dgdarien

I barely passed a smog check not too long ago, and the tech said that I should replace the hose connecting the PCV valve to the intake manifold because it was really stiff.
This hose is coming up on 15 years old but I understand that this tubing needs to be stiff to withstand some of the vacuum pressures.

Can this actually affect any smog related performance, or was the guy making things up as he goes?


#4 in diagram. Part# 17131-P2J-000

tony_2018

oem hoses aren't stiff, they are firm but not stiff. Its probably past the point where it could probably fall apart.

dgdarien

Well it is pretty stiff, but not breaking or cracking. I managed to flex it a bit and it didn't show any signs of distress. Could it still somehow affect emissions testing? I am considering checking/replacing the PCV itself.

tony_2018

hmmm....there really isnt anything monitoring bllowby

Jimi Hondrix

That hose needs to be fairly stiff so it doesn't pinch off, especially at the elbow where the PCV valve attaches.

MisereNoire

I did my PCV hose recently, and what I found was this:
The hose was stiff, but not yet cracking.
The grommet-style end that presses through the IM was rock hard, and did not allow a PCV valve to seat snugly anymore. The other end of the hose was oil impregnated and was allowing air/oil leakage past the breather chamber box nipple.

So basically, when the hose has reached the point where it starts to swell from oil permeation, and the oil and heat exposure causes the hose to harden, then the hose is no longer performing to satisfaction and should be replaced. (At this point it is extremely prone to cracking at the ends, and can dirty up your engine with leakage).

As for affecting smog performance...not likely unless it breaks entirely (which should make it run cleaner...not dirtier..but only marginally so. They just frown on blowby gases being vented to atmosphere), and even then the inspector is just being a nitpicky representative of the state, which has it's collective head up it's ***.