lexus72

I have '94 es300 that I've owned for two years now with only 137,000miles. The AC has never really worked - it does that typical cold blowing that turns warm after only a few minutes, leading me to believe its the expansion valve (from what I've read). I've read many times over about the expansion valve issue with the 92 -96 models and only now have had the chance (and money) to fix this issue. I purchased a new OEM expansion valve and receiver/drier for the car, and found a reputable-ish mechanic that would install them both plus recharge the system for $125 total.

I brought the car this morning to the shop, and before he did anything, the mechanic told me that the problem is the compressor. He hooked up these guages (sorry, I don't know mechanic lingo) and showed me that the compressor wasn't creating the 30 -40 pressure reading (left guage) and was near 0 for pressure. Mechanic heard the compressor turn on, but says it is the major issue. I do not believe that the mechanic is trying to get me to spend more money - I do believe that he truely thinks the compressor is the issue and not so much the expansion valve. He did replace the drier, but did not replace the expansion valve.

Here are my questions:

1. Is it possible (even reasonable) that its just the expansion valve and not the compressor at all???? Could the low pressure reading be due to a stuck/closed expansion valve? I did ask the mechanic, and he said no.

2. If the compressor is bad, then why am I getting any cold air at all? When its 50 degrees outside, the AC works cold, then blows warm after 20 minutes. If its 80 degrees outside, maybe it blows cold for 2 minutes. I don't want to purchase a used compressor ($100 minimum plus install charge) if I don't need to.

3. solution - ???? (I do not know where these parts are located but, should I ask him to change the expansion valve first and see what happens?) or is the compressor something that you remove to get to the expansion valve?

HELP!!! and Help soon, its getting hotter outside and I have black interior.....and thanks.

GEORGE_JET

First, He told you the compressor was bad before he did anything? Did he even bother to lift the hood before he told you the compressor was bad? Has he seen this car before, or did he have a crystal ball out?? If it starts blowing cold and then goes warm, that is typically the expansion valve. I suppose that you do not recall what the right hand gauge was reading. Typically with a bad expansion you should have a lower than normal low side, and much higher than normal high side. But the fact that he diagnosed a bad compressor before doing any concerns me, take it somewhere else for proper diagnostic testing.

GEORGE_JET

Could you please elaborate on this statement?

"I purchased a new OEM expansion valve and receiver/drier for the car, and found a reputable-ish mechanic that would install them both plus recharge the system for $125 total."

Where did you "Find Him"

lexus72

Yep, I should elaborate: What I meant was that before attempting to just replace the drier and expansion valve for me, he felt it important to test the system first. I didn't mean to imply that he was a "psychic". Because his left guage read LOW (near zero and becoming neg), he said that the compressor was not functioning correctly. Actually, when he first hooked up the guage, the left guage read HIGH HIGH HIGH - then he started the car, the compressor turned on and the left guage fell to near Zero.

I don't know/remember what the right guage had read but i will ask.

lexus72

This mechanic has a shop nearby. He responded to my add on craigslist for HVAC repair. He owns the shop and is giving me a big discount on labor since things have slowed around here - slow economy.

I do believe that overall he is a decent mechanic - BUT as you all know, HVAC work can be complex to interpret.

GEORGE_JET

Ok so with the gauges hook up, and before the compressor starts, both sides should read the same pressure. Once the compressor starts turning, the low side should drop, and the high side should increase. With R134a the low side pressure should be around 30psi ( this will vary with ambient temp and such ). but it is also very important to know what the high side pressure is, which unfortunately you do not know.
So the fact that the pressure starts high, and then dropps to zero can mean that the charge is short, but without knowing the high side, I can not say for sure. With the partial information that you have supplied, it would appear that the compressor is functioning propperly. With that being said, do not get the idea that I am in any way recomending that you buy one a recharge kit from you local auto store and start adding freon. Those kits are very dangerous, if you use one and your system blows up!!

Nuff said. He may be a decent mechanic, but it sounds like he has very little experiance with AC systems, Ask him if he remembers what pressure the high side was.

It sounds like the compressor is working, and it might just be the expansion valve along with a small freon leak.

mmatheny

OK - if your expansion valve is plugged, it WILL suck a vacuum on the low pressure side - how low depends on how plugged the exp valve is. And the high side will run HIGH. I would get the valve changed and recharged - it only takes about 2 cans of freon - and check the pressures again - I'm placing my bet on a plugged exp. valve! I have messed with lots of auto A/Cs - wonder if he has, to make a statement like that! Expecially if the high side was very high, that indicates that the compressor is working. Also, DON'T add ANY extra oil to the system - too much oil will keep it from functioning, and you can almost NEVER get the extra oil out, you have to change out both coils. Just put the freon in.

craiger28

Sorry to jump in this thread but, where is the expansion valve in this particular ES300 specifically located? I am having a similar problem. Thanks

GS4_Fiend

iTrader: (22)

I think you meant "reed valves" not expansion valve. The are two valves in the a/c compressor. You usually don't change the valves but instead, you change the whole compressor. GL!

llcoolpass

Why am I suspecting if it's a defective expansion valve, that this tech didn't even check for it......... and just claims it's the compressor........

CUMan

Inside the car under the dash behind the AC evaporator.

llcoolpass

Best .... Location .... Ever

!

mmatheny

They could have put it on the outside of the firewall like most are! But that would be TOO convenient!

lexus72

Not sure exactly what you meant by your comment?

I reviewed all the searches for an "expansion valve" and the ones for the compressor. I compared other es300 owners symptoms with my car. Since the symptoms seemed to match exactly for the expansion valve, I (a non-mechanic) surmised it to be a faulty expansion valve - the car is 14 years old after all.

So I purchased a new expansion valve from toyota and the reciever drier. I put an add on craigslist for a mechanic to swap out these parts and charge the system. This mechanic responded to do the whole job for $125.

I dropped off the car Saturday and he said that before he did the job, he felt it important to test the pressure of the system. After he checked the pressure, he swapped out the drier and cleaned the system. After that, the low guage still read Zero (not sure about the high). He felt strongly that it was the comporessor. (keep in mind this is not a guy who knows the nuances of a lexus).

I don't understand how the system works. Having said that, I still felt that it was more likely the expansion valve and not the compressor. After all, if it was the compressor that was bad, would I get the 15 minutes of cold air that I do get now before it starts blowing warm?

lexus72

Out of shear curiousity, do you get to the expansion valve from the driver's side or the passenger's side? Not that I would ever even try to do this. i'm just curious.