murphysf

I have a 2000 Lexus RX300 with about 269k miles. The car has the toyota 1MZFE engine that is known for sludge.

With the age and mileage is there any concern to switch to a synthetic oil.

I am a do it yourselfer and don't mind the extra cost.

I plan to keep the car as long as I can, no plans to ever sell it, will keep it until it needs a major $$$$ repair or or gets in a bad accident.

I heard there are some negative potential concerns about switching to synthetic on an older vehicle with high miles.

I am going to change my oil today so am looking for feedback so that I can make a decision.

Thanks!!

Bill Dowd

The highest mileage I switched to synthetic oil was 168,000 miles on a friends car and no problems, if you don't have any leaks issues. I would use 10-40 to start and keep an eye on the oil level for the first few thousand miles. I bought a 2001 RX300 2 years ago with
130,000 miles and switched to mobile one 5-30 no problems and Max Life for the trans and power steering. the trans just let go at 158,000 miles. I had it rebuilt by Leons transmission in Costa Mesa CA they also upgraded the planetary gears with new types this has
been the weak point in the trans and it works great now. I also plan to change the trans fluid about every 25,000 miles to keep the beast running free of problems.

ukrkoz

Like Bill above said. As far as engine is not taking oil in any form - leaks of blow by burn out.
I suggest to do trial - go for synthetic blend first and see how oil level stays. If it does OK, go for full synthetic. At that mileage, heavier weight oil, of course. Unless you live in Alaska or them real cold states.
Otherwise, it is not feasible to keep adding expensive oil on oil taker.
Btw, I do O'reiley synthetic for couple years now. Does just fine. Oil is oil, likely made same plant as fancy ones anyway. If you really don't care about expense, no oil better than Amsoil. I did 15 000 miles oil changes with it on our then 99RX300 and could go longer. I think, I did 17 000 miles once, with filter change in the middle. I always do best filter I can find, that's where I do NOT save.

Baetke

If you do regular oil changes and don't do a lot of short trips, sludge is a non-issue.
What problem are you trying to solve by deviating from the manufacturers recommended oil?

YotaMD

I've owned a slew of high mileage vehicles and am a firm believer in full synthetic oil in all cases. If you switch and discover some leaks then I would simply fix the leaks. If a leak pops up in a very inconvenient place then maybe I'd consider using a high-mileage blend to try to band-aid the problem.

You can buy full synthetic Castrol Edge or Penn Platinum on sale at most parts stores any given week. The sale price is typically $25-30 for 5 quarts. At that price I think it's silly not to use full synthetic and practice extended change intervals.

I do 10k/12month changes on my 99 Land Cruiser with 260k miles and did the same on my Supra (turbocharged and abused) with high mileage. No problems over a combined ~13 years and 150k miles.

Make the switch and never look back!

xiang

I usually buy my vehicles at 100k miles and I've always switched them to synthetics immediately. Never had any issues. My 00 RX300 I got at 220k miles and switched, no issues so far, now at 250k.