I have a 2010 GS350 with 200K. I 've put on 65-200K myself. I do very regular oil changes almost exclusively Mobile 1 with a filter every 5000 miles. I've noticed that I'm burning/using 1 quart every 1200 miles since 175K. I'm on a fresh new oil change now. I just cleaned the throttle body and will change the PVC Valve this weekend. Hoping that it helps.
At 150K I changed the spark plugs and the coils. I noticed oil coming into the spark plug cylinder on one or two driver side plugs/coil wells. No external oil leaks. I have yet to change the valve cover gaskets. But, could that be my oil consumption problem? Or if the PVC docent fix the problem, is the problem the piston rings? All thoughts and comments appreciated!

Jeff

 

How much oil was inside the spark plug holes? Was it enough to justify that 1qt every 1200 miles, because it has to be a pretty big leak. Have you raised the car removed the plastic lower engine splash gaurds and with a flash light examined the engine front and back? If not I would do this first just to rule out any external leaks.

As for 5k miles oil changes, lexus uses that as a sales gemmick to make it appear these cars are trouble free. But in reality, I would rather keep my oil changes from 3k-4k to avoid clogging oil galleries which toyota/lexus are known to have when you go over 5k miles. Having cleaner newer oil is always a positive, your engines internals will be cleaner. I replace mine every 3k miles

On my 08 with 200k miles, I had an oil leaks which turned out to be the seal on the front crank pulley. It was a cheap seal and took only 30 min to install. A common leak area could be the front timing chain cover, thats something to look for.

If no external leaks are found, then its possible your piston oil galleries are clogged. If this oil burning issue recently happened then it maybe possible to save it or slow the loss using engine cleaners like BG Moa and epr. If that doesnt work, then you can pour a chemical cleaner directly into the piston holes and let it soak in overnight. Then turn over the engine so that the fluids spray out, then install the plugs

 

Thanks for the reply. The Spark plug holes only had a couple of ounces so that doesn't account for the 1 quart. I've removed the splash gards and not noticed any oil leaks. It's amazingly clean for 200K. BUT, I will reinspect and the front crank pully area to make sure.

I'll switch to 3K changes. Great suggestion.

I've never attempted a top end cleaning with Seafoam or BG. But I may start with a Seafoam top end treatment first. As you suggest, on the next oil change at 3K, I'll do the full BG MOA and EPR treatment . I've read other threads that mention BG products.

Thanks for your reply!