I have an '02 RX300, 164k miles. We've owned it since new and have always used synthetic oil. Oil change intervals have been in the 4-5k mile range.

I've read that oil sludging doesn't occur with synthetic oils. Is this correct? I ask because recently the oil consumption has increased alarmingly; now about a quart every 1,000 miles. No visible leaks, no oil in coolant, no smoke on startup. Could this be sludge-related? I recently replaced the PCV valve but that didn't seem to make much difference. I haven't pulled the valve cover to check yet, I guess that is the next step.

We replaced the trans about 18 months ago, but I don't see how that could affect oil consumption. A number of the oil changes over the years have been at the quick lube type places and I guess it is possible they used dino oil while telling me they used synthetic (I usually stand in the bay and watch them, though).

Any ideas?

 

I would pull a valve cover to be sure. Then you could make the switch to Mobil-1 5W-30 High Millage motor oil. Very good add package to clean up the motor, and protect it.

 

X2, pull the valve cover.

If the quick lube shops did actually use synthetic as you requested, then there should not be any sludge.

What oil are you currently using? Many people on here have had consumption issues with Mobil 1, obviously not as severe as the consumption your engine is having, but some consumption nonetheless. I've had consumption with Mobil 1 EP, and the regular Mobil 1 in 5W-30, and 0W-30.

However, I have absolutely zero consumption when using Pennzoil Platinum, I usually do a 4-5k OCI.

 

Mobil 1 High Milage 5W-30 is in it right now, so maybe that is part of the problem.

I was considering an AutoRX treatment, but if sludging is not a problem, would that be worth it? I'll pull the valve cover and see what it looks like first.

 

Note Castrol oil 0-30 European synthetic really does a good job of cleaning engine....That is if you dont have sludge. Good luck

 

Actually am using Royal Purple 5W30 for a change, will let you all know how it goes.

 

Pennzoil Ultra is also excellent at cleaning the engine. $26.50 at Walmart. Must say that my 2001 Rx300 with 145K miles treats the oil very well. Have 3500 miles on this change and the level has not dropped and the oil color is still light honey. Very happy.

 

synthetic oil is white with transparent, which is easy to check when you just replace the oil.

By the way, at my place, i always go to a garage to change oil. they charge $40 for the synthetic oil & labor. I think it is a reasonable price, comparing with at other places. but every time when i check the new oil , i found yellow color blended.

 

"synthetic oil is white with transplant"

What?

 

sorry, i mean transparent

 

I change the Mobil 1 5W-30 every 10K miles...that's not a typo, ten thousand miles...in my wife's '02.

Still consumes -0- oil over the change interval, and it looks cleaner at 10K, which is right now, then the same oil in my 8 quart sump STS's Northstar motor, with only about 7K on it.

I need to change it this weekend, but I'll letcha know if it ever develops any sludge problems. It's still a low-mileage vehicle.

 

A member on BITOG, used to have a 99' RX, and he ran 10-12k OCI on Mobil 1 10W-30, with no consumption. So it is definitely possible to run Mobil 1 with long intervals, and no consumption, but all engines are different, and some prefer Mobil 1 while other's don't.

 

Warning: Negative statement ahead: I never trust those quick lube places. If you really care about your car, do the oil changes yourself, they're simple to do. That way you'll know what is really going into the engine.

Then again, I hardly believe 4-5k OCI's would not cause sludge accumulation even if you were using todays standard dino 5w-30.

My .02.

 

May be negative, but is still true. I feel for the honest Quick lube owners (though I do think they are very few) but way too many of them (quick lube, not the honest owners) have been shut down or forced to sell because of blatently dishonest practices. Have changed my own oil my entire life and will probably stop driving when I can't do it any more. Simply don't trust anyone to pull my pan plug. (comes from observation from working in automotive most of my life)