1994 A/c blowing out the expansion valve

[porreca1]

That is actually a low-side pressure relief valve. My Ranger had issues with that valve also (factory R-134a), so maybe this is a common issue (I'm not even sure what it's purpose is... the low side is never pressurized by the compressor, it's pressure actually drops during operation. My BII has no such valve at all on it's low side).

My issue was when running the engine in hot ambient temps with the A/C OFF (especially at high elevation), that valve would release the freon to the atmosphere (defective in that it's pressure point was set too low). Unfortunately it didn't become obvious this is what was happening until after the warranty ran out I noticed the A/C was no longer cooling as well.
While fixing/recharging the system I blocked it off entirely (leaving the high-side relief valve & cutout switch in place for obvious reasons). Since then I've not had any further issues with it.

My suggestion would be to do the same, replace the orifice tube with a new one (they're $10, replace it), replace the accumulator (new desiccant), replace all the o-rings in the stsyem, then button it up and do a full evacuation and recharge on it (22 oz R-134a and 7 oz PAG46 oil IIRC).
Your old orifice tube looks relatively free of debris, however watch out for presence of thick black sludge (Black Death) when you pull the lines off the compressor and condenser for your o-rings. Black Death = replacement of those latter two items is required as well (in addition to replacing the discharge line too if it's got one of those muffler thingies on it).

Hope that helps.

Helps a lot, thanks. I will replace both and grab an o-ring pack. I assume the accumulator is where most of the oil is, so will need the full 7 oz listed above. Did you just get a bolt of the same size and slap an o-ring on it to plug the low pressure relief?

Thanks again.

 

[4x4junkie]

Helps a lot, thanks. I will replace both and grab an o-ring pack. I assume the accumulator is where most of the oil is, so will need the full 7 oz listed above. Did you just get a bolt of the same size and slap an o-ring on it to plug the low pressure relief?

Thanks again.

It was 10 or 12 years ago, I'd have to go look at what exactly I did again...

I don't think a bolt with an o-ring would work though unless you were to machine a groove under the bolt head surface to capture the O-ring in, pressure might blow the o-ring out otherwise. A bolt and a soft copper washer might work though (like those used on a brake caliper).


The compressor will need around 3 oz of oil in it, the rest can go in the accumulator or wherever.

 

[porreca1]

That is actually a low-side pressure relief valve. My Ranger had issues with that valve also (factory R-134a), so maybe this is a common issue (I'm not even sure what it's purpose is... the low side is never pressurized by the compressor, it's pressure actually drops during operation. My BII has no such valve at all on it's low side).

My issue was when running the engine in hot ambient temps with the A/C OFF (especially at high elevation), that valve would release the freon to the atmosphere (defective in that it's pressure point was set too low). Unfortunately it didn't become obvious this is what was happening until after the warranty ran out I noticed the A/C was no longer cooling as well.
While fixing/recharging the system I blocked it off entirely (leaving the high-side relief valve & cutout switch in place for obvious reasons). Since then I've not had any further issues with it.

My suggestion would be to do the same, replace the orifice tube with a new one (they're $10, replace it), replace the accumulator (new desiccant), replace all the o-rings in the stsyem, then button it up and do a full evacuation and recharge on it (22 oz R-134a and 7 oz PAG46 oil IIRC).
Your old orifice tube looks relatively free of debris, however watch out for presence of thick black sludge (Black Death) when you pull the lines off the compressor and condenser for your o-rings. Black Death = replacement of those latter two items is required as well (in addition to replacing the discharge line too if it's got one of those muffler thingies on it).

Hope that helps.

Worked! ....Thanks for the help!

 

[4x4junkie]

No prob

Glad to hear you got it working.

 

[shane96ranger]

Quick questions.... how do you introduce the oil into the system? And does the whole system use 7 ounces total?

 

[adsm08]

Assuming an AC machine is not available I would pour 2 to3 ounces into the large port on the compressor, spin it by hand two or three times, and then our the rest into the accumulator.

An AC machine would just inject it into the low side service port.

The total capacity of the system is what ever is printed on the label.

 

[shane96ranger]

Assuming an AC machine is not available I would pour 2 to3 ounces into the large port on the compressor, spin it by hand two or three times, and then our the rest into the accumulator.

An AC machine would just inject it into the low side service port.

The total capacity of the system is what ever is printed on the label.

Thanks! As you may remember, I am getting ready to do this exercise. I had to buy my daughters school uniforms and I've got to register the truck this month, or I would be done already.

Posting from the Galaxy.