vwclevenger

1992 SC400, 80K mi, Metalic Desert Beige, tan interior; did secumb to the need for more horses and installed an Ingen CAI - what a great highway cruiser (28.6 mpg with the Ingen)

Three cheers for the synthetic oil, the only issue that I am aware of is that due to smaller molecule size will find it's way through areas that previously didn't leak - generally, this is a non-issue; I have converted every one of my oil users to synthetic without a problem. And, yes, the synthetic will result in lower HC readings; Castrol even makes a "senior" synthetic blend for older, high mileage cars. As for additives in the gas (octane booster and injector cleaner), it has never been an issue. Plug wires though, with the new 100K plugs running around wear out also and break down; this is especially true if the wires are "bundled" closely and you end up with cross talk and random plug firing, I change mine every 50K just because of the almost year round heat in SoCal that jacks up the underhood temps. Here's what my '92 SC400 blew this week: 15 MPH test: CO2 (14.7) O2 (0) HC (73 max, 2 meas) CO (0.49 max, 0.04 meas) NO (530 max, 65 meas) 25 MPH test: CO2 (14.7) O2 (0) HC (56 max, 0 meas) CO (0.39 max, 0.03 meas) NO (487 max, 127 meas) Test conditions: Pump Hi-Test gas, 104 octane booster in tank, injector cleaner in tank, fresh synthetic oil and filter, K&N filter The passed it with an Airbag warning light on so don't worry about the lights you mentioned, although tauted as a safety and emissions test, they are really only concerned about what comes out of the tailpipe. The grade of oil that you need is more of a function of how you drive and the driving environment (open road vs stop & go, towing a trailer vs nothing in the trunk and one person on board, etc), a good mechanic or oil manufacturer's web site can walk you thru what is best for your car and driving needs.

I don't drive new cars ('92 SC400, '86 MBZ 560SL, '00 MBZ 320CLK and '02 MBZ ML500) so I go thru the same angst every year in San Diego. I have it down to a standard routine for about $30 at your local parts store: Tank of gas before taking it in: a double dose of injector cleaner (works best if you do start/stop driving giving it a chance to soak), a dose of octane booster, a dose of water absorber and a spray can of mass air sensor mesh cleaner (again, I pause for 10 minutes to let it soak with the engine off and then finish with the rest of the can). I'll assume that you do the routine stuff: fresh synthetic oil and filter, new air filter (the high flow filters get more air in for more complete combustion. Plugs AND wires if they are needed for routine servicing (if they are due within the next 5-15K miles, you're gonna do it anyway so go ahead and do it early, it can't hurt. O2 sensors can be an issue, their response time degrades with time and use but the smog test is pretty benign so they should settle down for the steady state testing. Tank of gas for testing: hi-test, dose of octane booster, dose of injector cleaner and make sure it is hot, hot, hot when you take it in. Just got the two older ones tested and passed with flying colors as ususal.

Hi guys/gals. I have noticed a recurring theme in perusing the various forums - tons of dyi requests for help and/or technical data related to whatever model they own. I went off in pursuit of a shop manual for a 1992 SC400 and found a download site for $ 9.99 per shop manual (mine is over 4000 pages of tech data, error codes and repair/replace sequences as well as trouble-shooting flow charts based on symptoms. For anybody who is interested, it is downloadable from Tradebit.com. I downloaded it and then made a CD backup and loaded it on my garage laptop (ancient technology that was replaced and found a new home as an electronic manual server in the garage).

As of today (1/28/2012), the link : http://lexus.sewellparts.com/accessories-catalog/interior/SC400-1992/2888.html comes back with the carpet set being discontinued; anyone else know where to go, I'm in need also.

First Lexus, a 1992 SC400. Too much of a cream puff to pass up, 88K orig miles and all original. Hasn't been run since 2008 or started since 2010; fired up after WD40 in the cylinders and 2 gallons of "witches brew" ( hi-test gas, octane booster, top oil and injector cleaner) - one shot of ether and the sweetest idle I've ever heard! Other cars: 1986 MBZ 560SL, 2000 MBZ CLK320, and 2002 MBZ ML500. The SC is in the shop today having the AC converted to the new standards and all of it's bodily fluids replaced, tomorrow we go off in pursuit of new rims and tires (man are those factory rims ugly!) and then off to the beauty parlor for detailing. I'm going to be starting on the "niggles" next week: climate control LCD, minor interior repairs and dying, and does anyone know how to retrofit the '95 up cupholder (next to the radio) to the '92 model?