Additive for high oil consumption with bad rings

[Vikas]

You have not yet personally verified scored cylinder walls, right? Follow Trav and change the PCV valve before doing any more investigation.

HF boroscope is like under $66 ($80 -20%off) and the better one at Costco is at $150. You will need to verify that HF one will fit in the spark plug hole though. The one at Costco definitely will.

 

[Jerub_Baal]

The vehicle is 750 miles away where my son is in college. I have not seen it since the oil consumption issue started and won't until the spring.

He will be changing the PCV valve.

 

[wag123]

A plugged/non-functioning PVC system will exhibit the EXACT symptoms described. I have personal experience with this. FYI, If you run it too long this way it can blow a rear main seal.
That Nissan 3.3L V/6 is one tough hombre and will easily go 250k+ miles with only simple regular maintenance (including timing belt replacements, it is an interference engine). Scored cylinders? I think that the stealership fed him some bull $hit.

 

[cronk]

VG33E's are not known for pre cat failure or cylinder scoring.
I worked at a Nissan dealer about 5 years and never saw a pre cat failure on a 3.3 equipped vehicle. To my knowledge it was the 2.5 used in certain Sentras and Altimas 02 or 03. If I remember correctly, there was a software issue and they ran to rich and over heated the pre cats causing the failure, There was a computer reprogram to fix the issue.
I agree with wag123 , saw several with over 200k, still running well.

 

[Trav]

Quote:
Scored cylinders? I think that the stealership fed him some bull $hit.



Why ruin an otherwise informative post this this this rubbish?
Not every dealer is a crook or a thief nor every indy a good honest shop. There is good and bad in both.

Scored walls will most certainly demand a second opinion, i cant see why they would bother to make that up but until this has been confirmed or not comments like the stealership fed him dung are uncalled for.
Things can happen to any engine, not every one of them will make 250K easily.

 

[Trav]

Quote:
informative post this this this rubbish

Should read with this rubbish?
So much for the speech to text i put on this laptop.

 

[demarpaint]

Originally Posted By: Trav
Quote:
informative post this this this rubbish

Should read with this rubbish?
So much for the speech to text i put on this laptop.

Geez Trav, and here I thought you were trying to drive a point home! Good info about the CC that's for sure.

OP- How many oil changes did you do after you bought this vehicle? Reason I ask is the party that sold it to you guys might have been well aware of the issue before you bought it, and tweaked the oil just before selling the vehicle. I had a used car manager instruct the shop to add up to two bottles of Lucas Oil Stabliizer to trades he screwed up on that were knocking. I remember one such car coming back just after the customer did his own oil change and took that grease out of the sump. It happens.

 

[wag123]

Originally Posted By: Trav
Quote:
Scored cylinders? I think that the stealership fed him some bull $hit.



Why ruin an otherwise informative post this this this rubbish?
Not every dealer is a crook or a thief nor every indy a good honest shop. There is good and bad in both.

Scored walls will most certainly demand a second opinion, i cant see why they would bother to make that up but until this has been confirmed or not comments like the stealership fed him dung are uncalled for.
Things can happen to any engine, not every one of them will make 250K easily.

If an engine had scored cylinders it would exhibit other symptoms besides burning oil.
1. It will be low on compression and as a result it will not run right and it will be low on power.
It would be EXTREMELY RARE that ALL 6 cylinders would have scoring unless the pistons had been seized by a major overheating event. In an overheating event you would usually blow a head gasket long before you would seize any pistons. A lack of lubrication event would seize/spin the bearings long before the pistons would seize (usually the cam bearings would seize first in this engine). In a more typical scored cylinder scenario you would usually find a broken ring or rings and the one cylinder (or VERY rarely two cylinders) with the broken ring and scored cylinder wall would cause the engine to run very rough with low compression in that cylinder and a definite "dead cylinder" type of miss. Also, with that much oil running through that cylinder the plug would foul in short order.
2. It will exhibit hard starting problems.
3. It WILL throw a CEL (check engine light).
He didn't mention a CEL or a rough running engine in his description of the symptoms. I stand by my statement Trav. I would be willing to bet money that the PCV system is plugged. I have run across this same problem MANY times over the years.

 

[Bayman]

Originally Posted By: Jerub_Baal
My son's 2001 Xterra, with a 3.0 L V6, suddenly started consuming a lot of oil ( 3 quarts in 750 miles ) and the oil is very black after a short interval (~ 200 miles ).


I am thinking PCV

You might also want to check the Baffle that the PCV sits in, sometimes it can be gummed up.

 

[Vikas]

Trav does not know the dealer and neither does anybody else in this forum. Are there (at least) some dealers known to be crooked? Absolutely! There are enough documented evidence of such a practice.

I am not sure why Trav is taking offence about the dishonest dealer conjecture. If I am not mistaken, he himself is (was?) one of the inspector for the automotive repair industry. He must have nailed a few in his career.

- Vikas

 

[wag123]

Originally Posted By: Bayman
Originally Posted By: Jerub_Baal
My son's 2001 Xterra, with a 3.0 L V6, suddenly started consuming a lot of oil ( 3 quarts in 750 miles ) and the oil is very black after a short interval (~ 200 miles ).


I am thinking PCV

You might also want to check the Baffle that the PCV sits in, sometimes it can be gummed up.

Yep.
This is why I mentioned the PVC "system". There are a number of ways that the system can get clogged-up other than just the PVC valve (although the PVC valve should be the number one item on the list to replace). I have even seen the orifice in the intake plenum plugged. It could also be a deteriorated rubber PCV hose that has a leak in it and is not drawing vacuum through the PCV valve (this is pretty common).

 

[wag123]

Originally Posted By: Vikas
Trav does not know the dealer and neither does anybody else in this forum. Are there (at least) some dealers known to be crooked? Absolutely! There are enough documented evidence of such a practice.

I am not sure why Trav is taking offence about the dishonest dealer conjecture. If I am not mistaken, he himself is (was?) one of the inspector for the automotive repair industry. He must have nailed a few in his career.

- Vikas

Actually, I don't think that most dealers are outright dishonest. I DO think that there are a whole lot of so called "technicians" working at dealers that are inexperienced, lazy, and just plain inept. I have seen it many times with my own eyes.
Anyhow, we will soon find out. After they get the PCV system back to working normally on the Nissan, then we will know that the dealer gave him a bogus diagnosis. After I fixed the problem, if it were me, I would go back to the dealer and demand a refund.

 

[Trav]

Slight scoring will not always cause the symptoms you describe.
Anyone who owned or worked on Chevy Vegas knows this. The engines ran well enough (if that can be said for a Vega) and always started okay with no misfires.

I never said it couldn't be the PCV nor did the OP say there was scoring on all 6, it sure could be the PCV system but i cant state that as fact, just a possibility.
Nothing wrong with presenting all possibilities, i have no idea what it is and neither do you but there is nothing wrong with throwing every option out there.

To be perfectly honest i am just sick to death of these "stealership" comments in general.

Originally Posted By: Vikas
I am not sure why Trav is taking offence about the dishonest dealer conjecture. If I am not mistaken, he himself is (was?) one of the inspector for the automotive repair industry. He must have nailed a few in his career.


Yes i sure did on average 3-4 a day, Sat and Sun and middle of the night were not only on my list but some of my favourite times to go in with a broken down covert State car.
1200 independent shops and over 300 dealers were on the list.
I had very little problems with dealers, it was independents that had the most problems by a very wide margin.

Some dealers are shady no doubt but some are very good and i could highly recommend them and do so.
Ditto indys

 

[Bayman]

Originally Posted By: wag123
Originally Posted By: Bayman
Originally Posted By: Jerub_Baal
My son's 2001 Xterra, with a 3.0 L V6, suddenly started consuming a lot of oil ( 3 quarts in 750 miles ) and the oil is very black after a short interval (~ 200 miles ).


I am thinking PCV

You might also want to check the Baffle that the PCV sits in, sometimes it can be gummed up.

Yep.
This is why I mentioned the PVC "system". There are a number of ways that the system can get clogged-up other than just the PVC valve (although the PVC valve should be the number one item on the list to replace). I have even seen the orifice in the intake plenum plugged. It could also be a deteriorated rubber PCV hose that has a leak in it and is not drawing vacuum through the PCV valve (this is pretty common).


I am thinking that the PCV has never been changed on this car, that is just my hunch.

I remember a friend of mine complaining that his engine was down 2 quarts of oil, I asked him if he had changed his PCV, he said no, we went ahead and changed it, his original PCV was totally clogged up.

I would check everything in the PCV System, that means the hoses and any baffles.

Can you see anything inside the Valvetrain when you take your Oil fill cap off.

After we changed my friends PCV, he had no more oil loss issues.

 

[wag123]

Slight cylinder scoring also will not cause an engine to suddenly start burning a quart of oil every 250 miles. That is a LOT of oil! It would take broken piston rings and very deep scoring to do this and there would be a noticable/measurable loss of compression in the cylinders where this has taken place. Also, with the modern engine management systems that we have today, you would definately get a CEL in 750 miles if the engine was this badly damaged. The system will sense missfires that you and I can't feel or hear and an engine in this condition WILL be missfiring.

 

[Quest]

Enthusiasm's aside: my take is that if the PCV valve is faulty, you won't ended up burning 1qt of oil every 250miles (serious fogging from the tailpipe is to be observed in this case, and very pronounced). This is one serious oil burning issue, and not just a mere PCV valve can fix (can a PCV valve pass 1qt of oil through that device every 250miles? Geesh! That's drinking motor oil, man!).

No use playing guessing game until OP has the time to seriously go through the mechanical condition of this vehicle...

Q.

 

[Trav]

I have a 06 Subaru 2.5 here that used not leaked 3 qts in 800 miles. No CEL and it runs okay, explain please.
Even if it is the PCV it is still burning the same amount of oil in the combustion chamber why no Misfire or CEL?
Let see what the OP post back when he finds out for sure if the cylinders are scored, it has already been diagnosed he just needs confirmation.

BTW slight scoring along with broken oil control rings will not necessarily cause a CEL but lots of oil consumption.
That's what's wrong with this Subaru, it needs a short block.

 

[wag123]

Originally Posted By: Quest
Enthusiasm's aside: my take is that if the PCV valve is faulty, you won't ended up burning 1qt of oil every 250miles (serious fogging from the tailpipe is to be observed in this case, and very pronounced). This is one serious oil burning issue, and not just a mere PCV valve can fix (can a PCV valve pass 1qt of oil through that device every 250miles? Geesh! That's drinking motor oil, man!).

No use playing guessing game until OP has the time to seriously go through the mechanical condition of this vehicle...

Q.

No oil normally passes through the PCV valve unless the oil drainback holes in the head are plugged with sludge and the valve cover fills-up completely with oil. IF the PCV system is OK, this is another possibility that we have not discussed here. The engine will burn a LOT of oil if this happens because vacuum will pull liquid oil straight into the intake plenum. If the oil level is checked imediately after the engine is shut off the dipstick will read very low because there is a lot of oil sitting inside the valve cover. I have seen this on the Toyota 6-cyl sludge engines (all 3 of them, going back to the mid 80's).

 

[wag123]

Originally Posted By: Trav
I have a 06 Subaru 2.5 here that used not leaked 3 qts in 800 miles. No CEL and it runs okay, explain please.
Even if it is the PCV it is still burning the same amount of oil in the combustion chamber why no Misfire or CEL?
Let see what the OP post back when he finds out for sure if the cylinders are scored, it has already been diagnosed he just needs confirmation.

BTW slight scoring along with broken oil control rings will not necessarily cause a CEL but lots of oil consumption.
That's what's wrong with this Subaru, it needs a short block.

Is your 2.5L turbocharged? On a normally aspirated engine, braking all of the oil control rings is a VERY rare occurance in a street engine unless there was a defect from day one. You almost certainly wouldn't have driven the car over 100k miles and then had it happen.
An engine that is very low on compression in one or more cylinders will absolutely throw a CEL, I've seen it many times, if not from missfires then from the unusually high quantity of unburned fuel making it into the exhaust.

 

[Trav]

Turbo 2.5 but not leaking past the turbo or a busted feed pipe, 2 cylinders with busted oil control rings and light scoring. Engine is apart waiting for a new short block.
Who said ALL the rings were busted?
The engine has 117K and this happened recently, compression was lower those 2 but not low enough to throw a CEL.

I will wait and see what the OP post about the condition before commenting further, there is no point in a guessing game.