AC leak/fix. Anything I'm missing?

funflyer

funflyer

Joined
Jun 26, 2014
Messages
862
Location
Northern Arizona
A few years ago my 01 Taco's A/C started to put out warmer air, and from the bubbles in the sight glass I new there was a leak. At that time, I charged it back up (134a w/dye) and couldn't see any leaks using a UV flashlight. I checked several times over a month and never could find a leak so I figured it must be leaking at the evap core where I couldn't get to with the light. Seemed to hold a charge and work well up until last month. Now I see the dye showing up on the low side schrader valve and also around the compressor clutch, front and back.

I figure I better just shotgun the entire system at this time so I ordered the following parts, along with 134a and PAG46 oil.

evap core
expansion valve
dryer
o-ring seal kit
master seal kit for Denso compressor
schrader valves

I've got the evac and recharge covered, have access to a vacuum pump and manifold gauge set. Anything else I'm overlooking here? I couldn't find anything telling me about any special tools needed for any of the lines or the comp clutch so I'm assuming none are needed?. Thanks.

denso comp.jpg


leak1.jpg


leak2.jpg


leak3.jpg
 
I replace tons of High side hoses on Toyota cars and trucks due to leaks. Also keep in mind that you can't fill or check an R134a system by sight glass. It will always have bubbles in it unless it's overfilled.
 
Thanks guys. Chris, is there a typical area that leaks on the high pressure hoses? Do they crack or leak at the fittings? I did use a gauge set when I charged it last time but don't recall how much refrigerant it took, but once up to proper charge the bubbles cleared up. Matt, I didn't know that about oxidation, and since I don't see any indication of oil around the clutch that's what it could very well be. Since the truck is almost 20 years old I'm going through the entire system so it won't crap out on me again for many years, hopefully.
 
Last edited:
There are specific Car Air Conditioner forum where you can find the quantity required for your Tacoma.
You can Google it.

The hotter the temperature, the better your ability to get the correct amount of refrigerant.
 
Originally Posted by Donald
Are you planning on pulling a vacuum and see how long it holds?


Yes, probably a good idea since I'll have everything in the system apart.
 
Originally Posted by mattd
Just be aware sometimes oxidation can show up green in black light. Honesty I would just replace the valve core and see how long it holds a charge.


I agree . I consider replacing the Shrader valve as preventive maintenance on any / all A/C & HVAC equipment . As a first step when loosing refrigerant .

That alone may reduce the refrigerant loss to a manageable level . And topping off refrigerant is not difficult .

Best of luck ! :)
 
Originally Posted by mpack88
Are you not changing hoses?



Probably will. I didn't find any leaks but I'm thinking it's probably a good idea to change them anyway.
 
Finally had the time to install AC parts and reseal everything yesterday, then recharged the system today. No leaks and AC is back to normal. Glad I decided to reseal the compressor because when I took off the clutch and checked it with the UV light it was glowing green.

comp.jpg
 
Chris142 said:
I replace tons of High side hoses on Toyota cars and trucks due to leaks. Also keep in mind that you can't fill or check an R134a system by sight glass. It will always have bubbles in it unless it's overfilled.
Click to expand...
If the system was designed for R134A then the sight glass will clear when fully charged. This is not the case with blended refrigerants, ie more than on component in a zeotropic blend. Blends often times exhibit temperature glide and fractionation during both evaporation and condensation and the sight glass won't clear. R134A is a single component refrigerant consisting of tetrafluoroethane and is not subject to temperature glide or fractionation. Retrofits from R12 to R134a may not clear the sight glass upon a full charge but that is due to the system not being designed for R134a.
 
JMJNet said:
This is optional but it should help you maximized the seal:
https://www.amazon.com/gp/product/B008HOSQQQ

You can read how to use it.
Somebody suggested it to me when I installed a new compressor in a 04 Sienna.
Click to expand...
I've been using this stuff for years and use it on every seal that I replace except for the sealing washers at the compressor. It also seems to keep the threaded connections from seizing up.
 
Looks like the leak was around the compressor shaft; if you replaced that seal you should be good to go. The Shraeder 'leak' will always be there since some oil comes out whenever you connect to the service port. Sometimes a section of the plumbing next to the valve will also be green where a blast of refrigerant escaped as the service connector was popped off.

R-134a retrofit setups show bubbles in the sight glass because they are not fully charged when filled according to retrofit specs. The reason for that is that running them at full charge would be an overload on an R-12 compressor and likely reduce service life. Retrofits may also show foam in the sight glass; that's due to not completely purging the old oil from the system before recharging.

Torque to operate an R-12 compressor that's been filled to 'no bubbles' or even close with R-134a may be an issue with a small vehicle engine.

The ideal retrofit is buy a complete new system for a later version of that vehicle that's designed for R-134a and mechanically compatible with what you're replacing -- not always easy to spec. Indeed there may not be a compatible later system because BTU for BTU some parts of an R-134 system are larger (at least greater surface area) than the corresponding parts of an R-12 system and a vehicle model that continued through the change over may have gotten either a fits-the-same-space system that may have either comparable or (more likely) rather less capacity, or a physically incompatible system with comparable capacity. The former you can use, the latter probably not.

Note that even though the old plumbing may be perfectly okay and all the major parts fit the vehicle in the same way, the old plumbing may not be usable in a transplant system because of differences in the connections -- incompatible dowel locations, diameters of fittings, and so on. The whole system design is influenced by the refrigerant and oil and in order to keep the oil circulating properly line diameters (and sometimes other things) have to be adjusted in a redesign so you cannot count on mix-and-match. If transplanting an R-134 system to an R-12 car plan to transplant everything, not just the obviously changed parts.

Next best to retrofitting a complete R-134-designed system is to take everything out of the R-12 system, flush the compressor thoroughly with the new oil, flush the evaporator, all the lines and the condenser with a solvent and blow out the excess with shop air, and replace the expansion valve with an R-134a valve. All the o-rings should be replaced with the green R-134 ones. Old R-12 hoses generally don't have to be replaced: They're impregnated with oil and that seems to protect them.

Of course many people just remove (hopefully recycle) the old refrigerant, maybe drain the compressor oil, add some R-134 oil, shoot in some R-134a, and go. Those people get cooling, may or may not have bubbles, and will definitely have foam from the mix of oils and a refrigerant that's incompatible with the old mineral oil that's still in there.

There's no substitute for finding and following manufacturer's specs for what you want to do.
 
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