Finally have the time to try and fix my oil consumption problem. I am thinking that the head will need to be rebuild, but would like another opinion.

Car has been consuming about 2 quarts or so every 3000 miles. There is visible wet oil on top of pistons 1-3, but piston 4 is clean. The car doesn't smoke, no CEL, doesn't burn any coolant, no visible leaks anywhere, no oil on spark plug threads, idles normally at 800rpm, and runs strong.

Motor is a d16y8 with 150k miles with 175PSI across the board.

Things I have done.
-Changed PCV
-New valve cover and spark plug hole gaskets
-Changed oil weight from 5-30 to 10-40
-175PSI across the board

Just need a second opinion on rebuilding the head. And please don't suggest to be to swap in a b-series as this is my daily driver and don't intend to do any swapping. Thanks.

 

Does it smoke? When? I'm going to suggest having someone ride in the back and watch as you accelerate hard, since it's probably valve stem seals if you have even compression on all cylinders.

 

Do a leakdown test.

 

I can almost guarantee you that the oil control rings are gunked up on the pistons and allowing some oil by.

With that said, 1 quart in 1500 miles is not worth pulling the head anddisassembling the bottom end. It's not bad at all. Seriously. You'll spend a lot of time and money replacing parts but you risk getting it all back together and still having an oil consumption problem (especially if you freshen the head without doing the rings, or vice versa), among other potential issues. It would be foolish to do so when oil costs $3-4/quart.

Just keep checking the oil every 500-1000 miles and topping off as needed. Burning a minor amount of oil is not a problem, but running the engine with a low oil level is a problem.

What brand of oil are you using?

 

Like I said it doesn't smoke, and if it does it's not enough to notice at all. I've had several buddies drive behind me and they all say the same thing, don't see anything.

 

Well it uses enough oil to destroy my cat. I am on my second cat right now. The thing I realized about the oil consumption is that it tends to use more if I am driving on the freeway. For example, if I check my oil and it is full and then I take a trip for about 200 miles of driving over the mountain pass etc when I reach my destination and check my oil it would either be halfway or low on the dipstick. But if I drive in town for short distances I can get more miles before having to top it off.

If it was oil control rings why would there be small fresh oil on top of 3 of the pistons? Would it just cause burning instead of small puddles on top of the pistons? It makes me think that it's somehow related to the head. As gravity and being in constant vac causes oil the seep through.

I've used Mobile, Castrol, Valvoline, Pennzoil, Chevron, and Shell. They all burn at the same rate even if I change it to a 40 weight.

 

1 quart/1500 miles isn't enough to kill a cat in the short term.

What cats are you using? Are they just throwing P0420s?

Odds are that you're buying cheap aftermarket converters with low precious metal content in the catalyst. These usually only last 0.5-1.5 years on OBD-2 cars even without oil consumption.

That's typical.

It may or may not be the valve stem seals. In my experience though, I would never freshen the head without also re-ringing and honing when chasing an oil consumption problem.

Conventional or synthetic?

 

oil can enter either by the piston rings or past the valves seals.

a product of bad rings will be lower compression and pressure in the crankcase causing oil to feed back through the PCV valve.

I'd say stem seals - the pooling on top of the pistons gives it away. I bet you'll see smoke on a cold start.

 

Nope this was a OEM cat. Not only did it throw a CEL, it was so clogged up that I was unable to get the car pass 70mph. The muffler shop also said it was contaminated.

This is conventional

 

I believe I only saw it happen once that it smoked during start up. But any other time it's always been a clean start up. Unless it just smokes so quick and little that whenever I run out to check it goes away.

 

with a d series, why not just replace? obd-2 zc vtec is under $500 on tiger. your engine sounds healthy for the most part, if you do swap it out ill buy it . some oil consumption is normal. do you blow smoke after sitting overnight/a few days?

 

Valve stem seals would be my guess too,good luck OP.

 

Sounds like you've got some other problems then.

Both my D16 and my D15 have burned more than 1qt/1000mi for tens of thousands of miles without issue.

If you really want to spend the money, you might as well start with replacing the valve stem seals. Don't be surprised if you're no futher ahead once it's done though.

 

Well my motor has been using oil since 95k. I didn't really think it was an issue, but now that I am planning on keeping this car longer that's why I was thinking about refreshing the head to see if it was the issue. It used oil for 4 to 5 years then the cat failed. But I'll go ahead and rebuild the head and see if it was the issue.

 

It's been my experience that pulling the head and having it planed and replacing valve seals tends to cause even worse oil consumption than what you started with. Like Targa said, i'd leave well enough alone unless you want to hone it and throw a set of rings and bearings in it.