Oil related misfire

[dx92beater]

I have been posting quite a bit in the oil forums regarding my 2006 Subaru Tribeca Ez30d H6 165k miles. Again This is a FLAT 6 and very difficult to work on without removing the engine which would not be cost effective right now.

History:

I purchased the vehicle "AS IS" from a dealership where it appeared to not smoke. They probably started it up and let it sit "x" amount of time since they had the heads up that I was coming. I started off with Rotella T6 5w-40 and an OEM Subaru filter. It smoked heavy blue smoke at startup for about 15 seconds and then stopped. It does not smoke during normal driving. Consumption was at about 1 quart every 800 miles. I'd also get a misfire code after starting it up P301, P303, P305. (Misfire for cylinders 1, 3, and 5 all on the passenger side cylinder bank).

After some advice here I did the following:

Kreen treatment for 1000 miles and then Marvel Mystery Oil/TCW-3 moving forward. Changed oil to Pennzoil Conventional High Mileage 10w-40. Replaced PCV valve with OEM one and verified that the hoses were clean. Consumption dropped to 1872 miles per quart!

Then I got greedy. Actually I wanted to protect the engine better during the cold PA/VA winters. I though that it would make sense to go with Castrol Edge HM 10w-40. To my surprise, it is acting just like it did with the Rotella T6. Same P301, P303, and P305.

I removed the oil cap and put a piece of paper on it to check for blowby and there is none.

Short of doing a very difficult to do compression test and leakdown test on this motor, I was wondering if you think this might be more valve seat/seal/stem related as opposed to rings.
I have already heard a 1000 times that a puff of blue smoke is valve stem seal related but many say rings due to the way the Subaru sits.

Can bad rings instantly cause a code on one cylinder bank like that?

Thoughts?

Thanks

 

[Ethan1]

This is relevant to my interests.

 

[RedOakRanch]

Maybe an actual misfire is causing the oil consumption due to the cylinder not being pressurized. Have you have the ignition checked out? Have the plugs ever been replaced?

 

[Eddie]

Subaru and other engines use O-Rings to seal the Spark plugs tubes to the cylinder head. If they leak badly, they can fill the tubes with oil which and cause arcing from spark plug to the tube. Only way to check is to remove a spark plug. I suspect that the engine is worn and, a combination of things is causing the consumption. Ed

 

[dx92beater]

Originally Posted By: RedOakRanch
Maybe an actual misfire is causing the oil consumption due to the cylinder not being pressurized. Have you have the ignition checked out? Have the plugs ever been replaced?


Wild idea. Well...the engine runs too well to have a long term misfire. The misfire is temporary and only transpires with synthetic oil so far.

The misfire only lasts for a few seconds at startup and not at every startup.

 

[dx92beater]

Originally Posted By: Eddie
Subaru and other engines use O-Rings to seal the Spark plugs tubes to the cylinder head. If they leak badly, they can fill the tubes with oil which and cause arcing from spark plug to the tube. Only way to check is to remove a spark plug. I suspect that the engine is worn and, a combination of things is causing the consumption. Ed


Could that in itself cause consumption and smoke at startup?

 

[dx92beater]

I also forgot to mention that it smells of burnt rubber from the exhaust from startup. That is not synonymous with the smell of rings IMO.....especially as a constant. The cap inside is burnt...even gasoline would not remove the deposits.

All misfire codes are on the passenger side of the engine as pictured e.g. 1,3,5 something is happening on that side.

 

[mk378]

You have a new to you used car that misfires, and you haven't even taken the plugs out?

Very good bet they have 165,000 miles on them.

And a compression test would tell you a lot. Much better than "it doesn't smell like rings" whatever the heck that means.

 

[dx92beater]

Originally Posted By: mk378
You have a new to you used car that misfires, and you haven't even taken the plugs out?

Very good bet they have 165,000 miles on them.

And a compression test would tell you a lot. Much better than "it doesn't smell like rings" whatever the heck that means.


Metal rings wouldn't smell like burnt rubber would they? The car only misfires at startup for a few seconds so the problem isn't spark plugs. Like changing spark plugs is going to fix a consumption issue?

Why don't you come by and take the 3 hours to change the plugs if it is that easy? A compression test takes a few hours on a flat 6 not 20 minutes like it does on an inline 4.

I'll watch you do that too.

Your response was completely useless.

 

[kc8adu]

difficult/time consuming to change plugs are likely to be neglected.
esp the one that is a real pain to change.
seen too many misfire issues caused by the one tough to reach plug that shops skip.
pull it and there is nothing left of it.likely original and never changed.
bite the bullet and change em.
may not be the issue but a good chance its part of it.
and a pcv issue on that side is likely.fixed plenty of mosquito foggers by replacing/cleaning out the pcv system.
Originally Posted By: dx92beater
Originally Posted By: mk378
You have a new to you used car that misfires, and you haven't even taken the plugs out?

Very good bet they have 165,000 miles on them.

And a compression test would tell you a lot. Much better than "it doesn't smell like rings" whatever the heck that means.


Metal rings wouldn't smell like burnt rubber would they? The car only misfires at startup for a few seconds so the problem isn't spark plugs. Like changing spark plugs is going to fix a consumption issue?

Why don't you come by and take the 3 hours to change the plugs if it is that easy? A compression test takes a few hours on a flat 6 not 20 minutes like it does on an inline 4.

I'll watch you do that too.

Your response was completely useless.

 

[Tosh]

You have a new to you used car that misfires, and you haven't even taken the plugs out?

 

[dx92beater]

Originally Posted By: Tosh
You have a new to you used car that misfires, and you haven't even taken the plugs out?


Turd troller.

 

[asand1]

Originally Posted By: dx92beater
Originally Posted By: Tosh
You have a new to you used car that misfires, and you haven't even taken the plugs out?


Turd troller.


If you have a misfire then a tuneup is in order. Why you would futz with oil for a misfire is beyond me.

 

[dx92beater]

Originally Posted By: asand1
Originally Posted By: dx92beater
Originally Posted By: Tosh
You have a new to you used car that misfires, and you haven't even taken the plugs out?


Turd troller.


If you have a misfire then a tuneup is in order. Why you would futz with oil for a misfire is beyond me.


Bunch of morons. Oil or coolant can't get onto a spark plug right? Like I said, get your internet gangster selves over here and change my easy peazy to change plugs for me. Definitely not coming to this section to get any advice. Spark plugs are going to fix bad rings or a head gasket. Yeah right! I can't believe that I bothered to post in this section at all, what a waste of time. Futz you trolling idiots too.