Excess Crankcase Blow by???
 

I recently had a post on a rear seal leak on my 2001 ES 300 with 96K MIles.which was fixed by my Lexus Dealer (See my Post Below)

https://www.clublexus.com/forums/es3...001-es300.html

What concerns me however is why it happened, So although it could have been a legitimate defective rear oil seal, I could not find any other posts from members with the same problem oman ES 300. Many such issues with the RX300 but none with the Es 300

So than I started thinking that maybe there is something else going on, such as excessive bow by, which could cause a seal to start leaking.

After I got the car back I did some basic observations to look for possible sign of excessive blow by but, with one possible exception could not find any.

I should preface by mentioning that as regular maintenance I changed my PCV valve 2 years ago, with an OEM PCV Valve

Drove the car at highway speed for about 40 MInutes, Came back home, and here is what I did (With the engine still running)

1) Removed my Oil dipstick and looked for smoke. Nothing.

2) Replaced my Oil Dipstick and removed the oil Cap, looking for Smoke. Nothing.

3) Replaced my Oil Cap and removed the Vacuum hose going to the PCV Valve, (Lots of suction)

4) Removed the PCV Valve. I Noticed some smoke coming out of the now empty PCV Valve hole in the rear Valve Cover. (Is this Normal?)

5) After close to 3k Miles, Oil still looks brand new

I should also mention that the car does not burn any oil, There are no visible signs of smoke out of the tailpipe, and so far no further of oil leaks.

There is some sweating around the rear Valve cover gasket, but no visible leaks so far. I know that this is common, and will deal with it as well as spark plugs change, this coming spring.

So based on my above observations, Was it just a defective Rear Main oil seal, or could I possibly have excess crankcase blow by. (Especially Considering Point No 4 Above)

Your comments would be appreciated.

Also, any other simple tests, or observations that I should do at home?

Thanks,

Phillip

RMS fail occasionally -- looking at one you wonder how they work at all !

With "blow by" you often get oil back in the intake -- you would see the oil.


Some cars have a greater incidence of failure -- many theories. With the thinner synthetic oils any space will leak - that is why the additives often work. Most of the high mile oils have a seal conditioned - they swell the seals

If the Oil was to get back into the intake than where would I see that oil? Would that be in exhaust smoke, or somewhere else?