Additive for high oil consumption with bad rings

[Jerub_Baal]

Quest,

My son bought the car last summer (a year ago) when the engine had 87k miles on it. We did an oil and filter change using Mobil 1 10w30. (We changed the oil and filter again this summer before he went to school.) I changed the air filter at the time he got the truck with an OEM filter. I don't remember the condition or type of air filter that was in there. It was either this Xterra or my other son's car that had a K&N in it. I will try to figure out if the K&N was in the Xterra. If it was, I wonder if the lower efficiency of that air filter could explain the cylinder wear.

We need to get his car in as drivable a condition as possible for him to get through the school year before any serious mechanical work can be done.

 

[Vikas]

Costco has $150 boroscope with 9mm head and detachable screen. If he is your good friend, here is your chance to justify a great toy for yourself

- Vikas

 

[Jerub_Baal]

My son's car is 750 miles away from me. This is a long distance diagnosis via phone and email. I won't get to check the car out myself until next spring, if it get be nursed along until then.

 

[mechtech2]

So it suddenly started using oil at this high rate?
Did he overheat the engine or run it low on oil?

 

[Jerub_Baal]

Neither. We cannot explain it.

 

[addyguy]

Try Restore - I've heard it's one of the few products that works in this situation.

 

[Jerub_Baal]

I'm considering Restore a last resort. I'm starting with thicker oil (Rotella 15W40), cleaning (Kreen), and a PCV valve replacement. If this combination keeps the oil consumption reasonable and the oil quality acceptable with 3k OCIs, I'll call it a success.

 

[ltslimjim]

Why not use Kreen as a piston soak and then in the oil, change the PCV vavle and use Red Line SI-1 in the fuel system to help there as well? (only b/c Red Line claims it will clean the PCV valve?)

 

[Jerub_Baal]

The only reason I'm not recommending the piston soak approach to my son is spark plug access. I've changed the plugs in his car and two of them are tough to get to and one (either #5 or #6, I can't remember) is a completely blind access against the firewall. If I had his truck at home with me, I would do the soak approach.

I have heard the Kreen application does some level of cleaning to the PCV circuit due to its volatility.

 

[cronk]

If the PCV valve is dirty, no oil or fuel additive is going to help. Go to a Nissan dealer and pick one up, should cost you around $15. Should be pretty easy to get to on an Xterra.
I used to work at a Nissan dealer, the 3.3 engine in those trucks is not known for oil consumption, in fact, my wife's 2000 Quest van has the same engine and with 130k miles, there is no noticeable consumption in a 5000 mile oil change.

 

[Quest]

given the estimated oil consumption rate, nothing can do RE: "piston soak" or PCV valve replacement would have dramatically reduce oil consumption rate.

nurse this engine with thicker oil until you or someone has the time to go through this engine.

focus on valve stem seals, worn valve guides, carboned up oil control rings and glazed/scoured cylinder walls.

Q.

 

[Jerub_Baal]

My son got this Xterra, with the 3.3 liter V6, because he wanted a very reliable car/truck while in school. It had 87k when he got it. It has been running fine for him for a year until "suddenly", driving back to school this fall, the oil level was below the dipstick. He's been adding oil but not driving it much at all ever since.

We changed his oil and filter right before he left for his 750 mile drive to school. He has been consuming oil, and the oil is turning black very quickly. Now the dealer tells him the cylinder walls are scored. I really don't get it.


I'll tell him to get the PCV valve from the dealer. I suspect Quest is right, there's nothing that will help short of a tear-down and rebuild, but we have to try.

 

[Trav]

IIRC Nissan had some issues with the catalytic converter coming apart and ceramic particles being sucked back into the combustion chambers causing the exact symptoms you describe.
Immediate very high oil consumption with scored cylinder walls.
I have no idea what years and models this happened to its just something i remembered with Nissans from the era.

Maybe look into this a little deeper because if the cat is flaking it will do the same thing to the new short block or used engine.
If the walls are scored its a done deal, nothing will help.

 

[Vikas]

I have heard that too. The pre-cats dis-integrate and then gets sucked back in the exhaust ??? How in the world it gets back there? Via EGR?

He says he has has VQ 3.0 engine. I have heard this problem on 3.5 and the 4-cyl but NOT on the venerable 3.0

 

[Jerub_Baal]

I mistakenly called it a 3.0 liter in my original post. It is actually the 3.3L VG33E V6.

This lead about the cats disintegrating is very interesting. I'll look into it.

 

[Trav]

Quote:
How in the world it gets back there? Via EGR?


IIRC that was the case.
Like i said i don't know the models or effected engines but if one or two were having issues in that era there maybe more but may not be as well reported.

Scored walls are most likely from broken rings, a few causes are over revving, detonation, dry start after long term storage with no lube in the cylinders and over heating to the point of piston bind. Scoring can also be caused something being ingested.
I have seen rebuilt engines where the ring gap was not correct doing it also.
Material failure of etched blocks like Nikasil and old Vega blocks also got torn up with normal use but i don't think this is applicable to the Nissan

 

[Vikas]

Is Nissan the only company using the pre-cats? Most other makers don't have pre-cats (at least they don't commit suicide that I know of!). Everybody uses EGR, but I have not heard of any other engine sucking the cats inard and committing harakiri.

 

[Jerub_Baal]

The majority of what I have been able to find about the Nissan cat isuue is this:

It is primarily concerning 2002 Altimas and Sentras with 2.5 liter engines. As stated, the pre catalytic converters have experienced a breakdown and the resulting particles get drawn into the engine and score the cylinder walls and causing sudden high oil consumption. If nothing is done, it gets progressively worse.

I don't know if this phenomena is what my son is experiencing but the stories I have read line up with his exactly. At this point I don't even know if his 3.3 liter Xterra has a pre cat. If it does, it seems it at least needs to be checked.

 

[Trav]

They list a front and rear cat for left and right side so it looks like it uses one.

Quote:
don't know if this phenomena is what my son is experiencing but the stories I have read line up with his exactly.

Yes that was the first thing that came to mind when i read your post also.
Keep us posted on this would you, it may be helpful for future reference.

 

[Jerub_Baal]

Well Trav, if it wasn't for your post, I would not have thought of this failure mechanism. The incidents of Altima problems is extensive but I haven't found anyone with this experience with the 3.3LV6 Xterra. I'm still searching.

I will post any concrete news I have.