Engine knocking at idle

[Gumbie]

I recently purchased a 2005 G35 Sedan with 64k miles on it for my wife as a daily driver. We've had the car for a month and everything has been good so far. Last night while the car was idling I noticed a knocking sound coming from the engine. After looking around online I found this video on youtube

http://www.youtube.com/watch?v=Hk5A6MFla4Y

The sound mine is making has the same tone and frequency as the youtube video but it's not that loud (yet). The only thing that's changed with the car since we bought it is having the oil changed last week (Castrol GTX 5w30) and the current tank of gas has a bottle of Lucas fuel treatment in it. I really appreciate any advice anyone can offer. Thanks

[G_whizz]

Welcome to NICO and sorry to hear of your troubles.

To my knowledge...our cars HATE any fuel additives. What grade of fuel does your manuel say to use? 87 or 91.

If your gas is VERY low, I recommend filling it with 91 to see if that makes any difference.

Did you not hear this knocking when you test drove the car? Will the stealership help you out at all? Was there any warranty left?

If you take it back I would definitley omit the fact that you added a fuel additive.

Hopefully this helps you as well..

http://www2.zhome.com:81/ZCMnL....html

[Gumbie]

Thanks for the response. The manual states I can run 87 in it, but I think I'll put some 93 in it later today to see if it helps. The sound wasn't there when the car was bought, plus I even had a reputable independent mechanic shop look the car over when it was first bought and no problems were found. The sound wasn't there till after the oil change and the fuel treatment, but since they were both done so close together I'm not sure which one caused it. Unfortunately in Tennessee there's no used car lemon law so the dealership is off scotch free. I do still have the Infiniti drivetrain warranty, but since I bought the car used I have no record of any routine maintenance...therefore they won't touch it.

[Poyzinous]

There are a couple of fuel additives you can use on VQ motors. Anything BG is fine. I actually use a can of BG fuel additive once a month. Castrol GTX is conventional oil isn't it? Try using a sythetic blend or full synthetic. But not Castrol. Quaker state or mobil 1. And My G35 can run on regular but I despise engine knock and I have 2* timing advance(thanks steve) and I like progressive combustion out of my VVT so I use Premium since in Northern VA its 93 and I can find it at about $2.15^9/10 per gal.

[G_whizz]

Yeah I figured it was 87.

Try min.91 to see if that makes a difference. Could be an oil pressure problem...is there any lights on?

Heres a good read as well

http://www.autohausaz.com/html/oil_pressure.html

If it was only a month ago...I would at least try and call the stealership that sold it to you and see if they'll do anything to help you. Hell...it's worth a try.

Good luck and let us know what happens!!

[G_whizz]

There are a couple of fuel additives you can use on VQ motors. Anything BG is fine. I actually use a can of BG fuel additive once a month. Castrol GTX is conventional oil isn't it? Try using a sythetic blend or full synthetic. But not Castrol. Quaker state or mobil 1. And My G35 can run on regular but I despise engine knock and I have 2* timing advance(thanks steve) and I like progressive combustion out of my VVT so I use Premium since in Northern VA its 93 and I can find it at about $2.15^9/10 per gal.

Really?? I was told the VQ's don't agree with ANY additives..oil or fuel.

But, since you're the Infiniti tech...I'll take your word for it.

Definitley the synthetic is the way to go. ALOT of guys here go with Royal Purple.

[Poyzinous]

Stealership? Come on Sean. Thats mean. what am I? a Stealership Empolythief? A Stealership Representathief? I dont lie to my customers. I can't lie. I'll get a facial erect!on.

[G_whizz]

LOL..I was referring to the private dealership where the OP bought his car..

[tollboothwilley]

I use Lucas fuel treatment regularly in my car. No problems at all. Its not the Lucas.

It could be the regular (87) gas but I think you need to check the more serious possibility of oil consumption. Someone just had this exact thing happen (i can't remember the SN of that person). Turned out they were like 3 quarts low Getting a new engine though, under warranty.

Some people have had issues with other changing their oil too. Be careful with you let handle your "business".

[pfarmer]

I recently purchased a 2005 G35 Sedan with 64k miles on it for my wife as a daily driver. We've had the car for a month and everything has been good so far. Last night while the car was idling I noticed a knocking sound coming from the engine. After looking around online I found this video on youtube

http://www.youtube.com/watch?v=Hk5A6MFla4Y

The sound mine is making has the same tone and frequency as the youtube video but it's not that loud (yet). The only thing that's changed with the car since we bought it is having the oil changed last week (Castrol GTX 5w30) and the current tank of gas has a bottle of Lucas fuel treatment in it. I really appreciate any advice anyone can offer. Thanks

I would not use the fuel treatment. The oil may or may not be ok for your engine, you may want to make another change and have this one done using something else, possibly even from Infiniti.

However are you sure it is the engine and not something like an accessory such as air conditioning or a pulley driving one of these? For air conditioning you can simply turn it on and off (entirely off not simply another mode). Look at belt deflection when the noise is present and when it is not. While deflection may change with rpm due to loading does it also change as far as running straight and true?

Perry

[uprev]

Any updates?

[darrell b]

Our 2009 g37 started knocking at 3000 kms. It mostly happened in hot weather when just idling or putting around. Although they tried several things to take care of the problem nothing worked and we got angry and frustrated with all the trips to the dealer. Took them 50000 kms to figure out that a gasket inside the timing chain cover fails causing intermittent low oil pressure resulting in knocking sound. Took them a month to repair it at Dilawri Infiniti Nissan Regina, Sk. We have since put 40000 kms on it with no further noise but recently we have noticed a similar noise again.
We have no confidence in our engine not failing us after having low oil pressure. They refused to replace the engine. They would only replace the timing parts and cover even though we believe the low oil psi would have damaged every moving part in the engine. The mechanic wanted put anew long block in, even stating it would have been less work but infiniti tech would not let them. I will never buy any nissan product again.