answers surface here.

[89S13 Drifter]

You can buy r12, it is just expensive and you need to have a EPA licence to handle refrigerant. Go to http://www.epatest.com and for about $20 you can take the 609 automotive MVAC test and get your licence to buy and handle but not sale r12 or any refrigerant under a 20lbs container if I remember correctly. I am currently in AC&R school in the Navy earning my 608 universal certification that will allow me to buy larger than 20 lbs but not work on car MVAC systems so I am going to take the 609 test online so I got all the licences coverd. Still r12 is expensive to buy but if you get it and the equipment to handle it you can make $ servicing r12 systems around your area buy running a small business. Just make sure you don't purge to the atmosphere as you get in serious trouble especially if you are a licenced handler.

Also I saw a website if you search on google for something called freeze 12 that is sapposed to be a dirrect non CFC replacement for r12 that works better than r134a. I would try it but I don't have a mailing address where I am stationed.

Also I found out my light is on now but my AC is blowing 110 degree air. And my RPMs shift so I know my compressor is loading. But it might be as the tech said it isn't compressing enough. r134a needs to run at a higher pressure than r12 to work as good that is why r134a doesn't feel as cold in a r12 system cause it is allready running at a lower than optimal pressure.

[89S13 Drifter]

Bump

[Touchdown038]

A/C is one of those things where it's better to bite the bullet and have someone do it properly for you. Having said that, it is easier to do everything except recharging as long as you know a little bit about the system. A/C, though, is one of those systems where exact measurements are key. Too much pressure can be just as detrimental to the system as not enough pressure.

Also, I honestly would not recommend that you convert the car to r134a. I did it a couple of summers ago myself and it never really did work very well, only slightly cooler air when on the freeway.

I'm not sure about Freeze 12, but I would stick to one of the approved refrigerants if I were you. I'm not though, so go ahead if you feel so inclined.

I didn't know there was an R-12 compressor and a R134a compressor... I thought there was only one...

[benemorius]

I'll assume we're talking about an 89 240 based on your name.

If the engine idle changed but your light didn't come on then that's just something wrong with your light. Ignore it for now.

I am not aware of any R134a compressor for an 89 240, so I'd find out exactly what that is.

The system doesn't have his two cans plus your half can. It has only his two cans because he changed the drier and properly evacuated the system before adding anything. If he didn't then he is incompetent and you need to find someone who knows what they're doing.

You also need to find another mechanic if he told you the compressor is bad and you don't completely believe him.

For the record, and most respectfully, R134a works swell in 240s. A minor drop in performance is noticed as is to be expected, but if it isn't working well at all then something hasn't been done properly.

[jdm_master_X]

you cannot mix R-134a and their components that ran R-12 previously. reason is because the oils that are carried within the refrigerants are not compatible with each other, and can gunk up and clog the lines. so when doing the conversion, you must get the entire car retrofit for R-134a (nissan sells the kit).

R-134a operates at slightly higher pressures than R-12, and boils at a higher temperature than R-12, but is just as efficient.

you can go ahead and keep R-12 if you can keep on affording to buy it. It's getting expensive.

the lines for R134a have different flanges and connections, so quite possibly the connections to the compressor might be slightly different.

you'll be in for a treat if you mix the systems....but if you do retrofit, make sure to get ester oil, at least thats compatible for both systems during the retrofit process.

[benemorius]

you cannot mix R-134a and their components that ran R-12 previously. reason is because the oils that are carried within the refrigerants are not compatible with each other, and can gunk up and clog the lines. so when doing the conversion, you must get the entire car retrofit for R-134a (nissan sells the kit).

R-134a operates at slightly higher pressures than R-12, and boils at a higher temperature than R-12, but is just as efficient.

you can go ahead and keep R-12 if you can keep on affording to buy it. It's getting expensive.

the lines for R134a have different flanges and connections, so quite possibly the connections to the compressor might be slightly different.

you'll be in for a treat if you mix the systems....but if you do retrofit, make sure to get ester oil, at least thats compatible for both systems during the retrofit process.

I don't mean any offense, but none of that is true except the part about ester oil.

R-12 is a CFC and thus contains chlorine. Chlorine is not compatible with PAG oil which is what is standard for R-134a systems. Even after removing the R-12 there will still be remnants of chlorine which is why you have to use POE (ester) oil when converting to R-134a. The chlorine will break down PAG oil, thus eventually destroying the compressor due to lack of lubricant. Just use POE oil and this is not a problem.

Desiccants are the other incompatability. XH-5, which is used in R-12 systems, is not compatable with R-134a. This is another mute point as you should replace the drier as a mantainence item anyway. Any new drier will use an XH-7 or XH-9 desiccant. Again - no problem.

The hoses were expected to be incompatible with R-134a's smaller mollecule size, but it has been observed that most hoses were sufficiently sealed up during their operation with R-12 so this is frequently not a problem.

R-134a is less efficient than R-12 hands down. R-134a systems use larger condensors, larger evaporators, and/or other changes to make up for the decrease in efficiency.

The seals in some compressors have been shown to fail with the use of R-134a. Some do; some don't. It's about as simple as that.

The EPA requires different connectors on the service ports for each different refrigerant type. Nothing else is guaranteed to be different/alike.

And specifically regarding 240s, it has been my experience that they perform well with R-134a with nothing more than a drier change.