I replaced my compressor while doing the timing belt last fall. And just filled it with nitrogen for the winter. Now that Spring has arrived, I needed to complete this project. I had a friend helping me, an hvac tech, who has all the knowledge and equipment that comes in handy on these kinds of jobs. I had him helping me flush, evacuate, and fill up the A/C system. After reading this forum I had pretty much planned on leaving the expansion valve alone. Then while putting together a plan, he looked at the new expansion valve, that was included with the new compressor I purchased. And said that the old one would have to be removed and the lines flushed at that spot to effectively clean out the evaporator. A job I wasn’t looking forward to, if it meant pulling the dash. However we started looking under the dash, and found just enough room to remove the old expansion valve. It was by a couple big wire harnesses, that needed to be unplugged and positioned out of the way. Then I just had to remove a bunch of insulation tape to access a couple Allen bolts holding it on. Once I had it out, we attached a few feet of power steering hose, that I had left over from another project, and attached my A/C flush bottle, and began cleaning out the evaporator. The whole deal, R&R the expansion valve and flushing the evaporator, only added about 90 minutes to the rest of the job. If your doing this job, and want to do it right, don’t let replacing the expansion valve intimate u. Spending the money on a new compressor and condenser is a big investment. It’s worth doing this part, to know nothing is waiting to destroy your new compressor.

Thanks for a great write up. Do you have a link for your evaporator replacement? I have a very small leak in the evaporator that will require serious disassembly to reach. If you have directions of the correct order it would be really helpful. I figured out how to get into the flow dampers but the evaporator is a while new level of disassembly.

Addison

Ps I have a 2000 GS400

You’ll find a full write up on replacing the evaporator core in the “do-it-yourself” section.
If it’s a “small leak” you might consider trying some stop leak before anything else. I normally don’t suggest using those types of product, but they actually have a pretty good track record for working on the AC system. If your car is still holding a little charge, u might be able to get it working again with just some stop leak and refilling the refrigerant, If it’s already empty, you’ll have to evacuate it before recharging it. Good luck

Thanks for the suggestion. My 190K mile AC is losing about 1 12oz can every 2-3 weeks. I have done the full leak check with dye and with an electronic sniffer and the only place where I get a hit is inside the car at the main ducts. When I turn the ignition switch to start the fan I get a brief hit on my sniffer as the air blows out. Once the fan is turning, even on its lowest setting I can’t get any reading. Similarly I have not seen any signs of dye under the car from the evaporator drain.

I have avoided adding any leak stop type products because I was concerned about the possible effects on the compressor which touch wood seems to be fine. Do you have a recommendation as to the type of leak stop to use? I am familiar with marine refrigeration and the manufacturers of 12v compressors are dead against the use of any additives in the refrigerant other than PAG oil and leak detecting dye.

Thanks again for your great write ups.

I have never actually used any, so I can’t help as far as a specific brand recommendation. I do know that your going to have some options about what method to add it to the system. The easiest one in most cases, will be to find a refrigerant with a stop leak added to it. Unless you don’t mind opening up the system. I understand it is basically like an oil that will find it’s way to the leak and can form a barrier. It’s supposed to be very different from the way fix-a-flat or radiator stop leak become hard when exposed to air. So you shouldn’t have any problems if you ever have a shop recover the refrigerant or anything like that.