AC Tech? Help!

[NevadaSTi]

I just picked up a Toyota 4Runner from a buddy of mine. Its a 1994 4x4 V6 with an auto-tranny. Here is the issue with the AC. It works, but then sometimes it doesn't work. It's would seam that the clutch is not engaging. When I turn on the AC the clutch will try to engage the compressor pump, but it won't turn it over. The compressor will turn over, albiet very slow and more or less in a random manor.

I was checking a site on AC fixes, and they made a statement that most AC systems have a low refrigerant level safety system that prevents the pump from working. I am assuming this is to prevent the compressor pump from burning out.

Make sure the compressor is turning. Start the car, turn on the AC and look under the hood. The AC compressor is generally a pumplike thing off to one side with large rubber and steel hoses going to it. It will not have a filler cap on it, but will often have one or two things that look like the valve stems on a bike tire. The pulley on the front of the compressor exists as an outer pulley and an inner hub which turns when an electric clutch is engaged. If the AC is on and the blower is on, but the center of the pulley is not turning, then the compressor's clutch is not engaging. This could be a bad fuse, a wiring problem, a broken AC switch in your dash, or the system could be low on refrigerant (most systems have a low-pressure safety cutout that will disable the compressor if there isn't enough refrigerant in the system).

http://www.wikihow.com/Fix-Your-Car's-Air-Conditioner

So this makes me wonder if either the system is low on refrigerant, or if the clutch on the compressor pump is just worn out?

Anybody?

[NevadaSTi]

Oh yeah, to the best of my knowledge the system is still using R12. I was unable to locate any stickers or plaque that state the system was upgraded to r-134a.

[MPREZIV]

Sounds like the clutch is worn out. The low pressure system you mentioned will cause the clutch to not engauge at all, not intermittantly. If it's trying to grab, but just doesn't seem to hold well, I'd say it's likely the clutch is just plain worn. Replace it...

[NevadaSTi]

How do I replace the clutch? Or do I replace the whole pump?

Napa has the clutch, its only $195!!!

[MPREZIV]

Yeah, you can just unbolt the clutch hub from the front, but often times they need a puller to get them off even with the hardware removed. Can't tell you for sure how yours is set up tho.

[Dean]

Originally Posted by NevadaSTi

How do I replace the clutch? Or do I replace the whole pump?

Napa has the clutch, its only $195!!!

You should be able to get compressor and clutch for <195 on eBay... Scott wouldn't, but the one I got and Cory put on my F150 is doing fine.

[MPREZIV]

Who put on your F-150?

[Dean]

Originally Posted by MPREZIV

Who put on your F-150?

Fixed.

[MPREZIV]

Nice! I was just remembering the F*ing FORD thread I started the day before, when the slave cylinder lost all it's fluid on me...

[100_Percent_Juice]

The compressor/clutch went out on my 89 f150 also. I went to reno auto wrecker and picked one up for $50 I think. It wasn't too hard to install.

[NevadaSTi]

I found one for $115 at kragen. It looks as though it has a bolt that you remove. More than likely it also has to have a three jaw puller to remove it.

[Kevin M]

1994 model year should be R-134a shouldn't it?

[NevadaSTi]

It might, but I thought it was 97 and up.

[Kevin M]

That's OBDII.

[100_Percent_Juice]

Originally Posted by NevadaSTi

I found one for $115 at kragen. It looks as though it has a bolt that you remove. More than likely it also has to have a three jaw puller to remove it.

I am pretty sure kragen will also have the rental tools to do that.

[NevadaSTi]

I guess I should go buy a toyota manual, unless someone has one already they wouldn't mind loaning out?

[AtomicLabMonkey]

Just install a swamp cooler in it.

[NevadaSTi]

http://cosprings.craigslist.org/clt/376037310.html

You mean, one of these?

[rubberbiscuitt]

*you can jump the clutch pos wire to your alternator to continuously cycle the compressor. always on? clutch is less likely to be bad. still unfrequent off? yes clutch bad.
*go to walmart and get the can of refer and a guage for $20. most likely it'll suck up all the refer, you'll get cold air and a properly cycling a/c and then you'll be done.
*if it doesn't take the refer then you'll be out $20 then get someone qulified to diagnose the system other than an e-tard that pretends they know a thing or two.

94 is the raged edge of r12 or r134a. 95+ is for sure r134a.

[NevadaSTi]

I found a Toyota service tech. article online that states 1993 4Runners had R12, and 1994 and up 4Runners have r134a.

So, I guess all I have to do is get the clutch at Kragen or someplace and swap out clutches.

[Kevin M]

I recommend the jumper procedure first. I agree it is probably the clutch, but that's a simple and practically free troubleshooter that may save you time, effort and money.

[NevadaSTi]

I am gonna do that. The clutch isn't even engaging anymore. Or it is, and just not holding. It worked yesterday at lunch, but if I rev the motor up too much, it wouldn't stay engaged. But if I turned it off at idle, and then turned it back on it would work again. But last night it wouldn't even do that anymore.

[Dean]

Originally Posted by NevadaSTi

I am gonna do that. The clutch isn't even engaging anymore. Or it is, and just not holding. It worked yesterday at lunch, but if I rev the motor up too much, it wouldn't stay engaged. But if I turned it off at idle, and then turned it back on it would work again. But last night it wouldn't even do that anymore.

Be aware that if the compressor bearings are going or something similar, that may be why the clutch is failing. If it is old enough to burn up a clutch, it may not be a bad idea replacing the whole thing. Mine was on a '94 F-150 with 85K miles or so and the compressor was the problem.

If you go that way, make sure you get a drier and O-Rings.

[rubberbiscuitt]

i still think that it's just a low refer charge. the compressor shouldn't cycle a bunch at higher revs because it compresses more.

dean good point about the bearings and stuff. refer has oil or otherwise lubricant in it. if it's low on refer, then it's low on lube and bearings are in danger.

[rubberbiscuitt]

oh yeah and a simple way to tell what type of refer is the fittings. r12 looks like a tire valve(schredder) on steroids. r134a looks like a stubby shop air chuck(much larger than r12). and hope that the system wasn't retrofitted.