Engine Knock!!

[M35SFIREMEDIC]

Hey guys, I'm trying to help out a friend. She has a 2010 G37 and when she starts the engine she hears a loud noise and then she hears a low engine knock. The dealership says it might be a pully but it sounds like a possible oil pimp. The noise started after oil change. I also posted this on the G37 engine forum. Any suggestions? Thanks for replies.

[GenericM35]

Hey guys, I'm trying to help out a friend. She has a 2010 G37 and when she starts the engine she hears a loud noise and then she hears a low engine knock. The dealership says it might be a pully but it sounds like a possible oil pimp. The noise started after oil change. I also posted this on the G37 engine forum. Any suggestions? Thanks for replies.

I don't have the loud sound at startup, but I definitely have that low engine knock sound you're referring to. Several members here have it, actually. It seems to be a normal issue with this engine, and I don't think it'll cause any problems in the future if the sound doesn't bother her too much.

[antzrus]

Hey guys, I'm trying to help out a friend. She has a 2010 G37 and when she starts the engine she hears a loud noise and then she hears a low engine knock. The dealership says it might be a pully but it sounds like a possible oil pimp. The noise started after oil change. I also posted this on the G37 engine forum. Any suggestions? Thanks for replies.

She ought not to be hangin' with pimps in the first place...

[M35SFIREMEDIC]

WOW !!!! Let me see if I understand. Several members have had this problem, and no one has come up with a solution?? I assume that my friend will let the stealership replace whatever they think the problem is since the car is still under warranty, but I don't except the answer that this is an issue that infiniti car owners will just have to get use too. .This sounds like some carmax BS, I had a brake issue with a car I purchased from carmax and they told me I would have to just deal with the scrubbing sound coming from the brakes because the car was still stopping. Needless to say I went ape$#!+ on them and they had to refund my money. Please understand I'm not coming down on you( GenericM35) because I hate smart a** replies, I'm just trying to help a friend because I've been taken by the stealership before myself. Thanks for reply.

[M35SFIREMEDIC]

@ Antzrus, oops type O.

[antzrus]

@ Antzrus, oops type O.

Oh, never mind...

[wingFeather]

It is hard to diagnose from the description. Does her engine sound like your on startup? They are both VQ blocks & should sound somewhat similar.

[CPJ LB]

Hey guys, I'm trying to help out a friend. She has a 2010 G37 and when she starts the engine she hears a loud noise and then she hears a low engine knock. The dealership says it might be a pully but it sounds like a possible oil pimp. The noise started after oil change. I also posted this on the G37 engine forum. Any suggestions? Thanks for replies.

where is her oil level -- after the oil change and hearing the noise?? does the noise continue??? does the engine run hot??? it would suck to be the oil pump on a relatively 'new' car... maybe post a video??

sorry, I wish I had some answers....

[M35SFIREMEDIC]

I work with the guy she is dating and I let him hear my engine at start up and he said her engine is a lot louder than mine, and we didn't hear any knocking.Not sure about oil level, but the oil had just been changed. The dealer has the car now and she is in a loaner. I will post the solution if they find one . Thanks for all replies.

[zerg711]

Unless the owner has a ton of miles on the car, I don't understand why you are asking question on the boards when you should take the car in to the dealer and have them fix it under warranty. It is a 2010 right?

[The00Dustin]

Unless the owner has a ton of miles on the car, I don't understand why you are asking question on the boards when you should take the car in to the dealer and have them fix it under warranty. It is a 2010 right?

It's nice to know what's wrong with your car, and not all dealers are honest. Besides, by starting a discussion here, forum members can hope for an update once the dealer fixes it under warranty, and then we have another problem and fix documented for the future when some other vehicle isn't under warranty.

[GenericM35]

WOW !!!! Let me see if I understand. Several members have had this problem, and no one has come up with a solution?? I assume that my friend will let the stealership replace whatever they think the problem is since the car is still under warranty, but I don't except the answer that this is an issue that infiniti car owners will just have to get use too. .This sounds like some carmax BS, I had a brake issue with a car I purchased from carmax and they told me I would have to just deal with the scrubbing sound coming from the brakes because the car was still stopping. Needless to say I went ape$#!+ on them and they had to refund my money. Please understand I'm not coming down on you( GenericM35) because I hate smart a** replies, I'm just trying to help a friend because I've been taken by the stealership before myself. Thanks for reply.

No offense at all. I'd love to see this issue resolved as well.

Not sure if this helps, but I and several other members with the sound all had the same symptoms:
- The sound is heard only at idle when the engine is warm, and the car is in Park/Neutral
- Putting the car in Drive/Reverse, or turning on the AC eliminates the sound

If you are able to learn anything about this mysterious sound, please let us know!

[GenericM35]

I was searching for similar sounds online, and found this. It is pretty much exactly how I would describe the sound (minus the oil cap and the transmission slipping) on a BMW 5

E60 Rattle at idle
"I just changed the oil seperator, hoses and repaired the disa valve, runs much better and no more smoking!! The problem is at Idle warm or cold the engine has a rattle that is very hard to tell where it is coming from. It sounds like it is coming from the intake area but you can hear it near the front of the engine as well as the right side. When the A/C is on the noise seems to fade, also if i bring the idle up about 100 rpm the noise goes away. I found something weird, when I unscrew the oil cap while running, the noise goes away??? Put the cap on and in about 10 seconds the noise gradually gets louder until full volume. Fresh oil, no change, new disa and oil sep valves, no change??? also 3-4 shift seems to be jumping like the trans is hunting for a gear, but when floored in 3rd, no slip..."
http://forums.bimmerforums.com/forum/sh ... ?t=1898260

P.S. Just looking at that forum makes me glad I choose the M over the 5 Series, which was my other option at the time

[DJPlayedYA]

Diagnosing engine knocks without even seeing and hearing the vehicle is like throwing darts in the dark. It could be a number of things...rods, lifters, valves, pulleys, tensioners...and the list goes on. If it just happened after an oil change, and the car was perfect before she took it there, then it is most likely something simple. However, since it is under warranty, why sweat about it? She's getting free OEM parts

[M35SFIREMEDIC]

Talked to my friend and he said the dealership said the problem was the fuel dampener. However the noise is still there. I'll try to get them to post the sound. Thanks for the posts.

[White-Rush]

While my car is only a 2006, I recently test drove a 2011 M37S and experienced something similar to this, on 3 separate test drives. This car was used, with just over 30k miles on it and upon startup, it sounded terrible. That was the only M37 that i have any experience with, but I can't imagine that sound being normal. After we backed out and got out on the streets, the car drove very good and didnt' give off any "odd" sound what-so-ever.

It could be possible that this is a recurring problem in that engine, upon startup or at idle. I would love to get more information on this because I'm pretty sure that i'll be purchasing an M37 within the next few months.

[M35SFIREMEDIC]

@ White-rush, I drove the new M37s as well I'm also thinking about an upgrade, maybe in about a year very nice car, roomy yet powerful. Only thing better would be the M56s. I looking for a pre-owned '11 or 12 in either model which ever is the best deal for the money. Good luck with your future purchase.

[White-Rush]

Yes, it's a very nice car. Had the one that I test drove, not sounded so bad at startup - I would have made the purchase already. But as you said, i'm really hoping to find a good deal on a pre-owned 56S...

[jjcuff1]

Not sure if I am missing something here. But these engines are Direct Injection. All DI engines battle the sound issue. Look at the Cadillac CTS, they have the worse NVH at idle in IMHO. I assume you are hearing this. I reduce emissions at idle (when they are the highest) and reduce gas consumption they do run leaner. Unlike Fuel Injection that uses the the valves and intake manifold to inject fuel the DI engines have more flexibility to control the fuel air ratio. and in essence overlap the intake/exhaust openings independent of the fuel injection to maximize their AFR, Emissions, Gas consumption. So At idle on the DI engines which are similar more to A diesel cycle the loudness you hear is similar to knocking/detonation in a Fuel Injected engine but in essence it is really Cavitation and you are hearing back pressure and different acoustics that may not come through the intake or the exhaust in a FI engine but can be reverberating into the intake or exhaust differently to maintain higher c/r or different AFR ratios.

[GenericM35]

YES! Update on my situation (that will hopefully help others): I just had the accessory belt replaced today as recommended by Infiniti, and it worked! No more knocking sound at idle!

[M35SFIREMEDIC]

@ jjcuff1 your post makes since, if it was explained that way at the dealership I think my buddy and his girl would have understood. Thanks for the post.

[M35SFIREMEDIC]

@ generic M35 thanks also I will pass on the info. you guys have been very helpful!!!