Metal Flake in Oil - Low Oil Pressure - Next Steps?

zisfor_nizmo

Hello All!

I'm in a bit of a pickle, and am unsure what the best course of action is here. I have a 2009 370z with just over 94,000 miles now.

At my last oil change (4,000 interval). I noticed metal flake in the bottom of my oil pan, I have attached pictures of this. Big red flag. Car was immediately parked for the foreseeable future, oil from that change was sent to Blackstone immediately. For reference, I've done 2/3 oil changes this year (Including a trip to TOD and a Track day) with clean oil every time.

Oil analysis report came back for the large part normal, no crazy amount of metal in the 10-15 micron range that Blackstone Tests in. Aluminum is slightly elevated (I believe the shavings to be aluminum as well). Oil Analysis report is attached as well.


Following the Report, next step was an oil pressure test, this is where I got a big shock. I was reading about 6/7 psi at idle and about 24 psi at 2000 rpm before reaching operating temp (measured at about 145/150 degrees F). Car goes back to being parked.

I plan to Borescope to take a look at the Cylinder walls. My guess is this is where the metal flakes came from. This is yet to be done.


My thinking here is that odds are, low oil pressure caused by the gallery gaskets going out is what caused the metal flake in my oil. My oil pressure is reading very low but I did not get a CEL or oil pressure light on my dash at any point. The car also, to the best of my knowledge, doesn't appear to be running differently or making any noises (during oil pressure test).

What is best course of action here, should I get the motor torn open to confirm/replace the failed gallery gaskets? Is it even worth doing this on the motor after seeing the amount of metal in the oil, oil analysis shows there isn't much slow wear happening on internals? Or Should I be looking for a replacement motor/rebuild instead and completely chalk the current motor.

Looking for advice here from some Z owners who have experience in this area.


- A very concerned Z owner

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JARblue

I think your analysis of the damage being cause by failing gallery gaskets is probably spot on. Your question of whether its even worth the tear down is the real kicker. When I did the gaskets I also put in a CJM oil pan; I found bits of gasket material in my oil pan but no metal shavings. To see that amount in the drain pain would definitely be concerning to me. Other more experienced individuals may have better insight.

You need to have in your mind what your bottom line is. If you like the car and have the funds available, then it may be worth a tear down to check the extent of the damage. Otherwise, you may need to be prepared to bail

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Ben370

Oh wow that's half the psi I had and my gaskets were decently blown. So change those and timing while you're at it.

Yeah teardown or sell it.

I'd start with the boroscope (do spark plugs too since you're almost at the rated 100k) then pull oil pan and valve covers then go from there.

zisfor_nizmo

Both great points, I definitely will run the borescope soon to see what it yields.

I guess my biggest question right now is: If I repair the gallery gaskets on the current motor, what are the odds it will it run for maybe 40-50k without catastrophic failure?

If there's no point in repairing, a replacement motor seems logical from the get go. But the oil analysis results lead me to believe if the pressure issue is solved, the motor may still have some life left in it.

I am also pretty sure I know exactly which short drive the metal flaking resulted from, and it was right before I changed the oil and discovered it. I don't believe the engine ran for an extended period of time after the gaskets blew, but there's really no real way to tell given the obvious wear that has occurred.

SG4247

Low oil pressure generally wont show up on the cylinder walls.

It will be in the main and rod bearings and crank. Sometimes wrist pins.

If the motor is not knocking now, it is possible it can be saved with new galley gaskets.

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100 shot E85 - 11.589 @ 117 mph
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Spooler

Replace the gallery gaskets and remove the upper oil pan. Have the shop spin in some new Rod and main bearings. As long as the crank looks good, you are good to go. If the crank has some wear, not good. Rebuild time.

Tractionless

I wouldn't chance the engine being good after repair. If/when my 2010 needs galley gaskets I'll be doing a used low mile 2014+ engine.

As they age it seems these cars require an oil pressure gauge to catch the oil psi drop prior to causing collateral damage.

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Toys Not Tots

zisfor_nizmo

Bringing some closure to this thread. Over the course of the last 6 months the the Z got a replacement motor out of a 2012+ g37 with about 60k miles on it. The engine itself was pretty clean when we were taking it apart and it got new gallery gaskets, hardware, and a billet oil pump from boundary engineering. It also got Poly motor and trans mounts as well as ISR long tubes but not directly relevant, did new spark plugs as well.

The new engine has about 1.5k miles on it, oil analysis is being sent out to Blackstone to confirm everything is good, otherwise the motor feels to be healthier than the one we pulled out of it before failure.


Interesting bit for the folks who want to know what the hell went wrong: I took the old motor home and completely stripped it down, and I was baffled there was no visible damage anywhere. The bearings didn't look too bad and honestly the rest of the damn motor was clean. While cleaning out the valve train and removing the cams, I finally found some damage. Portions of the outer edge of the valve spring retainers were missing on more than one retainer. I'd say probably 5 or 6 of them had varying amounts of material missing. So she was real damn close to dropping a valve I'd say. I will post some pictures of this in the next post.

Currently car just had rear camber arms, toe bolt, alignment, and 285 square Indy 500 tires done. Looking to get tuned by Seb soon. To be done in the next few weekends: Pads, Rotors, Stainless lines, Brake fluid, Diff fluid and Trans fluid.

zisfor_nizmo

Forgot the mention, very important, AEM oil pressure gauge! Deleted the oem dummy light because it is pointless.

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zisfor_nizmo

The largest chucks of metal found in oil pan:

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SG4247

Wow!

Did not expect that. I dont get how that could happen on a 90k mile motor. I know these engines will go 200k plus miles with proper maintenance.

So what would’ve caused retainer failure, as I never have heard of an issue with OEM retainers.

We’re the broken retainers all intakes?

__________________
NA on E85 - 12.402 @ 112 mph
100 shot E85 - 11.589 @ 117 mph
JWT C2 cams rev Base Circle & Titan Valves

Rusty

That's a new one. I've seen broken retainers. But to have them wear like that, no.

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zisfor_nizmo

I ran out to check the heads: 3 valve spring retainers were broken each from the middle cylinder’s intake side (2 in one bank 1 in the other, the 1 only has about 20% of it left….ready to drop)

I’m not entirely sure what caused this, googling said an over rev could have caused it. I think I’d remember if I money shifted the car…. Also coinciding with the gallery gasket failure seems bit too coincidental.

I think some combination of no oil in the heads, a build up of heat, and some stress lead to the the retainers snapping off. Those fragments sheared and shredded on their way to the oil pan where they sat all polished and shiny until we found them.

I also haven’t read anything about something like this before. I don’t believe this is a common failure point. My mechanic works on a ton of 300zxs, 350 and 370zs, he’d hadn’t seen anything like this either. At least now we know, if you see pieces shaped like that, it’s you retainers

Spooler

First year engine build. You can get all kind of strange stuff that happens. Valve float can tear the crap out of stuff. If you money shifted it, that is probably when it happened. You had valve float.

NissanTracker

Sounds like a Gallery gasket issue. My HR nismo (2007) went at 35K miles. I was lucky to catch it because of the factory oil pressure gauge.

How and when they go really depends on the driving habits. Heat cycles with high pressure (high reving)... the paper gasket eventually starts to absorb oil and then eventually break apart.

Someone that just daily drives versus someone that likes to bounce off the rev limiter, or tracking the car are some of these habits i'm talking about.

I just pulled a buddies 2012 370z engine out (manufactured in 2011) due to gallery gaskets. He purchased it at 30K miles. I put a scope down and gallery gaskets were great. Oil pressure normal. After 10K miles... boom. Tossed a rod. He increased the rev limiter to 8K and was only a matter of time. And yeah... he loved bouncing off limiter.