During purchasing a CPO 2009 IS350 with 69K yesterday, I was informed by the dealership that they had always used Pennzoil 5W-30 for my car's oil changes. I told them I was gonna go with synthetic. They told me their mechanical "guru" said that with the 350 engine my OCI should stay at 5K no matter if I used conventional oil or synthetic. I thought it an interesting. He said I could stay at 10K on my LS. What do you think? Is that engine so tough on oil?

Also, I got the shock of my life when pulled it in the garage and heard the "ticking." My heart sank until I found many of your responses saying the ticking was from the DI and was perfectly normal. I hope this may help some on you.

 

There is no shortage of opinions about the proper OCI on our searchable archives. Feel free to delve in.

I think the most useful are those that include actual oil analysis results, as science trumps speculation any day. The Blackstone UOA thread is particularly interesting:
https://www.clublexus.com/forums/is-...oa-thread.html

 

Understood. But Im trying to be very specific to this one engine. The one in the 2009 IS 350. Is that engine so rough on oil that a synthetic will only last 5K? The dealership told me my LS's were so easy on oil that 10K was no problem with them. Just trying to figure out why this engine is so rough on oil.

 

And thanks for that link. Very informative.

 

The engine in the IS350 isn't particularly rough on oil. Look at the Blackstone thread I gave you; plenty of people running 10,000 mile OCI.

If you want to know what is right for your particular engine, do a Blackstone UOA when you change your oil. The report you get back will tell you whether it is safe to go longer next time.

 

Ever since my purchase of my IS350 back in April '11, I've DIY'd all of my oil changes. Each time I use the same full syn Mobil 1 and I add another 500 miles to the interval. Trying to see at what point I can find a measureable loss in fuel mileage. At 8k now, and still no change. Next will be 8500.

 

That was my understanding but after the Lexus mechanic said what he said I started to wonder....