maloy

I am having a very serious issue with my G37, and any help or advice would be appreciated.

Here is what happened tofay:

As I am going on a highway and start accelerating to pass and the car revs but refuses to go faster. I immediately get off the road, and as I do I suddenly hear very loud clunking/knocking sound coming from the engine bay, which gets much louder and more frequent as I try to accelerate. The sound seems to be coming from underneath the engine bay. The knock is loud even at idle. I am not too knowledgeable about the tech stuff, but I thought that it may be a rod or a piston. Needless to say, I got the car towed to the dealer tonight, but they are closed so I won't find out until tomorrow, but the tow truck driver also thought it was the rod.


So here is a brief story to what lead up to the problem:

The car has about 70,000 miles on it, and I just got it back from a dealer after having a CEL code (0021) and the car going into limp mode at 2,500RPM a week ago. All they did was change the gasket rocker covers and test drive it, but found nothing else wrong. Just days before that, the car had an oil change done, at the dealer.

And that was the fourth time I had a CEL with the car going to Limp mode on this G37, which started when the car had 58,000 miles. The first issue was related to oil pressure, and from what I remember it had the gaskets, valve covers, solenoid and ECU all replaced under warranty due to these problems.

I had the car since new and have always been timely with oil changes (3,750) and all other maintenance, and I used Pennzoil Platinum and then Ultra if that matters. I also periodically check oil between changes, and there were never any problems.



Can anyone diagnose the likely problem, and help me understand if all the other problems since 60,000 might have just been an indication of a bigger engine issue that manifested itself now? What are the chances of this happening on a 70,000 mile car that has never been raced, modified, or abused? Would something like this need a rebuild or replace of the block? Am I right in guessing that the initial oil pressure problem at 58,000 miles caused some damage, which eventually resulted in a thrown rod, or whathever this is?

There is just no way this current issue is not related to the previous ones. The car may just have come off warranty, but I plan to fight this hard if they try talk their way out, since it all started before 60,000. I already registered the ongoing issues with Infiniti Corporate previously. This has been a freakin nightmare, and I have a feeling it is just getting started.

RISKY GUY

iTrader: (9)

The best advise, if your car is all oem I would press that dealership hard.
If your trouble started before the original warranty expired, they messed up or misdiagnosed.
All you need is service records, you should be fine.
Also they have something called, customer good will.
Had an entire vhr block & assembly replaced by dealer.
My car was modded up, they fixed my g,so you'll be ok.

jaykellogg

You should be OK. If the problem started before the warranty expired it should still be covered. If you get your oil changes done at the dealer and the issue is oil related you should be golden. You could have a rod bearing going, a broken valve spring, or a timing chain tensioner problem. Assuming it is a rod bearing, I would want to see a short block or long block replacement. The best would be a full engine replacement.

Keep us informed.

maloy

Thanks for the info. It does appear that I am not going to have issues with the warranty covering it. What is the difference between replacing short/long block, and full engine replacement? I just want all possible root causes gone, and no damaged components remaining. If this is a broken valve spring, should I settle for just a regular repair, or is there likely more issues down the road, seeing how this is not the first problem?

To better describe the noise it was like a loud metalic sewing machine and the car pretty much lost all power, although the engine would still start. It still seemed to have normal oil level in it, but then the oil change was a week ago.

daonlyillwiz

iTrader: (2)

Maloy, if it sounds like a bunch of marbles in a can and gets louder as rpms get higher then that means its a spun rod bearing. This typically happens due to oil starvation/incorrect oil type/incorrect clearances/contaminated oil/over revving.

Long block: includes short block (block which has rods/pistons/crank) and cylinder heads(valves cams etc...)

Shortblock: is just the block (bottom half with pistons/rods/crank)

Typically in a situation like this they would have to inspect the cylinder walls for any scoring caused by metal shavings being thrown around by the spun bearing.. In most cases they would replace the block because if the walls are scored up its not cost effective for them to do all the machine work necessary to bore the walls out and get oversized pistons etc... In your case you should be getting a new bottom end, new crank, rods, pistons. As far as the heads go im sure they will just inspect and clean them incase any shavings made it up that far.

You will have a 70k car with a 0mile engine, congrats!

maloy

Thank you, that is exactly what is sounds like. The dealer has looked at CEL codes showing oil pressure problems before, so how likely is it they missed the problem then? By over revving do you mean having the engine at or near the red line for prolonged time? My G37 is an auto and I almost never use the manual override feature, so I can't see that being the problem. What would cause oil starvation considering I am not racing and oil level seems to be normal?


If they don't replace the long block, how likely am I to have issues in the future from any possible problems caused by this?

daonlyillwiz

iTrader: (2)

Yes, approaching redline and holding it there for a prolonged period of time normally will heat up the oil and thin it out which will increase your risk of engine damage.

Well if you had oil pressure problems before than that can definitely be the root cause of this problem...oil starvation can be caused by several things:
1-underfilling oil/low oil level
2-incorrect oil weight (too thin)
-if over revved with this condition will result in heating up the oil which
breaks it down and makes it even thinner causing the metal (in this case connecting rod bearings to heat up due to friction and expand which will cause it to spin and mess the crank up and produce metal shavings and throw that into the oil which will travel up the passages/oil cooler and cause further damage through the engine.

3-bad oil pressure relief valve can be wide open allowing all the oil in the pan to get sucked out and thrown into the top of the engine (cylinder heads) which will as a result leave the bottom end rotating assembly with little to no oil resulting in oil starvation which will then result in the ending for reason #2.


As far as future issues after short block replacement i dont see why you should have problems as long as they thoroughly inspect and clean the cylinder heads which im sure they will as well as replace the oil cooler(if one exists) you should be fine.

ALWAYS CHECK YOUR OIL LEVEL EVERY OTHER WEEK-just incase.

Rad_Slinger

iTrader: (12)

i take back every bad thing i've thought about you. great answers in this thready by you


learn something new every day.



still gonna call you lilwizzer though

daonlyillwiz

iTrader: (2)

lol thanks DOMO

maloy

It looks like they will indeed replace the engine block! I don't know whether it is short or long block yet, but in any case that is good news. The dealership has also been cooperating very well, and transparent about what is going on, which I am happy with.

One lingering question I have, is whether anyone knows if in a case like this Infiniti will place a brand new short block, or will only give me a refub/used one, which I definitely hope is not the case. Does anyone know if Infiniti ever replaces an engine for one that is not straight from the factory?

Reading about the VQ37 engines online a bit, it seems like oil consumption and engine issues related to it is not something unheard of. Has anyone else here had their block replaced due to this? What are the chances that the new block will be improved in some way?

Buckeye G

iTrader: (4)

If the dealer is doing it under warranty then it will be new from the factory.

RISKY GUY

iTrader: (9)

The motor will be 100% new down to the new exhaust manifold bolts.
Infiniti does not do rebuilds. As far as reusing cylinder heads,not Likley since your marble sound could be chunks of piston or rod.
Plus, why are they going to take a chance with a new block & trying to recycle heads only to have you right back. With them eating the $.
They will do it once just make sure when you get it back no vaccum leaks.
That was the only mistake made, plus guy to Rock a loaner for 3 weeks.
Your getting a new vhr long block assembly, trust me on this.
I blew my motor with piston #5 desintigrating inside block.
Also you will benefit from updated software.
Also if you plan on any bolt ons, now is the time to do it while the motor is out.
Enjoy your new motor, you just made a nice improvement to your cars value.
Zero miles brandy new.

boxtwo

Old thread, but what year was this G?

G37 ginz

I have a 2012 g37x I put k and n intakes and I draggy piped only the mufflers I was on the highway and the motor completely blew if anyone has an answer to why this could have happened please direct message me I believe it could be rod/ piston the dealership is looking at it now

slartibartfast

iTrader: (7)

You're talking 1960's oil. Since the SE standard was adopted, base oil and additive breakdown has become a non-issue for cars that get regular oil changes.

Um, no. The excess oil will drain back fast enough to keep the pump from starving. And the passages are sized such that oil distribution is not biased towards the top end as you describe.