Eli Singh

Hello there! I just bought a 1992 4runner SR5 with a little over 367,000 miles on it as a project, and living out here in AZ, air conditioning is a must. The AC didnt work when I bought it, so we started diagnosing the problem and it looks like the compressor clutch is bad. It has already been converted to r134a. I am going to change the compressor and receiver dryer, but I was wondering is there anything else I need to change? Also, would a Denso compressor be the best bet or could/should I go aftermarket? Thanks in advance!

wyoming9

iTrader: (1)

Why change the compressor if it is only the clutch unless you want to..

How did you figure it was the clutch ??

Does the system hold vacuum??

scope103

Here's everything I know about A/C: https://www.yotatech.com/forums/f116...-r134a-284801/

The clutch CAN be replaced separately, which I would guess is a much simpler task than replacing the whole compressor.

Eli Singh

From all the research I’ve done doing the clutch will actually be a harder job, I went ahead and got a new compressor, receiver drier, expansion valve, and some o rings and gaskets, since the r134a conversion has already been done I don’t need those parts. Since I just bought the car I am going to just fix up every piece as well as I can, and replace as much as I can afford 😅 the parts come in in a couple days, I’ll post how the swap goes on this thread by the end of next weekend!

Eli Singh

also scope, is there a difference in types of O rings? I ordered a set off rock auto, but I’m now wondering if they are different with a r134 converted system

wyoming9

iTrader: (1)

I can change a AC compressor clutch in about 30 minutes

I hope your new compressor comes with the clutch some do some don`t .

If you can swap a compressor that fast you are my new Hero

No doubt working in a Auto Shop that only does AC work

So to my Question does your system hold a vacuum??

Eli Singh

scope103

What are "those parts"? At one time, it was believed that the R134a lubricant (PAG 45) was incompatible with the o-rings used with mineral oil. So it was often recommended to change all the o-rings. But since you're replacing all the o-rings (all of them, right?), you don't care (since you can't sell a vehicle car with R12 for the past 24 years, I can't imagine how you could even find the "wrong" o-rings for R134a.)

How do you plan to look for your leak? Releasing any refrigerant into the air will, eventually, kill us all.

Here's the manual for changing the A/C Compressor Clutch. http://web.archive.org/web/201102052...12compress.pdf And, guess what, it includes the diagnostics so that you can tell IN ADVANCE if changing the clutch is what you should do.

Eli Singh

Eli Singh

scope103

Well, you do have a diagnostics problem. You know the clutch isn't closing with power applied, but that's all you know. When you replace the clutch, you might find the compressor is frozen, or just not pumping. You DO know that the system won't hold a vacuum, but you don't (I presume) know where. If it's in the cooling unit (condensor), you're going to have to pull that out, and with it out you definitely will replace the TXV. As I noted, the warranty on your new compressor is almost certainly no good if you DON'T replace the TXV (and flush the system).

If it were mine (and I didn't have the advice of a top-notch Porsche mechanic), I'd first pressurize the system with air to find the leak. Then you'll know (more about) which parts need to be replaced. What I wouldn't do is charge the system with R134a with the plan to just let it squeech out into the atmosphere as a substitute.

mholme

You're dealing with a 26 year old vehicle with unknown history of the AC system. It failed for a reason and you don't know what it pushed, pulled, sucked into every component. You also don't know what, if any oil is left in the compressor, so you need to pull it anyway. Even with a new compressor, you need to verify how much oil is in it. My new DENSO compressor came with about half of the specified oil charge.

If it were me, and it was not too long ago, I'd want to make sure everything is clean, debris and leak free before trying to make it cool. Most of the R134a "conversions" were and are, nothing more than putting fittings on the service ports of R12 hoses to make them take a charge with newer service equipment. So without knowing the history of the system other than that the compressor clutch doesn't engage and it doesn't hold vacuum, be prepared to do more than just replace the compressor/clutch, drier, o-rings and TXV. You may need new or rebuilt hoses too. I did, even though I bought used hoses off a vehicle that had already been converted. Remember that these conversions were being done decades ago and hoses don't last forever, especially with a gas they weren't designed for.

And scope103 is right about the warranty on a new compressor. You have to show proof of flushing the system and replacing the TXV in the evaporator box for them to honor a failed compressor. So just do it once and do it right. It's not that hard to get these systems working well.