I recently picked up a 2000 ls400. Just did a timing belt waterpump and all that jazz. The ac wasn't working becuase the wiring was tore off the comp clutch. I got that fixed and began charging the system. It took about 3 cans and the compressor would run about every 30 seconds for 1 second. I hot wired the MG CLT becuase ive had to do that on other cars and trucks. It blew the "discharge" hose almost immediately. The guages read EXTREMELY HIGH on the high side. Im talking 700psi. Im completly new to lexus and completly a noob at A/C. my guess is expansion valve. So I wanted to replace the drier, expansion valve, and discharge hose. Is this the right assumption. I've owned the car for a week and have spent like over 5k so I'd like to keep it pretty cheap. Thanks in advance.

 

yikes about hot wiring the compressor? if you are new, i would not have done that for risk for injury but glad you are alright to tell us about the tale.

AC is a specialized skill where many things can go wrong. i try to stay away from those cans you get from the auto store since they only bandaid the solution which is usually much larger. better to take it to an AC specialist who can diagnose it. you'll likely spend too much shotgunning the solution yourself.

 

AC is not filled by volume, like those cans you buy at the store. It is filled by weight, which can only properly be measured by a machine. I would recommend disconnecting the AC compressor, do not run it, and take it to a shop that does AC work. I DIY anything and everything, but AC is something you need the pro's for.

 

Exactly!!!!! Out of everything I've done on vehicles over the many, many years, I don't touch A/C work. With you being "new" to A/C, you shouldn't be trying stuff like this. The only time I've done something with A/C is I tried recharging it with a store bought can. (with gauges) Everything seemed to be going good and I was getting happy, then all of a sudden the can blew off the A/C line, outta my hand and put a 3" round dent in the hood about an inch deep. Freon everywhere, covered the whole engine bay. Damn good thing my head was off to the side or I wouldn't be writing this now.
You say you used 3 cans, you had 700psi? That sure don't sound right to me. Take it to the pros.

 

Me either.

 

Do yourself a favour, if you want to ensure your $5K you've already spent is'nt wasted, then get your AC sorted professionally! messing with the pressures' and complexity involved can be and is dangerous. I suspect the system will require a full purge/evacuation and then fill/re-pressuring.

 

I understand everyone’s concern. I’ve never had a car in a shop and I’ve done everything from soldering ecu’s and building wiring harnesses to building motors. As long as im upright that’s the way it will be. I’ll be changing the expansion valve, drier, and the discharge tube. I’ll be back with updates in case someone winds up with the same issues and situation.

 

I understand where you are coming from LSforhunet. I DIY 9 times out of 10. I do however agree with the others here that it is pretty smart to let the experts deal with the AC.
My 1995 only needed a refill. 40% was left and it was really weak. Probably 10-15 years since last refill. Now AC works very well again and they fixed it fast for a modest charge.

 

I do my own AC work and the necessary equipment even to do simple repairs isn't cheap. You find out pretty quick that there are no cheap shortcuts to get a system properly repaired and working efficiently.

Absolute minimum are a gauge set, vacuum pump, leak sniffer (or an old school propane sniffer) and a flushing tool (those can and hose deals leave a lot to be desired).

Don't ever introduce any kind of stop leak in your system.

This is a good place for info and Q&A: https://autoacforum.com/index.php

 

Best practice when replacing AC Compressor, pressure/return lines, dryer, evaporator, etc. is to evacuate the system... this requires professional equipment to avoid venting into atmosphere...

Recharging the system requires use of correct type, amount and mix of compressor oil.

This is something I prefer dealer to manage.

In fact, if necessary to validate Denso aftermarket compressor warranty requires proof that dryer was replaced and certified mechanic performed refill of freon/oil mix.

 

Jesus christ, 3 cans, did you follow any service procedures. The AC refrigerant capacity is 1.52 lbs, most of the store bought cans are 1 lb each. You most likely severely overcharged the system, thats why your pressures are so high and your compressor is only running in 1 second bursts. High side pressure should be around 150-190 psi depending on ambient temperature and low side pressure should be around 30-50 psi depending on ambient temperature. And those store bought cans are not a proper way of servicing the system. The ac should be recovered, system put in a vacuum for 10-15 minutes and a 5 minute vacuum test performed, (to test if there are leaks in the system). Then the system is to be recharged with the proper amount of refrigerant. Also to be noted, any time the system is serviced, any component replace or just "recharged", the ac drier is supposed to be replaced, (Absorbs all the moisture in the refrigerant). As far as the wiring is concerned, take it to a pro, the ac should not be "hot wired". If the system was empty, there is a leak. Refrigerant doesn't just disappear.