When PCV valve is replaced, does/can oil consumption gradually get better, or immediately?

[paulri]

I have read a few people here say oil consumption was aided when the PCV valve was replaced. The one for my highlander is getting replaced this week.

When people have changed the PCV valve and noticed a drop in oil consumption, was the effect almost immediate, or did it only get better gradually?

 

[jetman]

immediate, if the old one wasn't doing its job.

 

[paulo57509]

Reduction in oil consumption should be immediate, provided there's no other mechanical issues.

Replace the PVC per the maintenance schedule or blow test them (with low pressure shop air). Shaking them is not a valid test, as I found out.

LS400 - Intake manifold w/plenum removed - engine oil. ~90k miles.

The intake ports were pretty oily too. Apologies for the poor image.

Oily intake ports; clean valves.

I wish there was an easy way to check to see of the Techron cleaned the ports. No way to snake a fiber optic camera in there....

 

[paulri]

Thanks. I'll see if I notice any difference.

 

[Revving2Redline]

I clean the pcv valve out with the CRC Mass Air Flow sensor cleaner. Changing oil regularly and using a couple of ounces of Gumout Multitune right before oil change in crankcase.

 

[Shel_B]

Reduction in oil consumption should be immediate, provided there's no other mechanical issues.

Replace the PVC per the maintenance schedule or blow test them (with low pressure shop air). Shaking them is not a valid test, as I found out.

The intake ports were pretty oily too. Apologies for the poor image.

View attachment 120830
Oily intake ports; clean valves.

I wish there was an easy way to check to see of the Techron cleaned the ports. No way to snake a fiber optic camera in there....

I played around with the image a bit and got a little improvement.

 

[Trav]

I have read a few people here say oil consumption was aided when the PCV valve was replaced. The one for my highlander is getting replaced this week.

When people have changed the PCV valve and noticed a drop in oil consumption, was the effect almost immediate, or did it only get better gradually?

A lot depends on the location of the PCV valve, if it is above a baffle in the valve cover there may be no difference at all if the baffle is clogged.
This is an example. If the holes on the inside of the cover (in the plate in the middle) are clogged there is no PCV flow.

 

[paulri]

In all three cars in my sig, the PCV valve has been changed. I've only driven them 1000 miles or so apiece, so its a bit too early for me to tell if oil consumption has dropped, although it is clear it hasn't been eliminated. I'm still getting some in all three cars.

Not sure if this relates or not, but from what I've been told, the baffle for Toyota cars (in my Highlander & Sienna, not sure about the Camry) is actually right under the oil fill cap. So if I'm understanding things correctly, the PCV valve wouldn't be right above the baffle.

 

[bubbanik]

Immediate. My wife's 2020 Kia Soul that she bought used with 4K miles on it was losing/using a quart every couple thousand miles. Only 12K miles on the odometer so that was a concern. Changed the PCV valve, which still had some rattle in it, and all the oil consumption stopped. I think the valve was $13ish.

 

[paulri]

Glad you replied, bubbanik, so I could update this thread. In the first oil change after the PCV valve was changed on my Sienna, oil consumption went from 1/3-1/2 quart in first 3000 miles, to nothing in first 3000 miles. After that, there was some oil loss, but still less than before. Anyways, it had an immediate effect.

Unfortunately, for the other two cars that I have that had the PCV valve changed, doing that did nothing for oil consumption. Gonna pour in some HPL EC to see if that can lessen it.

 

[SureshR]

In an earlier car, I had an oil separator rather than a PCV valve, that had got clogged due to a mechanic overfilling engine oil (before I got the vehicle). Oil consumption was quite apparent, and there was blowby from the dipstick hole .. but no smoking exhaust, no loss of power from the engine or anything else. That was one reason I could get the car for a song. Take the oil separator (under the intercooler) out, clean it with diesel + then a few sprays of WD40 and reinstall it, and the oil consumption just stopped.