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Discussion Starter #1
Any thoughts? I’m getting 175psi compression on each cylinder. So the compression rings are ok at least, could the oil rings still be an issue? I replaced the PCV valve and it didn’t help. Would bad valve seals/guides burn this much oil? I’m losing about 3-4 quarts in 250 miles. Let me know any thoughts please, thanks!
 

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Truly dead valve guides can do it. There are ways oil can leak and be blown clean off engine bottom to not really see a leak too. If burning it you should have some exhaust smoke at that much. If high mileage motor I'd be quick to question the compression gauge too, far too many give erroneous readings.
 

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Discussion Starter #3 (Edited)
Truly dead valve guides can do it. There are ways oil can leak and be blown clean off engine bottom to not really see a leak too. If burning it you should have some exhaust smoke at that much. If high mileage motor I'd be quick to question the compression gauge too, far too many give erroneous readings.
I am definitely getting smoke out of the tail pipe. I’m currently soaking my pistons in sea foam ( in engine) in case this some how helps with any potential rings sticking. Compression tests were done multiple times and it drives so well so I’ll assume the gauge is ok. This could also be a head gasket issue right? I’m close to just biting the bullet and doing an in car overhaul, , pistons , rings, head gasket, and head work. I don’t know how to diagnose the source of oil so maybe I’ll just replace all suspects.
 

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09 Altima 3.5SE 6MT Sedan
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If you are burning that much oil, your plugs are going to be black. Are all 4 black or only 1 or 2? If 4, that speaks to some kind of intake/guide/ring issue, if only a few plugs, then more head gasket/cracked block etc.
 

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Discussion Starter #5
Hey, yes my 2 week old spark plugs are all 4 very black. I took out the upper intake (plenum) today and the entire intake system is oily. What could cause this? I know the pcv lets some oil through but this was substantial. I already replaced the pcv valve and was still burning much oil. Here are some pictures, any thoughts are welcome. What would get oil in the Intake besides the pcv hose?
 

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09 Altima 3.5SE 6MT Sedan
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Ugh. Intake can go both ways, most aren't that clean. Maybe someone else with more recent memories of their intake can comment on the relative level of filth though?

You could try inserting a 'catch can' in the PCV breather hose that loops back to the intake. You could also try plugging the PCV valve hose and disconnecting the breather hose from the intake snorkel and plugging the snorkel side. That should disconnect the whole PCV system temporarily. Run a set of cheap plugs and see what kind of build up you get in 2 weeks. Don't leave like this permanently, you'll wind up with sludge and other issues in the engine block.

The valve guides are still a possible culprit here too. They would explain a messy intake, good compression, yet more blue smoke than a diesel... I don't know if there are valve stem seals on these Nissan engines, my (very) old honda only had them on the intake valves.

They run $500ish plus gaskets and knuckle skin.

 

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Discussion Starter #7
Thanks a lot for the good thoughts. I did plug up the pcv system and was still burning oil. I agree it would be nice to know if others intakes look like this and if mine looks somewhat normal. How could worn guides cause oil to get in intake? I’m kind of at a loss as to what would cause all 4 to burn oil, oil in the intake would make sense but I don’t know how it got there if not pcv. Ugh is right, just ugh. I’m at a loss. I’m going re ring, and put a new head and head gasket in unless somebody, anybody? ... can help shed some light.
 

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Do you still have the original Precat?
If so that would for sure explain the high oil consumption.
If the consumption is that bad you are very likely too late to recover.
The issue was supposed to be resolved by the 05 year but I would not be surprised.
How many miles on it?
What oil are you running?
 

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Discussion Starter #9
I just replaced the original pre cat when I got it. The original did have deteriorated cat material inside of it. I’m using high mileage 5w 30 oil, 186k miles. I keep hearing about the pre cat issue but why would I be too late to recover? The cylinders apparently aren’t worn out enough to effect compression at all. What damage would be too late to recover from? I plan to inspect and measure the cylinders and either hone or bore them, new rings, put new rod bearings on, and a new head. What is this irreparable damage from the pre cat I keep hearing about? I’ve came back from valves breaking and putting holes through piston crowns. This is an honest question, what should I be on the look out for if the pre cat crap got to work inside the case?
 

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You can compression test 20 times and still not be right if the gauge is crap and it happens more than you think. Why you use more than one gauge once these problems show up. What I suspect now if the engine was one known for precat material coming back into engine to wear it out. If so then go by the engine acting up, the compression test may be fooling you. You may well rering to the exact same thing, if the cylinder walls are dead new rings will do nothing or even make it worse.

The precat, as with ANY first cat close to the motor can only stand maybe 10-20 minutes of oiling out before they are permanently poisoned to need another. They were made to be burning quite literally very little to nothing in normal use and any overload even of fuel can ruin them in minutes when the normal 2000 degrees soars up enough from the extra heat to melt the catalyst brick.

Did this problem show up slowly or all at once? If all at once look at anything recently done to cause it.
 

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Pull like the oil filler cap while engine is running, if dead it will have a max amount of blowby coming out of the hole.
 

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Discussion Starter #12
Ok thanks guys. “I’m going in.” Gonna get eyes on the cylinders. Wish me luck. If anybody has a magic wand for rent I’ll pay top dollar.
 

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The precat material scores the hell out of the cylinder walls. It gets everywhere throughout the engine and is like having sand inside.
How does the engine sound, and run?
My 03 had the precat issue and I removed it at 200k. The oil consumption was terrible. At least a quart every 500 miles.
I drive it hard and now have about 240k miles on it and the consumption has dropped quite a bit over time.
I now go through about a quart a year.
 

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Discussion Starter #14
Very interesting. Mine is burning about a quart every 50 miles. I’m not kidding. But it runs and sounds soo good man. Runs so well, burns so much oil. I’m going to attempt to remove the pistons and cylinders with the engine in the car by dropping the upper oil pan and taking the head off. I’ll inspect and go from there. Hopefully I can just hone the sh** out of the cylinders, throw new rings on, new rod bearings and be lucky enough to see 240k like you.
 

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You are going to have utter fits keeping honing grit from getting into the crank bearings. The only way to do that right is yank engine. And if the bore is too big from wear the oiling will still continue.
 

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Discussion Starter #16 (Edited)
You’re right on all accounts. I’ll try my best. If it looks too bad to hone I might pull the engine and do it right. Already in the middle of another build though. This is a project car I paid $450 for , it didn’t drive over 30 when I got it, replaced the exhaust manifold and it purred. Was told it had a bad head gasket. Thought I got lucky, apparently not. it is sure providing a great introduction to nissans for me. ?
 

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anything is worth a shot.
If it was not for the precat and the butterfly screw issues I would say these engines are bulletproof.
I have over 500k between both of our Altimas. Both purr. Never been opened up
 

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Discussion Starter #18
Right on that’s good to hear, ill definitely lock tight those screws and gut my new cat. Hope to get this thing on the road again. I’m actually pretty optimistic. After all the symptoms I’ve seen and diagnostics I’ve tried I think it MUST be worn out cylinders. Probably grooved and letting oil past the control rings. That oil would be pushed up by the compression rings and actually help seal them and perhaps contribute to my good compression readings. Or as somebody mentioned earlier I may have a crap gauge, but the car was moving pretty good. I keep thinking about the oily intake though pictured above .. because if oil was somehow being sucked up there it would explain having all 4 cylinders burning oil. I replaced the pcv and have a factory valve cover with good baffles. So I don’t know. I’ll be sure to post updates for anybody who may come across this on their Altima. Will have the head off tomorrow.
 

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Discussion Starter #19
The cylinders are not bad by visible inspection. No scratches or any signs of grooves. What the heck! Can’t find anything that would be a reason for this much oil burn, unless the rings are crap. Gonna remove the engine. Might just swap at this point. If I can’t find a problem I don’t know what to fix. Dang
 

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Trade it or sell it. Its a defect in the engine design. Excessive oil consumption. My engine blew in 2014 after 115,000 miles. Served nissan about it but they just gave me the run around. The engine will start to tick faintly at highway speeds and it will run fine until it gets trashed. Mine sounded like change in a tin can the day it gave out. My mechanic pulled 5-7 gallons of oil out of it, how? Idk but google it 06 altima excessive oil consumption.
I researched it because they didnt have my EFN as part of the recall but after finding the recall report from Nissan online my EFN was a part of this defect and they wouldn't honor it. They said I removed the engine before taking to nissan so the cost was on me not them, i called them before removing it and all they said was it was past my warranty so wtf was i supposed to do? My car was in my moms back yard for 7 months waiting for my new engine (i paid for everything). This engine design is flawed every which way possible. From the engine to the pre-cat issue. If you decide to keep it gut out the pre-cat or buy straight pipe headers and gut the 2nd cat underneath. I can tell you that if you hear ticking youre past the fixing point and it will blow. Good luck.
 
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