Extreme oil burn, m35x

[SnowNYC1]

Hey guys, new to the forum here and not really car savvy so bear with me here

so i have a 2006 m35x with 120,800 miles on it ,I've owned it for a little over a year at this point and only put on maybe 3k miles on it to date and i love it a lot!

I tried to look through the forums for a bit about this, but i have a really bad oil burn issue........ 1qt every 30-45 miles...... thats not a joke even though i wish it was.
every time i start it clouds of blue smoke get shot out, drive it blue smoke, idle for a few minutes blue smoke.
my brother said that its a issue with the piston rings and that i might as well just crate in another motor. recently she developed a miss fire on the 6th cylinder and was basically undriveable.
so i went out to switch the spark plugs, when i pulled out the plug from the 6th bank it was completely drenched in oil. it was dripping oil from the end of the plug very badly.
popped in the new plugs and BOOM she lives!
so my questions are:
- is it the piston rings?
- is it the valve cover?
- should i switch my type of oil? (currently 5w-30)
- any steps i should take?
many thanks guys, hope ya can help me out!

[Ilya]

Welcome to the forum!

I'd start with replacing the valve cover and the o-rings for the spark plug tubes or what not (I'm not sure of the exact name) and go from there. It may be that simple and if you DIY it, not that expensive. If it's still an issue after that, personally, I'd probably get another motor. Also, do a compression test of the motor. It's possible the oil starvation, etc. has damaged other things...but maybe you've always caught it in time.

[EdBwoy]

That's truly excessive, your oil economy is worse than the fuel economy!

Could you clarify if the bottom of the spark plug (the threaded section) was the only part covered in oil or even the white ceramic part?
- If only the threaded part, it might need more troubleshooting
- If only the ceramic part, then it's also a spark plug tube seal issue, which normally requires the valve cover to be replaced.

Either way, since you see the oil in the tailpipe, there's something mechanical going on. If oil rose up high enough to soak a sparkplug, it's not good news. (Btw, did you remove any other plugs to compare?)

Actually, as a first resort, the other thing I'd suggest is to replace your PCV valves. They aren't exactly cheap, but if replacing them has zero effect on the blue smoke, I'd start scaling down what I'm willing to spend on this engine.

[Ilya]

There is a guide on how to replace the PCV valves in my signature (HowTo/FAQ link) that I wrote. They are like $9 a pop.

[SnowNYC1]

That's truly excessive, your oil economy is worse than the fuel economy!

Could you clarify if the bottom of the spark plug (the threaded section) was the only part covered in oil or even the white ceramic part?
- If only the threaded part, it might need more troubleshooting
- If only the ceramic part, then it's also a spark plug tube seal issue, which normally requires the valve cover to be replaced.

Either way, since you see the oil in the tailpipe, there's something mechanical going on. If oil rose up high enough to soak a sparkplug, it's not good news. (Btw, did you remove any other plugs to compare?)

Actually, as a first resort, the other thing I'd suggest is to replace your PCV valves. They aren't exactly cheap, but if replacing them has zero effect on the blue smoke, I'd start scaling down what I'm willing to spend on this engine.

Hey guys
sorry for the late response, yes i pulled all the plugs that same day and replaced them, i'm gonna link the pictures below.
The PCV valve was already replaced before, should i do it again?

https://imgur.com/a/YZDPI

Thanks for the help guys, i really appreciate it!

[Ilya]

I typically replace mine every 30k or so. So if you only have like 10-15k on them you should be fine.

Those plugs don't look so hot. I'd start with what I said earlier...valve cover + tube o-rings. But Ed is much better with motors than me so I'd also take his advice...

[EdBwoy]

No pro here, just a lot of experience knowing when to hold 'em and when to fold 'em.

The plugs don't look that bad to me, plus the top section doesn't look like it was soaked in oil (unless you already wiped them). To me, that means your plug tube seals are ok. Look on the sides of the engines and you should be able to see if your valve cover seals are leaking by as you'll see the oily mess.

With the info you have provided, since you already replaced the PCV valves recently, I would not spend any more money on replacement parts. I believe all your leaks are internal (which is why oil is getting to your tail pipe). As Ilya suggested above, a compression test would be money well spent to get a verified diagnosis. I'd do that and you can be better equipped to decide whether to fold.

[cruzad3r]

i was in your place and i opt for a used 70K miles engine from an 07. now you can try to do the following to "bandage" the situation

1- check to see if you're leaking, should be easy to spot and i'm not talking little leak here based off your first post
2- clean your exhaust pipe and check to see if it's wet or soot over several days -
3- buy this and use it when you change your oil https://shop.advanceautoparts.com/p/bar ... 11205886-P
note - look for a coupon code and order online to save a few bucks. you will need to run several bottles
4- carry extra quart or two of oil in the trunk and add as necessary

if you want to learn more about the cause, there is an episode on Wheeler Dealer that Ed walked you through an oil consumption car. To be honest, you have to see if it's worth the cost of swapping an engine or trade in for a newer car. my swap cost me around 3600. that's a used engine, labor and misc parts, including CAT converters and O2 sensors.