again a/c got me crazy

[Nonobeez]

First order of business for most of us is get the fan clutch sorted out/upgraded. Get a new blue one from Rock Auto or Amazon. Replace the silicone fluid with 20-30,000 CST silicone and then go from there. Search on this forum for lots of info on this. John

I already changed the silicone fluid, did not help my situation, others may have different results.

There are 2 ways to look at the problem, and probably only one is correct.

1. Your overheating problem is causing A/C problems... OR

2. Your A/C problems is causing overheating problems.

I know my vehicle I have excellent A/C cooling in the driveway. But even in the morning when it is cool and motor cold, the pressures are not OK. I drive the 12 miles to work and the A/C quits and sometimes the vehicle gets hot and the inaccurate temp gauge goes up up up.

As I mentioned above, low low pressure readings are due to an obstruction. I will add that too much oil may have accumulated due to occasional recharges from refrigerant that also has extra oil. I may have also sucked in some air and now the moisture is freezing and plugging the Expansion valve... or the expansion valve itself is bad. My wife did complain of a foul odor when the A/C failed, which may be due to a leaking expansion valve bulb (Ammonia?)

I am sure changing the Expansion valve and dryer along with maybe a flush, evacuation and recharge will fix the issue.

 

[inkpot]

I already changed the silicone fluid, did not help my situation, others may have different results.

There are 2 ways to look at the problem, and probably only one is correct.

1. Your overheating problem is causing A/C problems... OR

2. Your A/C problems is causing overheating problems.

I know my vehicle I have excellent A/C cooling in the driveway. But even in the morning when it is cool and motor cold, the pressures are not OK. I drive the 12 miles to work and the A/C quits and sometimes the vehicle gets hot and the inaccurate temp gauge goes up up up.

As I mentioned above, low low pressure readings are due to an obstruction. I will add that too much oil may have accumulated due to occasional recharges from refrigerant that also has extra oil. I may have also sucked in some air and now the moisture is freezing and plugging the Expansion valve... or the expansion valve itself is bad. My wife did complain of a foul odor when the A/C failed, which may be due to a leaking expansion valve bulb (Ammonia?)

I am sure changing the Expansion valve and dryer along with maybe a flush, evacuation and recharge will fix the issue.

My response was for the Original Poster. In post #8 he said that he had an Autozone aftermarket clutch. OEM is the only way to go for fan clutches. John

 

[jeepkiller]

ok ..finally got back to the lx450 a/c numbers are ....low #35 high #400 so i am thinking expansion valve but since i have to evac system any way i released some on the high side and got it down to 275 but then the low side went to 10 should i evac the whole system and try to recharge before i dig into the valve which i here is behind the glove box ...i got a couple mixed answer from some people i know they said if the low side was low and high side high it is the valve ..but the low side was normal and high was high. any help appreciated...1997 lx450 no mechanical modes except for the new electric fan which is 3000 cfm

 

[Nonobeez]

Did a partial recovery (left positive pressure)

Replaced Expansion valve and Dryer (Denso from Amazon, $65)

Charged to 100 PSI with Nitrogen for 15-20 min... good.

Pulled vacuum (w/ engine up to operating temp) and held it for 15-20 min... good.

Factory charged to about 1.8 lbs (plus 3 oz in lines).

All GOOD NOW!!! no more low pressure on the low side. I did find a little bit of oil in the expansion valve and the pigtail on the TXV was a bit corroded.

 

[Jungle80farmer]

Mine was doing the same thing. Ended up being the expansion valve closing as soon as I started driving.

 

[Blue66tang]

Your evaporator could be freezing if the pump is not cycling properly. I had a vehicle do this once.

 

[flintknapper]

ok ..finally got back to the lx450 a/c numbers are ....low #35 high #400 so i am thinking expansion valve but since i have to evac system any way i released some on the high side and got it down to 275 but then the low side went to 10 should i evac the whole system and try to recharge before i dig into the valve which i here is behind the glove box ...i got a couple mixed answer from some people i know they said if the low side was low and high side high it is the valve ..but the low side was normal and high was high. any help appreciated...1997 lx450 no mechanical modes except for the new electric fan which is 3000 cfm

You have an obstruction of some type or the expansion valve has failed. The TXV is on the evaporator, the evaporator is housed in a plastic box behind your glove box.

I would evac the system, flush it, install a new TXV and drier, add the appropriate amount of oil to your drier, condenser and evaporator (to replace what was lost). Pump it down and recharge with 1.8 lbs 134a