Fern

Just purchased a '99 lexus rx300 and noticed that inside the valve filler cap it appears to have rust/varnish on a metal part that diverts oil into the crankcase?

Any idea what this is.

The service manual shows oil intervals being done every 3700 miles, therefore this can't be sludge is it?

Car currently has 48000 miles.

Hope I haven't purchased a sludge pit!

Need input desperately before I go postal on dealership.

Fern

ederny

Well Fern, your 99 is like mine and probably most others. These engines just build up a coating inside. Not a big problem really. Most engines will build up a film on cooler sheet metal housing parts. The question is: can you scrape off a film on that plate just below the filler cap, with say, the blade of a screw driver? If there is a lot of build up (more than an 1/8 of an inch) you might want to use a crank case cleaner (the 5 minute kind) or take it to a Toyota dealer and have them do a power crankcase flush ($125 to $150).

Of course, change you oil at recommended intervals and be assured Lexus extended the power train warrenty on these engines to help us all out.

Good Luck.

Fern

Good to hear this is a common problem.

I tried to remove some of the varnish/film with my fingernail and it came off. It was very dry, much like paint that blistered and was loose.

I used the term "varnish" since that's what it apears to be.

Also that part inside the crankcase that appears to divert oil seams to be rusted. So you say this is common. I just traded in a 1993 Nissan Pathfinder for the Lexus and don't ever recall seeing this on my vehicle and I did 90% of the oil changes myself.

So, you say its ok to use an engine flush "the 5 minute type"? Thats what I'm trying.

I am reluctant to use a power flush at Lexus as my research had found mixed reviews...

Thanks for the help.

Cheers,
Fern

ederny

By the way, an engine flush will not clean this part at all, but will do the proper job where it should on the engine parts. Especially important is the metal screen on the oil pump pickup in the oil pan. Clogged screen causes oil starvation at high rpm and/or cold engine (oil).


Right, sort of a rust coating is common on this part because it is cooler than the block pistons and oil in the oil pan. What actually causes a mix of rust and sludge on it is the hot bypass gasses leaking past the cylander walls (normal) from the combustion chamber. These gases contain a lot of water (H2O) as a normal byproduct of combustion - you recall seeing steam coming from the exhaust of all cars on a cold day at start up (rich mixture so lots of mostiure). On many short trips the water will condense on the cooler parts and sit there (and rust a bit). Right, it happens more in engines that are driven on short trips, moreso in winter. Longer engine runs seem to heat the entire engine more completely.

Now, on the other hand, your "crankcaase ventalation system" should be working properly. This is just a vacume line sucking these blowby gasses out of the crankcase.