gzaid1

I am new to the forum and I just purchased a 1997 Lexus LS400 with 147k miles. The car is in excellent shape and runs like a champ. I've already put 2500 miles on the car with no problems and I'm also getting excellent gas mileage.

I have traditionally used Castrol GTX 10-30 (conventional) oil in all of my cars - both domestic and imports. My questions is as follows: would you guys recommend me switching to Mobil 1 (full synthetic) motor oil & going 5000 miles between oil changes or sticking with the conventional Castrol 10w-30 and changing it every 3000 miles?

When a vehicle has this many miles, and assuming it's always had conventional oil, is it harmful to change it to full synthetic? Are there any possible ramifications or repercussions in doing so?

I am very pleased with this LS400 as it's my first Lexus to ever own and drive. It's truly a pleasure to drive and travel in. I will soon be in the market for one of the newer '07 LS460 models.

Any help will be greatly appreciated.

Thanks in advance for all of your help.

PS - I live in the Houston, TX area where our summers are brutal with lots of heat and high temperatures.

Thanks again.

PureDrifter

iTrader: (10)

the 3000mi oil change is a myth.

i run ~8k mi between changes, bosch filters and Mobil1 full syn. 5w-30 (switching to 10w-30 due to the weather in my region).

gzaid1

I guess my question is more regarding whether starting to use Mobil 1 synthetic oil in my '97 LS400 is a good idea if the car has never been used to synthetic oil and it's already got 147k on the clock?

PureDrifter

iTrader: (10)

yeah you'll be fine, my current LS was switched at ~100k mi and my old LS at around 125-130k mi without leaks. just make sure to use the correct weight oil.

steveski

I am running 15l on Mobil Extended but also use Mobil1 filter. I can't see that swapping at high mileage to Mobil1 SYN would be bad as Pure said. If anything you'll notice cleaner emissions, etc. When I got my LS inspected last month it had 235,000 miles. The computer report was crazy - tech said the engine was perfectly clean (Mobil1)

jgc

I started using synthetic when I got my car at 100k, Im not sure what was used prior to it but I've always used synthetic on my cars.

smokincigs

I agree. Both of my LS400s got switched at over 100k with no problems whatsoever.