Looking at several long trips in SC 300 coming up with 120,000 miles on the Lexus. It has been well maintained and never has had a mechanical failure of any kind.

How many of you have had car or engine failure while on the road that stranded you? If so what was the problem and how many miles were on your Lexus when failure occured? Just evaluating probabilities. Also, any mechanical or electrical failures that caused the car to not run in town? What was it and mileage on the car. What was the difficulty in diagnosing and repairing? For those without a mechanical failure, how many trouble free miles have you driven?

Thx...Lexcalibre

 

I've never had any mechanical failures on my SC300. I have a 1993 with 124,000 miles. The only issues I have had is my fuel pump ECU started dying at 93,000 miles and my main ECU went out at 116,000 and again at 124,000 miles. The ECU's have been the biggest hassle for me. I never had any issues with the engine or transmission.

I also need new control arms and a steering rack but those haven't completely failed me yet. They're in pretty bad shape for my car's mileage though.

 

Also for SC300's:

The mechanical fan clutch can go out anywhere between 200k-240k miles. This is noticeable as a "tornado" or "huge wind" noise from the engine bay. It is confirmed by attempting to push the fan into a free spin with the engine off. If the fan is not free spinning or otherwise stiff in any way, the fan clutch has gone bad and is locked in a 1:1 ratio.

It's a good idea to replace your crank pulley (aka harmonic damper/balancer) around 200k miles but I had one go to 240k miles still operating fine just before I had it replaced. Inspection showed that fine cracks in the rubber section were indeed forming so by 200k it is still a good idea to replace them before they go out and cause damage. Generally a very long lasting part though (25 or so years and 200k-ish miles).

1992-1997 engine ECU's generally need capacitor repair by now. As long as the failure is caught before any significant board damage they will be good to go again for years after the repair.

Fuel ECU's can fail at very high mileage or perhaps due to the age of these cars but the consistency of this failure varies from car to car. There is replacing with a factory fuel ECU or the +12V Mod w/relay to address this if it ever is an issue. If staying stock then a replacement fuel ECU makes more sense.

Steering rack bushings tend to be worn out with very old SC's. It's detectable as "shimmy" play in the steering especially on the highway-- even with a fresh alignment. We fix this with a new rack bushing kit (about $40 or so) from Daizen (unless other rack bushing kits are now available as alternatives).

The heater control valve can go out eventually-- specifically the plastic heater core bypass valve itself and not so much the VSV operated assembly it's a part of. There is a DIY fit it thread for this if the full factory assembly is too expensive (always shop around for OEM parts).

Lexcalibre, there are several little things that go wrong on these cars with very high mileage (assumed non-100%-highway miles) and it's similar to what you'd encounter with many vintage 90's cars. There are many DIY threads here to address several of the most common things that can go wrong with an SC300 or SC400.

Despite having several different ECU's for different functions throughout these cars it's generally a reliable high end Toyota. Maintenance is more than it is with a simpler Corolla but much more reliable than an older BMW.

The 2JZ-GE inline six in the SC300 and 1UZ-FE V-8 in the SC400 are both extremely reliable engines. Same with the automatic transmissions in both and same with the W58 5-speed manual in some SC300's (and swapped in R154 5-speed manuals for that matter). Same with the rear differentials also. It is rare to get stranded with either car. All of these parts of the drivetrain were very over engineered. The 2JZ-GE engines can, if maintained and cared for, go well beyond 200k miles. The highest mileage 2JZ I've heard of is one that made it to 500k+ miles and counting (albeit with consistent maintenance and likely some replaced top side components). 1UZ-FE's are the same engine from LS400's and some of those have done much more (there's a much publicized million-mile LS400 with the same engine and transmission as the SC400).

It depends on how the car and engine was cared for over its life to date, how it was maintained and if the occasional issue that came up was addressed. Component failures happen at very high mileage but with these cars it's rarely the engine's themselves. All of the 2JZ-GE and 1UZ-FE 90's Lexus vehicles have a very good track record for longevity.

Some issues are difficult to diagnose and some are not at all. The most trouble I ever had was when I needed to repair a check engine light related to my SC's EGR system so that I could pass a smog test and get my state registration renewed. I made a long thread detailing that diagnosis. Now I could probably nail that diagnosis and the needed repair down quite a lot faster. Mind you all the while the SC300 was driving very reliably and NEVER stranded me. It just had an EGR system malfunction I had to fix in order to renew my registration (in California). Sending my engine ECU in for capacitor repair and verifying its proper function also eliminated the possibility of phantom issues that an old and failing engine ECU can cause. That's why we always recommend it as a pre-emptive fix. In Florida you have no emissions testing anyway.

The only times I ever had an issue with getting stranded was due to one of the most common reasons for any car: a bad/tired battery that needed replacing.

There are many threads detailing different issues to look out for, Lexcalibre but generally these are very reliable Toyotas. They were built very well for their time and the quality of engineering still shows.

 

had my SC3 for a while before i sold it at 160k. It never got me stranded and the waterpump finally went out on it at 145k. The timing belt was changed before that so i was waiting for the waterpump to go to do everything properly. I would say if you havent yet, replace the waterpump/timing belt that youre supposed to replace at 100k and you or your mechanic look over brakes/fluids/suspension/tires etc before you leave for the trip. My alternator lasted until about 156k but that might be something to look at as well.

 

Thanks for the informative replys from everyone! Collective experience over time is the best indicator of potential future failures as these Lexus classics advance in years. I replaced timing belt, spark plugs, spark plug wiring, idler arm and pulley, water pump, cam shaft seals, valve cover seal, serpentine and all belts, brake cylinder & pads etc. at 120,000 miles. The spark plug wiring was aging and the water pump was showing the white residue sign of seepage. The timing belt itself was in excellent shape. Otherwise I have no other repairs! My SC is a garage queen and expecting to exceed 200,000 miles.

Thank you and any additional mileage/experience will be appreciated!