Hi guys i recently got my brother rx 300 it got over 200k miles but its in great shape. Run smooth and lots of power. No leaking fluid and not consuming oil. It a well maintain vehicle. He always take it to the Lexus service center for maintenance and service.

Oil change is coming soon around october and found out theyre using conventional oil for this car. My question is should i keep using the conventional oil or change it synthetic or even synthetic blend?

 

I am using Mobile 1 HIgh Milage Synthetic. I also add STP oil treatment/stop leak. I used Mobile 1 synthetic for years,
but when my valve gaskets started leaking, I switch to high milage. Synthetic oil might cause seals to leak.
But will help engine run cleaner.

 

I'd stay with whatever the Lexus service department has been using. If it is conventional oil, keep up on the oil changes religiously—especially if you drive it short distances, operate the vehicle in a lot of stop & go traffic, etc.

 

Was your brother changing the oil at the recommend interval which I believe is 7500 miles? IMHO that's a long interval for conventional oil. My choice would be semi synthetic and change it between 3 and four thousand miles with a OEM oil filter Full synthetic may cause oil leaks at seals and gaskets. BTW what year?

 

I go 10K intervals on mine with an oversized HP K&N 2009 oil filter. Usually will experiment with a new oil each time. Running Motul 5W30 right now.

 

I have seen Motul is speed shops. Did not venture to ask price.

Salim

 

$33.29 for a 5 liter jug

 

I would stick with conventional. When I first got my RX with ~150k miles, I switched to synthetic as it seemed like a no brainer to me. However, doing this caused a crack in the crank case to form and a minor oil leak to start. Took it to the mechanic and they said it would be 1200$ to fix. Basically: stick with the oil you have been using.

 

You may be the first person in history to make this diagnosis.