I need help diagnosing this sound my car started making yesterday upon a cold start. Rattling coming from within the engine, I'm sincerely hoping it's not a rod, and just a valve needing to be tightened up or something.


Car is a 2006 350z Base with 100k miles on the Odometer, short block was replaced at 50k miles due to oil consumption (haven't had much of an issue since) by Nissan under factory warranty. I religiously change oil @4k miles with fully synthetic mobil 1 oil and make sure to top off oil @2500 miles driven.

I know these engines are faulty but, as far as I know that was just for oil consumption. I do NOT drive the car hard. I baby the crap out of it.

I apologize it's so dirty by the way.... I usually keep my car nice and clean but haven't had time to wash it recently lol

 

Ya know, it's almost impossible to accurately diagnose a sound just by watching/hearing a clip. Guesses from behind a keyboard are just that. Beyond taking it to a skilled tech, I'd suggest doing a UOA and seeing what the results are to narrow down the possibilities.

 

Definitely sounds like valvetrain from the vid, though hard to tell. Does the sound increase with RPM? Does it go away completely after the first start?

 

Thanks for the feedback guys. I plan to take it to Nissan tomorrow. I have not driven the car at all anywhere so I don't know how it performs during a drive. However when I rev the engine, the sound does persist.

I am thinking it can also be my spark plugs. I may have a blown plug. The reason I think this is because I haven't changed the plugs since I got the car at 50k miles. And I do not know if they change spark plugs during a short block replacement. If they kept the original plugs, then it makes complete sense that after 100,000 miles I have a blown spark plug(s). The car has been struggling ever so slightly starting recently, which makes me more suspicious of it. I doubt its my battery because I'm running an optima red top.... those things are powerful as hell, and my alternator is operating just fine according to my voltage meter. No check engine light of any kind as well which I find odd.... There was definitely vibration upon starting it two days ago, a lot of vibration. Another indicator it may be my spark plugs. I have some NGK spark plugs I've been meaning to install too.

In any case I'm going to have it checked out tomorrow and I hope to hell it's just spark plugs. It makes no sense having a rod issue or valve issue when I've meticulously maintained the engine on this car.

It sucks that the video quality came out like that - you can hear it so much better on my iPhone. How can I upload the video on higher quality for you guys?


p.s - moderator I'm not sure if you need to move this thread to maintenance and repair, I realized I may have posted this in the wrong place and I apologize for that.

~ Mike

 

Well, okay, this is awkward.


Nissan had my car for over 48 hours, before I finally got fed up with the poor service I was receiving and went to get my car back.

Here's what they told me:

1. Engine needed additional 3 quarts added, low engine oil. WTF. No.

I checked my dipstick in the morning prior to taking it to them, and the engine oil level was reading dead smack in the center of L and H @2000 miles since my last oil change. The dipstick, if I'm not mistaken, READS ONE QUART OF OIL BETWEEN H AND L, AM I CORRECT? So if they DID add oil, it would be NO MORE than HALF QUART. According to the chart in the Revup Oil Consumption thread which is a sticky - at approximately 12mm below the H mark you've gone through about half a quart of oil. Can someone PLEASE confirm this.

2. They told me my spark plugs were ok at first. The next day they tell me they're worn out and need replacement, and that there's some oil inside the #4 and 6 ports (whatever they're called) - I may believe this, as my car does consume just under a quart per 5,000 miles. This will never stop, the engine is faulty. No use replacing a short block TWICE - You're replacing faulty engine components with the same faulty components. The service manager did mention a long block might be required if my consumption levels are "this bad". Ummm, buddy, your technician didn't add 3 quarts.

I had them install my NGK Laser Platinum spark plugs at the cost of $240. They were initially gonna charge me $360 - I told them hell no. Price was adjusted.

3. If my engine oil level was so low, why did it take them 48 HOURS to tell me this??? Whats the first thing a mechanic will do, probably every single time he services a car, especially when you tell them MY ENGINE IS MAKING KNOCKING NOISES AT A COLD START......... Duh!! They'll check oil! If my car was low on oil, they'd have told me from the first day!! But why did it take 48 hours for them to diagnose a low engine level? Which leads me to believe it's all BS.... especially since I measured my oil level in the morning before starting the car, before I took it to them. The reality is that they don't know what's wrong with the car, so they came up with some stupid crap to tell me. Took 48 hours for them to tell me my spark plugs were bad, and my car had low oil levels.

I need to start the car in the morning to see if its still making the noise.

Updates soon

 

Gosh man sorry to here. *hear
Try a different dealer

 

BUSTED!!!!!!!

So here's how I absolutely know for SURE the dealership is jerking my leg.

The technician claimed he added THREE QUARTS OF OIL to my car because it was short. Well, if he added three quarts to top off my car due to "low oil levels", how do you explain my dipstick reading the exact same levels before I dropped it off hmmmmmmmmmmmm???????? I would think a technician would know how to top off oil to the H mark!!!!!!

I mean, what the heck is this?! by the way yes the car sat overnight and I took the reading prior to starting the car - which by the way there was NO NOISE. It was an absolute flawless start. My spark plugs could have indeed been the issue, because if they were not replaced @ 40,000 miles when the short block was put in (I looked at my service record and it was indeed 39,xxx miles I accidentally said 50k), then they'd be 100,000 miles old now and completely worn the hell out. Even if they were replaced, they'd be 60k miles old now and need replacement ANYWAY.

So I have no clue, absolutely no clue, why a dealership would blatantly lie about this. I am baffled.

I would still like someone to confirm that the dipstick reads 1 quart of oil being burned off. Meaning, if your dipstick shows right at bottom on L, then your car has effectively burned off 1 quart.

Happy thanksgiving everyone!