Burning Oil/Oil Loss

[4RunnerMexico]

2003 V6 with 209k. I usually have to add a quart around 3,000 miles into an oil change. I have no idea where its going. There are no oil leaks, replaced valve covers, crank seal. The PCV valve is good.
There is never any smoke, and the coolant is clean.
I am sort of beginning to think this might be early signs of head gasket failure.

I ordered a Blackstone Labs test kit, Ill send in in when I'm due for an oil change.
Does anybody with a high mileage V6 have to add oil? Im just trying to figure out whats considered "normal".

 

[Morphyne]

I have an 07 V6 4wd sr5 with 215k miles and I lose a quart every 5000 miles. I use mobil 1. Currently trying other oils. Edit: same thing as you. No leaks, no smoke, good PVC, clean coolant, etc...

 

[4RunnerMexico]

I have an 07 V6 4wd sr5 with 215k miles and I lose a quart every 5000 miles. I use mobil 1. Currently trying other oils. Edit: same thing as you. No leaks, no smoke, good PVC, clean coolant, etc...

It loses more oil when I run anything besides Castrol GTX High Mileage, so Ive been sticking to that

 

[Seymore Butts]

My '08 v6 manual says that maximum oil consumption is 1.1 quarts per 600 miles, which sounds so bad that I wouldn't be able to sleep at night.

You guys are probably losing some through piston rings, so a lab test would give you an idea of how much the remaining oil is diluted with fuel and condensed atmospheric water that comes down past the rings. It would probably mean switching to a more frequent oil change interval.

 

[waypoint]

I'd start by replacing the PCV valve with a new Toyota part, if the new PCV was an aftermarket part. And examine the rubber PCV hose for cracks or holes.

Next step would be removing and examining the spark plugs for indications of oil burning...if they're all black, you have a system-wide problem. If just 1 or a few are black, it's localized. Label the plugs with the cylinder number each came from so you can reference them.

While the plugs are out, a compression test is done. Map the compression numbers back to the spark plugs, and look for a pattern of low compression and black plugs.

 

[Morphyne]

I've done this and the spark plugs are fine as is the PCV

 

[waypoint]

I've done this and the spark plugs are fine as is the PCV

Possibly the PCV passage inside the valve cover is blocked with sludge?