Curious about blow by on the 4th gen Maxima. Didn't want to crowd the help forum.


My '97 with 100k miles is the first high-ish mileage car I've ever seen that has ZERO blow by. Meaning I can lay a feather across the oil filler and it won't move.

Is the PCV system just really good on these cars or is my engine in perfect condition?

Is that typical for these engines?


I compared to a Kia, Toyota, and Volkswagon VR6 with similar mileage and they have between moderate and severe amounts of blow by.

 

to be honest, I wouldn't know a whole lot about the PCV system but I do know that it has a PCV and a blow by hose, which the Hose is on the front of the side of valve cover and the PCV is in the rear side of the valve cover. However with the oil cap, if you noticed, they can be tight when you try to take it off, so maybe they are pretty sealed well.

 

In my opinion I don't believe neutral blow-by pressure is necessarily indicative of a "perfect engine". I would say:
1. Your rings and valves are probably working as they were designed.
2. Your PCV system is drawing crankcase fumes and pressure as it should.
3. Owning cars since 1965 I don't see 100k miles as being particularly high mileage based on advances in engine design and manufacture since the 90's.
4. I have had a few cars that exhibited blow-by positive pressure until I replaced the worn out PCV valve.
5. Joking a little, you could have neutral valve cover pressure while all of your piston and crank bearings were grinding themselves into fine particles. :-) Not a perfect engine then.

Enjoy your well-engineered and manufactured engine. Keep using top tier gas or your catalytic converter will call out your piston rings and cylinders and win that fight.