2012 Odyssey odd bypass valve deposits PICS

[Brybo86]

I took off my upper intake manifold today for kicks and giggles

There were a small amount of deposits in the wells of the lower intake manifold near the left side/by pcv inlet.
I cleaned them out with a small screwdriver.
Shown on the towel.

I found some black deposits coated around the bypass valve on both butterfly valves
It almost looks like it was painted/caulked in.
They were brittle black , chipped off relatively easy.
I cleaned the throttle body using the brick on pedal method. It was hardly dirty. But the minimal deposits in the TB butterfly were a thin smooth consistency like the stuff in the intake manifold. But not quite as brittle. They were a little more goopy.

I did manage to crack off the little tab on the back of the airbox that holds the wires for the MAF sensor.
Gotta be pretty common to snap it, I don't see how the wire can be removed without breaking the tab. O well.

Anyone else seen deposits like these?

 

[SubieRubyRoo]

Yes, that's not really odd. It's par for the Odyssey course with VCM engines. The overarching idea is that the deactivated cylinders develop issues with the ring packs, and let oil mist by causing consumption. The PCV will recirculate the oil-mist-laden crankcase vapors into the intake, and they eventually accumulate in the intake and on the flappers like you found. Mine was the same way when I disassembled it shortly after I bought the van with 134k. I'd say it's a safe bet that your Ody: doesn't have a VCM disabler; and, spends most of its time putting around with the Eco dash light on. Chip it off, move on, and start using the full range of throttle travel more frequently!

 

[Brybo86]

Originally Posted by SubieRubyRoo
Yes, that's not really odd. It's par for the Odyssey course with VCM engines. The overarching idea is that the deactivated cylinders develop issues with the ring packs, and let oil mist by causing consumption. The PCV will recirculate the oil-mist-laden crankcase vapors into the intake, and they eventually accumulate in the intake and on the flappers like you found. Mine was the same way when I disassembled it shortly after I bought the van with 134k. I'd say it's a safe bet that your Ody: doesn't have a VCM disabler; and, spends most of its time putting around with the Eco dash light on. Chip it off, move on, and start using the full range of throttle travel more frequently!

Thanks for the reply regarding deposits.
I got the van about 3k miles ago and installed the S-VCM muzzler at that time.

 

[PowerSurge]

Good deal. These engines I wouldn't recommend doing extended oci's.

 

[SubieRubyRoo]

OP, good plan. I believe the underlying J35 is a good engine, gone bad thru mileage aspirations. Remove the VCM interference (as you've done) and as long as there was no damage already done, will be a good, dependable mill. I did UOAs on mine out to about 7,600 miles which is probably a safe maximum to avoid UOA costs.

 

[bulwnkl]

The J35Z5 in my Ridgeline is a great engine. Very durable, very reliable. I've taken it out to 10k on oil changes, per UOA. No problem in my climate and service conditions. YMMV.