2003 350z
50k miles

When first starting the car in the am, it's fairly quiet. But after it warms up, there seems to be alot of valvetrain noise. It sounds great with the windows closed, but with them open, I can hear the valvetrain noise bouncing off passing cars, and bouncing off the curb beside me. It's fairly loud. But only loud when it gets warm.

Temperature out is around 70+ f

Oil level is good. I'm using 0w30 german castrol which is a thick oil to begin with. Do I try to go thicker? Is it making noise because the oil is thinning? I know 0w40 m1 is slightly thicker them gc

Any suggestions?

 

stay with oem spec....lol

 

10w40 is with oem spec

 

no no no. Motor oil is not a magic potion that fixes stuff. If you have internal motor problems then you have internal motor problems. 5 quarts of oil will not fix it.

 

According to the 2003 owner's manual, 5W30 is the preferred oil for all ambient temperatures.

What makes you think the noise is coming from the valve train?

 

If I had internal motor problems.. wouldn't it show up when engine is cold, or even warming up.

Engine sounds great when cold, and valve train noise starts when it's hot. Which tells me the oil is thinning..

Stethoscope on the heads / valve covers tells me it's valve train noise.

 

There is a procedure in section EM of the service manual for checking the clearance between the lifter and the cam. If it's out of spec, you'll need to get a new lifter with the correct thickness for each out of spec valve. I suspect that could get expensive really fast at $18 each.

Does the noise have a rhythm to it, or is a steady tick, tick, tick. A rhythm would indicate only some valves have too much clearance.

Other than the noise, the excessive valve clearance doesn't hurt much, so I'd be inclined to live with it.

I'm still not completely convinced it's valve related.

 

It doesn't really sound like a tick. It's NOT a knock.

It's sounds more like a clatter. And the clatter isn't coming from the front (so don't think it's timing chain issue). You can't hear it when the windows are closed. You mainly hear it when you are beside a concrete barrier, and the sound bounces back at you, or if there is a car beside you.

I can live with it. It's just annoying sometimes.

I bet buying another set of heads, and installing those the sound would go away. Unless of course those heads have the same issue, lol

It sounds like this: http://youtu.be/MtfFQYgqJag

 

Exhaust leak, gives you a tick when you drive next to a barrier.

 

Sounds just like an exhaust leak driving next to a barrier. But it's not an exhaust leak. Stethoscope says so.

 

look at his other thread... He has a full motor build with a turbo going on.

 

I believe I have the exact same noise. Only hear it when warm.. only hear it when windows down and driving next to car or concert barrier. Hear it more right when I increase revs...

thought it was exhaust related but ran a little bit of seafoam through and didn't see anything leaking. I dont hear it in my engine bay at all... seems like its in the front part of the car underneath?

Let me know if you find anything

 

Try replacing the fuel dampeners.