grivlexus

I've successfully worked around the failed EPR valve on my '92 SC400 with 215k and kickin' you know what. Lexus wanted about $674 for that valve, and even at a discount I could only locate one for $546. A junkyard unit worked for three days before it, too, disintegrated. The rubber just doesn't hold up. (Heck, half the wire connectors on my ignition have all self-destructed.) But the solution is simple. You'll need a 2" square piece of 1/4" aluminum, quality gasket material and hi-temp silicone sealant. Remove the failed valve flange assembly from the valve body, accessible via the four phillips screws. Machine the aluminum to about the same size as the outline where the valve went. Create a plate from the aluminum and drill the four holes necessary to mount the plate to the EPR. The red stuff is Loc-Tite on the four phillips. Cut a gasket to the same size, and when ready, use high-temp silicone to line the area where the gasket will fit on the EPR. I suppose lining both sides wouldn't be a bad thing. Careful not to put too much on - a thin finger glaze will work. Mount the plate and gasket to the EPR, tighten the screws like you would a four-stud tire (cross-wise), and then wait a day for the silicone to cure. Cool your heels. They'll be cooled soon enough by your working AC! The next day, put your vacuum pump on and clear the system out. If the vacuum holds for a half-hour or so, attach your refrigerant tank (I used Forane 409a). Purge your lines, and then introduce the refrigerant. Note: 409a goes in as a liquid - otherwise you can destabilize the gas mix that makes up 409. I loaded about two lbs (I measured it with a Pitney Bowes scale for accuracy). I repaired mine over a month ago, and it's tight as a drum. A note on the EPR: Denso (the manufacturer) has a great little 12 page booklet PDF out there that explains the function of the EPR. http://napabeltshose.com/file_display_common.cfm?thispath=napa_hc%2Fdocuments_module&file=AC_Fundamentals_2-Condensor_Functions.pdf It's job essentially is to prevent frost on the evaporator in cooler, humid climates. I live in south FL and we pretty don't much worry about that. So I jumped it out. This past June saw days here of 96+ and I was just fine. By the way, my SC is black.

I just procured a black SC400 with that retrofit. I live in sunny, hot FLA and to be frank, R134a works, but doesn't have the BTU heat removal capacity of R12. It suffers and would not be acceptable for such a vehicle if delivered (new) from a dealer this way. The car takes about 15-20 mins to cool down the cockpit. It's something you gotta live with. Newer vehicles using R134a have added capacity designed into the R134a AC system to compensate and create the same 3-ton BTU capacity as R12. However, unless you're living in Yuma, AZ, it should provide cooling relief. Sounds like you're undercharged or the expansion valve is not working. I recommend some qualified opinions, but don't jump at the first recommendation. Get a consensus. BTW, I'm dreading summer, it's just around the corner. I may be driving my R12-loaded STS on hot days or when I just have short trips.