Would a faulty PCV make oil turn dark quickly?

[Gebo]

I have noticed that the oil in my 98 LS400 gets dark really soon. I have always used Amsoil from beginning and am using the Japanese made Toyota Oil filter (special order). I took out the PCV and can blow air and suck air from same hole. Something tells me that I should be able to suck but not blow or blow but not suck and that one way was supposed to seal off. C'mon, don't go there

Could the fact I can blow back in the direction of my engine be causing the oil to turn dark really quickly? What else could cause the oil to turn dark so quickly? I have 3 other Lexi I take care of and all of them stay amber for 10,0000 miles or 1 year (my change interval). My LS400 is the only on that does this.

 

[iluvhonda]

what kind of air filter are you using? i hear free flowing air filters make your oil dark quicker. clean the pcv system with carb and choke cleaner.

 

[chubbs1]

No air shouldn't flow both ways. It basically 'sucks' gasses in at idle and as you press on the accelerator the ball should open and allow more gasses to flow through ONE WAY. I bet you that is why your oil is turning black faster...gasses and whatnot are returning to the engine oil. Get a new one!!

 

[Gebo]

I only use either Toyota or Napa air filter and change around 20K. I change my oil filter at 5K which is halfway between my 10K oil changes.

 

[wiswind]

I would install a new pcv valve using a Genunine TOYOTA part.
A correctly operating PCV valve is CRITICAL to preventing sludge and other breakdown of your oil.

 

[Gebo]

I just removed my wife's PCV and sucked and blowed. Chubbs1, you are right. When I blow back towards the engine, it seals right up. Shoot, it's been doing this for the last 3 oil changes.....

 

[Gebo]

Originally Posted By: wiswind
I would install a new pcv valve using a Genunine TOYOTA part.
A correctly operating PCV valve is CRITICAL to preventing sludge and other breakdown of your oil.


I agree with the Toyota OEM remark. It took me weeks to find the Japanese made Toyota oil filters. It has been ordered and will be here Tuesday.

 

[jorton]

Will occasional use of Techron + concentrate added to fuel keep the pcv system clean and operating properly?

 

[Gebo]

I use FP on a regular basis.

 

[J. A. Rizzo]

Originally Posted By: jorton
Will occasional use of Techron + concentrate added to fuel keep the pcv system clean and operating properly?


No, and since he uses FP regularly and that doesn't do it, that's 2 votes against fuel additives helping the PCV system.

The crankcase gases can be oil vapors and combustion blowby gases, neither of which will ever be clean, no matter what you add to the oil or fuel. The PCV system has to deal with cruddy stuff. That's just the way it is. Thankfully on many cars, changing a crusty PCV valve is a simple and inexpensive matter.

I like the idea of the PCV system "catch cans" that some have installed, because they can potentially keep some of that crud out of the intake. Whether it really helps anything in the long run is debatable, but I would think direct injected engines with their possible valve deposit issues could potentially benefit in a tangible way. Experimentation is needed here.

 

[shpankey]

Some suspect the EGR is even more of an issue than even the PCV on direct injection. So a catch can for the PCV and I know some people that get pliers and crimp off the EGR. This throws a code but they use some kind of aftermarket ECU to delete the code. They also run methanol injection to help clean the intake valves. Seems like the people that do all three have the best results. I'm waiting until I'm out of warranty before I take these measures... but hopefully I can stop and maybe reverse it a bit after that.