Nissan Altima 3.5 2008....knocking noise when cold

[Spartan07]

Hey fellas.
My damn car is acting up. When I crank it in the morning it cranks fine, when I pull out of the driveway before it warms up and go up to at least 2000 rpm to get it on the road...it has this knocking sound coming from the engine. The sound goes away when it has warmed up, and the motor runs fine. I just can't help but think that this is screwing up my motor...
I'm going to try to run some higher octane and see if it helps...
Any nissan mechanics on here???

 

[Lazarus]

You check your oil level? The VQs are notorious for burning oil and the valves start clacking.

 

[Constitution Hour]

It is the clutch on your camshaft making noise. Nissan uses Variable Valve timing to change cam timing, the springs get worn and they start to make a loud knocking noise. Oil changes are VERY important on these cars.
There is also a screen in the oil passage for the solenoid for the cam timing, that screen can get restricted with gunk causing low oil pressure to the cam clutch mechanism causing the kncoking noise. You need to get it checked and or fixwd before it causes more damage.

 

[Constitution Hour]

[h=2]NTB07021[/h]

• IF YOU CONFIRM When the engine is started after a "cold soak" of more than 4 hours: - There is a rattle for 1-2 seconds (if the rattle noise lasts longer than 2 seconds this bulletin does not apply), and - the rattle noise is not coming from the catalytic converter heat shield (see campaign bulletin NTB08-001), and - the rattle is coming from the IVT (Intake Valve Timing) sprocket / camshaft intake sprocket at the front of the engine, and - the engine oil level is confirmed to be in the"operating" range. ACTION Refer to the Repair Flow Chart on page 2 of this bulletin to determine the correct actions for the vehicle you are working on. See this bulletin for further detail.

 

[Spartan07]

Not sure what flow chart you're referring to. I believe that it is coming from the engine, not the cat. Engine oil level is in the operating range.
I'll take it in this week.

 

[Constitution Hour]

The flow chart is in the Nissan factory Manual. Yes I know the noise is not coming from thwe Cat, (see underlined segment) as I said it is coming from the Intake cam shaft Variable Valve timing sprocket.
Since it happens cold and goes away I would suggest cleaning the screen for the vvt solenoid. Here is more on the topic from the Nissan TSB database. " Do Not replace the variable valve timing Solenoid Valve or the Sprocket(s) without performing the complete diagnostics indicated in the EC section of the Service Manual. The first step in the complete diagnostic is to make sure the engine oil is at the operating level and oil pressure is normal when measured with a gauge at the pressure switch port. See this bulletin for further detail."
Sorry i do not have the factory manual. I am trying to locate the information for you.

 

[Constitution Hour]

here is a good article. However notice they are talking about a "ticking or tapping noise . You said it is a Knocking noise. In my 30 plus years of working on cars, when I have encountered the noise you describe on a late model Nissan V6 it has been the cam sprocket or a restricted oil passage to said sprocket. Many of these engines use a screen in the passage way to catch debris before it reaches the solenoid that control the flow of oil to the sprocket. When the screen is partially restricted cold oil (thicker) will not pass through, as the oil heats up it can more easily pass through the restricted screen.
I am on Vacation this week so I do not have any technical data available such as Aldata or Mitchell. I do not recall if and where the screen may be located on your Nissan, they will usually have an access plug that can be removed to clean the passage. (it will be close to or near the solenoid) usually on the side of the cylinder head or engine block.

 

[Constitution Hour]

http://www.denlorstools.com/autoblog/2009/09/3-5-nissan-engine-noise-tapping-at-cold-start-up/