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New and need help. Cool then warm and low vacuum.

Jag987 on Tue June 18, 2013 2:17 AM User is offline

Year: 1994
Make: Toyota
Model: 4Runner
Engine Size: 22re
Refrigerant Type: R134a

Great info here! I have already learned lots, but not quite what I am looking for.

Before I ever saw it, "mechanic in a can" stop leak was added.

Ok, here is what I have. when the AC is first turned on, it blows cold. Like an idiot, I did not record pressures because everything looked fine and I was not sure what they were complaining about. after about 10 minutes, the low side slowly started to drop for about 20 seconds and got down to about 15psi. Then it jumped down and into vacuum. the compressor never shut off. I have two thoughts on it, first is the stop leak is plugging the expansion valve, but then I would think it would just be plugged and never work at all. My other thought is that there is moisture in the system. The owner does not have much money, so I am doing this mostly as a favor. I don't want to just start throwing parts at it.

Thanks for the help and the great forum!

I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

mk378 on Tue June 18, 2013 8:17 AM User is offline

It certainly seems to be a TXV issue. Before you go any further you need to find out what kind of stop leak was used. The "super" kind hardens when exposed to air, thus you can't open the system without having it all harden and ruin all the parts. So total system replacement is the only option. It is sold in a separate small can. The other kind of "stop leak" that is supposed to just swell the seals is usually included in a 12 oz can of refrigerant. That kind doesn't cause as much damage, though it rarely stops leaks either.

NickD on Tue June 18, 2013 10:49 AM User is offline

With these systems, as long as the high side pressure is between 40 and 430 psi and the evaporator temperature is above 33*F, the compressor will run. On some of these systems, don't know until I look, may also have a speed sensor on the compressor if that doesn't match the crank speed, compressor will not come on at all. But this is assuming the electrical system is okay.

Start off by using something like a remote starter switch to directly engage the compressor with manifold gauges attached to look at pressures. If bad, a real quick means to shut it down. Do an electronic leak test, and whatever else is necessary to get this part of the system working properly, then dig into the electrical system where you can even find more problems.

Never ever would I add sealer to a system, doesn't do any good. Can run into two different kinds of problems with an old vehicle, either not worth repairing properly or lack of funds. Here the only solution is to roll down a window. Also even more problems with R-134a with concerns about sludge and acid problems, they are not making it any easier.

Jag987 on Tue June 18, 2013 10:53 PM User is offline

Interesting, I have never heard of a kind of stop leak the hardens when exposed to air. But that would explain how it could seal leaks in metal such as a condenser. There is no way for me to find out what was added. I would hope that anyone silly enough to add stop leak would be smart enough to to add the kind that would harden. Could the system be flushed before it did harden if that was the case? Flushing the compressor just seems like a bad idea.

There was not a speed sensor on the compressor, and I did not see any extra wires going to it either.I do not think there are any electrical problems at this time. "not worth repairing properly or lack of funds" I would agree with both of these statements. But I am wrong. They had the engine replaced less that a year ago so they think it is worth keeping and must have the funds.

The TXV and drier seem to be in a section of the HVAC duct work that will easily come out (the glove box is already missing), so I think I am going to evacuate, flush lines, replace parts and see what happens. Yes, I will pull a good vacuum for a couple of hours to make sure all the moisture is boiled out. I think my biggest concern now is what was leaking and will it come back after I fix this problem. The stop leak worked, it was added weeks ago and the system still had good pressure and was working.

Thanks for the knowledge and ideas.

I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

iceman2555 on Wed June 19, 2013 8:52 AM User is offlineView users profile

If this system has had stop leak added to the system, a strong suggestion would be to replace the entire system. The chances of flushing and cleaning this system are so remote....residuals remaining in the system will simply migrate thru the system and result in possible restrictions. Restrictions lead to reduction of refrigerant and lubricant flow...the result being a failed system once more.
Bite the bullet.....spend the it and enjoy the cooling.
Stop leak does not simply harden when exposed to air as it exits the lead hardens inside the system when exposed to moisture and possible air contamination. Often this material becomes a semi solid gel like material within the system. Would be great is the stop leak mfger's would warranty all the products that their products cause to fail.

The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

NickD on Wed June 19, 2013 11:56 AM User is offline

So far, haven't heard of any liability suits against these companies. That is how its done nowadays with a zero FTC. But the burden of proof will be upon your shoulders and that could be difficult if not expensive.

Can save a bundle by doing it yourself and know its done right with even buying all the necessary equipment, then you have it for the next time, and will be a next time.

Ha, with an old system a lot easier to cut it out than to try to mess with badly corroded fittings.

Talk to Tim.

Jag987 on Wed July 03, 2013 10:38 PM User is offline

So I tore into it. Flushed the lines, condenser and evaporator. Nothing looked at all like it had stop leak or anything besides oil in it. Installed a new valve, drier and oil. Pulled vacuum for about 5 minutes then let it set for about 45....and the gauges did not move. So I let the vacuum pump run for about 30 minutes then let it set for another 45 and it still held. So I filled it up and let the truck run while I re-installed the grill and bumper (had to come off to get to the drier). thermometer showed just under 40* in the drivers side vent...with the windows down and about 90* outside, but it was in the shade. That was 5 days ago and I have not heard back from them yet so I am sure all is well. Thanks guys!

I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

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