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Discussion Starter #1
I'd like to know if anyone had this experience and also your opinion as to whether a repair rather than replacement is adequate.
I took my Z51 with about 1800 miles on it to Road America for a high performance driving experience where you drive the track in 20 minute sessions.
I drove two sessions in the morning without incident. After lunch I started a 3rd session and at about 4 minutes, 5 miles got a low oil pressure, turn off engine message.
There were no other warning messages.
I got off the track and turned off the engine and radiator fluid was boiling out of the overflow.
I got the car trailered to my dealer.
They said three connecting rod bearings were "melted", but the oil pump pressure was fine.
Apparently Chevy wants my dealer to just replace the bearings, but my dealer is trying to get Chevy to authorize full engine replacement.
Also, the Chevy tech rep said something like the rod bearings might have been slightly too thick and that this caused the low oil pressure.
Several questions...
Has anyone had any similar oil pressure problems?
What do you think about the theory that thick rod bearings could cause low oil pressure.
If low oil pressure caused three rod bearings to melt, how likely is it that there is other more subtle damage?
If my dealer is unsuccessful in getting Chevy to replace the engine, what options to I have?
 

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Did you do the oil change as recommended in the manuals? I believe its to 15w50.
 

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Bearings too thick would not be a cause of low oil pressure. Too thin or too much clearance would. If 3 bearings are shot, the crankshaft has damage, all of the other bearings likely have damage. The oil pump has pushed powdered bearing material through the oil system. Cam a roller lifters may already have damage. The only way to know is to go through the engine - in my opinion. Had a similar problem on a LS2 (different cause) and ended up replacing almost everything to make it right. Since it happened during track driving it might get a little sporty getting them to honor the warranty.
Good luck with your quest to get it repaired/replaced.
 

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madmax6252, sorry this happened! I hope everything works out. Please keep us posted.
 

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Question??? Car has Z51 "track" package on it. It has a "track" mode dial in it. It has instructions for use at the "track". IMHO, u we're using the car as it was engineered and advertised and sold and marketed to do. Seems like the track shouldn't have anything to do with it. Getting a new motor, that I think, you should get is all together different question, good luck. PS, I got mine to 147 mph going to an emergency the other day and it was just starting to breath nice. Problem is, I live close to work.
 

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madmax: Can we assume that your dealer has already thoroughly gone through the motor and is satisfied there is no other damage? I would think that the crankshaft would be damaged, not to mention that the cylinder walls of the cylinders with the failed bearings might have been scored. If not I would not feel very good about that approach, but if they are going to warranty the work maybe that can be an option. I would try to get a new engine though.
 

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Discussion Starter #7
All, Thanks for your comments.
Here's some more detail and responses.
I saw the note about 15-50 oil but figured (perhaps wrongly) that the regular oil should be ok for a 20 minute session. However, I was a quart low and topped of with 1 quart of 15-50.
I need to get more detail from my dealer as to exactly what and how carefully they checked other things beyond the three rod bearings.
I have not talked directly with the dealers tech guru, but will try on Monday. The service consultant said the oil was "fine", but I'm not really sure what he meant by that.
Both the dealership owner and my salesman called me and said they will push for replacement, rather than repair, so I feel good about the dealership.
Sriegle, I completely agree with you that being on the track should not do anything to void the warranty and that has never come up as an issue.
As I said to the dealer, I went to the Ron Fellows school in Vegas and they put 10000 to 15000 on their track cars before the re-sell them and I did not drive my car nearly as hard as I drove their cars.
Please if anyone hears of any C7 oil pressure issues let me know.
I'll respond back as soon as I hear more.
 

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I saw the note about 15-50 oil but figured (perhaps wrongly) that the regular oil should be ok for a 20 minute session. However, I was a quart low and topped of with 1 quart of 15-50.
Did you check the oil level before each session? Or was the level a quart low at the beginning of the day?

What kind of oil did you have in your Z51?

Wishing you luck with the warranty replacement. I drove my C6 at Road America and hope to drive my C7 there as well. While I have a "base" car, I will follow your story closely because I am now curious if I need to change to 15-50 before such an event.
 

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Not sure if I missed something here, or I've just misunderstood what's been said. Doesn't the manual call for 5W30 weight oil? And then you added 15W50? I'm not sure about you guys, but I was taught by Pennzoil to NEVER, NEVER NEVER add or combine different viscosity oils.... The notion of one quart of 15W50 being added to 5W30 raising the viscosity of the oil doesn't work out that way. It can have the opposite effect or even worse..... Just sharing what I was told my one of my sponsors...
 

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I would NOT run the cheap Dexos blend as it cannot protect the internals like a good full syn. If this took out multiple bearings (rods dont melt, so they told you wrong or misunderstood). I would want an entire long block as Chip states....metal debris went through the entire rotating assy and look at the rod caps....they will be blue and discolored and the crank at the very least needs replaced. They may insist a short block only but I agree w/Chip. Push for a new longblock. Try and get pics to post as well.

Only run a good full syn if your going to track the car......I have no faith in the cheap DEXOS blend oils as we see this all the time in here with the V6's in late model Camaros and Cadillacs:
 

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Discussion Starter #11
My primary concern and reason for posting is the extent of damage done to the engine and whether replacement of just the rod bearings is adequate.
I already expressed my concern to the dealer that the integrity of the engine has been compromised beyond the rod bearings and given that they're pushing for full replacement, it would seem they agree. Comments from Dasyatis, Chip and Tuner Boost are consistent with this as well. But no one has put forth an explanation as to why the oil pressure went low in the first place. (Other than the Chevy reps too thick bearing theory, which I believe is pretty illogical.). On the subject of oil weight, which I guess might be a cause, here are some comments.
First Mobil 1 website says there is no problem with mixing viscosities. Is There Any Harm to Mixing Different Mobil 1 Viscosities?
Second, the car still had original oil the day before track day, just one quart low after 1800 miles of regular driving. I topped up with one quart Mobil 1 15-50. Tuner Boost I believe you are ok with Mobil 1 because its full synthetic, dexos rated and what Chevy recommends? If 5-30 weight oil was the culprit, why didn't I have a problem with one of the first two full sessions with about 25 miles each (six laps) instead of the last partial session of just one lap? However, once the engine repair/replace issue is resolved, I'm going to push to get clarification of exactly what type of track events require 15-50 since the manual is not specific on this point. Also, I'm going to push for more details today as exactly what the dealer has looked at in terms of damage, but believe that even if nothing is visible, the metal fragments and high heat have made the engine less dependable and probably shorter life and I should not have to have the constant worry of when it might break down again, despite the warranty and in particular since no cause for the low oil pressure has been identified and fixed.
 

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Why the low pressure..
Too much bearing clearance
Oil pump too much internal clearance
lifter failure
Oil pump pickup fell off
Oil pressure relief valve failed open

No real way to diagnose such a failure without getting your hands dirty with the insides of the engine.
 
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Discussion Starter #14
All,

Just heard from my dealer. They did more looking at the engine and found problems with the main bearings.
Once they shared that info with Chevy, Chevy authorized full replacement of the engine.
However, there is still no further understanding of what caused the original low oil pressure.
I did not tee up the issue of when its necessary to swap 5-30 for 15-50, but will pursue that AFTER I get my car back!
Thanks again to for your input on this!
 

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Dasyratis,

Thanks for the culprit list! Do you have any thoughts on whether 5-30 oil might be the problem?
In my view of the world, no. At best it might be a contributing factor (like 5%) but something else had to either be wrong or fail. Of course a tear down and dtailed inspection of each part is needed to find the root cause.

As en example, my ex LS2 developed a no oil pressure issue at about 50k miles. Through careful inspection of the parts I found a defect, from the factory, that was the root cause. In my case an untrimmed piece of flashing was folded over on the oil pump cover plate and just to happened to align with the outer oil pump gear. This caused gapping of the cover and a side load on the gear which resulted in it slowly eating into the housing which also sent aluminum debris micro powder) through the engine. This is not to say yours is the same or even similar but that attention to detail is key.
 

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Why the low pressure..
Too much bearing clearance
Oil pump too much internal clearance
lifter failure
Oil pump pickup fell off
Oil pressure relief valve failed open

No real way to diagnose such a failure without getting your hands dirty with the insides of the engine.

Excellent list....I would go one further, oil pump failure can be as simple as casting flash causing the pressure relief valve to stick (most common failure we see in regard to oil pressure issues on new LS engines) or the O-ring getting pinched/cut when installing the pick-up. (we have seen this on occasion direct from the factory). I would put this at the top of my list as the TSB's have been out since 2010 on this very issues:
Oh NO !!!!! TSB on the LS3 oil pump - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums - Camaro5.com

On the lifter failure, that is also what we see on occasion where the needle bearings fall out and become ingested. I have rarely seen any get the bearings wrong from the factory......but just had an engine in a shop put .010 over bearings in a stock journal sized crank and it would not turn over (lucky for the owner we tore it completely down to diagnose).
 

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In my view of the world, no. At best it might be a contributing factor (like 5%) but something else had to either be wrong or fail. Of course a tear down and dtailed inspection of each part is needed to find the root cause.

As en example, my ex LS2 developed a no oil pressure issue at about 50k miles. Through careful inspection of the parts I found a defect, from the factory, that was the root cause. In my case an untrimmed piece of flashing was folded over on the oil pump cover plate and just to happened to align with the outer oil pump gear. This caused gapping of the cover and a side load on the gear which resulted in it slowly eating into the housing which also sent aluminum debris micro powder) through the engine. This is not to say yours is the same or even similar but that attention to detail is key.
Sorry I missed your post!! This is exactly the most common issue we find to bearing failure....your dead on correct. When building LS engines it is easy to deburr the internals and blueprint them to avoid this.

Really have some good knowledgeable members here in this thread that actually appear to have been inside these engines.
 

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All,

Just heard from my dealer. They did more looking at the engine and found problems with the main bearings.
Once they shared that info with Chevy, Chevy authorized full replacement of the engine...
Good to hear! Let us know how it all goes back together with the new engine.
 

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Sorry I missed your post!! This is exactly the most common issue we find to bearing failure....your dead on correct. When building LS engines it is easy to deburr the internals and blueprint them to avoid this.

Really have some good knowledgeable members here in this thread that actually appear to have been inside these engines.
After thinking about it and reading additional posts I began thinking oil starvation being the primary culprit. Pretty elementary conclusion I may add..... I recall going through a period of buying into the latest greatest "Tricks of the week" oil filtration systems which did nothing more than restrict the amount of oil to the crankshaft and internals (Mains and Rods), which resulted in catastrophic failure. Today, I use the good old proven spin on filters as used in this particular case. So, the only other area that could have possibly have failed to supply sufficient oil would have been the oil pump itself. Dasyatis and Tuner Boost have brought up some incredibly insightful points as to what caused the oil pump itself to fail. I'm sure Tuner Boost can attest to this, but I've ALWAYS built all my own engines and assembled them meticulously checking all the clearances and chamfering, deburring and polishing practically every edge and surface on the inside of the engines. All this takes a great deal of time, which the manufactures don't have allot of if they want to make any kind of profit.

I considered buying a ZZ4 engine from Chevrolet for a "Street Project" I was working on for myself, but decided against it regardless of the 3-year 36,000 mile warranty because none of the oil passages on the crankshaft were chambered and the factory tolerance was 8-grams out on the balance on one we were hired to go through for a customer. I'm sure it's fine for the average person and they provide trouble free service as well, but it's not for me. Sorry for getting off topic here, but the point I'm trying to make is some of us are bound to run into this from time to time, which is exactly what the factory warranty is for. I'm certainly not going to pull the engine out of my 2015 Z06 upon taking delivery, I don't want to know and I'll have no reason to check it.

Glad to hear GM has decided to replace the entire engine. I would have been deeply concerned if they didn't.
 

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After thinking about it and reading additional posts I began thinking oil starvation being the primary culprit. Pretty elementary conclusion I may add..... I recall going through a period of buying into the latest greatest "Tricks of the week" oil filtration systems which did nothing more than restrict the amount of oil to the crankshaft and internals (Mains and Rods), which resulted in catastrophic failure. Today, I use the good old proven spin on filters as used in this particular case. So, the only other area that could have possibly have failed to supply sufficient oil would have been the oil pump itself. Dasyatis and Tuner Boost have brought up some incredibly insightful points as to what caused the oil pump itself to fail. I'm sure Tuner Boost can attest to this, but I've ALWAYS built all my own engines and assembled them meticulously checking all the clearances and chamfering, deburring and polishing practically every edge and surface on the inside of the engines. All this takes a great deal of time, which the manufactures don't have allot of if they want to make any kind of profit.

I considered buying a ZZ4 engine from Chevrolet for a "Street Project" I was working on for myself, but decided against it regardless of the 3-year 36,000 mile warranty because none of the oil passages on the crankshaft were chambered and the factory tolerance was 8-grams out on the balance on one we were hired to go through for a customer. I'm sure it's fine for the average person and they provide trouble free service as well, but it's not for me. Sorry for getting off topic here, but the point I'm trying to make is some of us are bound to run into this from time to time, which is exactly what the factory warranty is for. I'm certainly not going to pull the engine out of my 2015 Z06 upon taking delivery, I don't want to know and I'll have no reason to check it.

Glad to hear GM has decided to replace the entire engine. I would have been deeply concerned if they didn't.
When a big purse or a Championship is on the line.....taking the steps you do.have make the differences between success and failure. We consider this "standard" with any engine build, and many old timers and all successful race teams do these....but so many of the late model muscle shops today just assemble parts as they come.
 
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