Synthetic X Conventional

mig25 · July 16, 2003

I am about to start using MOBIL 1 FULL SYNTHETIC MOTOR OIL in my LS400 1990 with 130.000 Miles. Could it pose any problems? Should I keep using conventional oil instead ? :huh:

Bubbles · July 17, 2003

No. I just switched to mobil 1 on my sc300 with 130000 miles. It's been 200 miles since and nothing wrong yet. The only problem with mobil 1 is that it costs a lot and the Lexus website says that they don't recommend switching back to conventional after synthetic has been used. Also if you use Mobil 1 make sure you used a good oil filter or else there's no point in using Mobil 1. My auto tech teacher also told me that if you want some performance gain, change all other fluids to synthetic if possible (manual transmissions can use synthetic oil, same with differential). By the way, I just went to Costco and they sell Mobil 1 a case of 6 for $24. That's $4 a quart. Not bad.

m2pc · July 18, 2003

I am going to switch as well. So what mileage intervals are you going to change oil at?

Bubbles · July 18, 2003

I'd do 4000 miles. People say do the 3000 mile change, but this is synthetic and it costs a lot. 4000 shouldn't clog up the oil filter would it now. And the Lexus sc300/sc400 repair manual says to do an oil change @ 7000 miles if driven nicely and @ 3750 if driven severely(i.e. stop/go traffic, heavy loads on engine).

I remember reading a website (could be a bogus one), that tells you to drain and refill oil and oil filter after 2000 miles from the first synthetic oil change. That means if you switched to synthetic at 120 000 miles, then at 122 000 miles you should do an oil change. I'm guessing this is because synthetic cleans all that gunk from conventional oil and gets dirty real quick.