I've got a 95 240 and went to a family friend to have my air looked at and he said I needed to change my expansion valve. I think he said at the time he was reading 70 low and 110 high. I went ahead and changed the expansion valve and the receiver drier. He hooked up a vacuum for almost and hour and it held at -30 afterwards. He added some freon and said it was kind of high still i think i saw 60 low and 200 high. He said to drive the car around and perhaps the valve has to "break in". A/C seems cooler now but before it used to be really cold. Also, on my way home from the shop at one point the air got hot and the car started to bog every 10 seconds cruising at 60mph, it only happened for a few minutes and then went away. Anyone have any input on this situation? Why was it bogging and what could be causing low side to be a little high still?

 

figured out the bogging is the a/c kicking on and off really fast, was sitting at the traffic light and every 5 seconds it was kicking on and off. Guess it's time to change the compressor

 

if its cycling that often, it sounds like its undercharged.
also there is no reason to vacuum the system for that long, it can actually cause damage.
half hour tops.

worst case, replace the compressor, id replace the dryer again, just because its only 15$ or so. and make sure its charged correctly.

 

My maxima compressor was doing the same thing, it would shut on and off rapidly. the compressor has to have the right amount of freon for it to activate and cycle, maybe he to much freon, and theres way to much pressure in the system. Might just want to check that out before you buy a new compressor.

 

theres always a low pressure switch, that if the system is low will make it work like that, cycling on and off. alot of cars also have a high pressure switch that will do the same thing.

 

Hello there, I just read your post this morning and i also read that you actually changed the expansion valve. I was thinking if you can possibly help me with this one, i am searching the net for a procedure. I know this was almost ages ago but im still hoping you can still help me on this one.