I know I know this issue has been kicked around a million times but a lot of the threads have gone cold and people will not update. I plan to stay current in this thread as log as others give input. I have the infamous rattle around 1500 to 2000 rpm. I have kept the oil level topped off and changes every 3000 miles. As of lately I have replaced all 3 catalytic converters. The radiator side converter was stopped up with pieces of the honey comb missing. The one between the firewall and engine was stopped up as well. The very rear converter was clear as the new one. I had all heat shields tightened as well as new gaskets. On the way to the shop I was thinking my issue was finally fixed. The mechanic had me get the vehicle up to temperature while holding the brakes and accelerating to the rpm range. He was listening under the hood and said it was coming from the valve train. He explained what was happening was back pressure from the exhaust putting pressure on the valves. I agreed to have all the work done. I picked the car up and after reaching operating temp the noise is still there. I know someone out there with one of these engines has found the culprit for this issue. Anyone with valid input is encouraged to speak up. I know together we can fix this. There are thousands of these Nissans out here needing help. Let's help each other out.

 

Hopefully he didn't charge you alot after not fixing your issue. If it was the valve train what did he do to try to fix the problem. Did he swap the head?

 

No just the converter replacements. No one seems to know exactly what causes this problem.

 

Unfortunately valve adjustments require the shims which don't come cheap. if in fact a valve adjustment is truely needed to fix the rattle....

 

I am far from a mechanic. If that was a definite fix I would pay to stop that noise but throwing money at chance will add up quick

 

No new updates as of yet. I'm just trying to keep it up do date just in case someone else runs into this problem.

 

Bump

 

Timing chain clatter.

Oil leak-down from behind the chain tensioner causing the tensioner piston to not fully and adequately protrude, hence not exert the optimal pressure on the tensioner guide.

Too much slack in the timing chain causing clatter.

 

Or could just be worn chain guides on the primary chain.

OP: Post a good audio recording. That would help more.

 

i have the same rattling sound as well. Tourbo's post above is practically the exact same thing that my mechanic told me.

 

The noise is clearly coming from the top of the motor. I have experienced the timing chain chatter with my Nissan pickup. I am at a loss and don't feel like dropping thousands on guessing. The restricted cats were enough for me for now. It is a great car other than that. May be time to switch to Honda or Toyota.

 

Again, a video would help. I'm not sure what the issue your mechanic is saying about the valves. These cars (as most do now) have hydrolic lifters. Now, if a lifter or more have gone bad and allow space between lifter/rocker or valve/rocker then there will be like a marbles rattling sound. Lifters would be a relatively easy fix.

 

I understand and appreciate your help. I find it hard to believe that as many 3.5 engines out there with this problem no one has had a definite fix. I will try and get a video this week. The noise is very clear on top of the motor around the intake area

 

well op look at the vid and if your lucky this could be the issue. But if is not the case then it's the almighty detonating rattle at part throttle which is bad news for the valves(i would think)and like ACee said not a job for the faint of cash,although i don't think anyone cares to spend that much money on a shot in the dark trying to fix the rattle,the real solution is getting a different car or Better sound system ..

 

Thanks for the video unfortunately it is the dreaded detonating rattle in a specific rpm range.

 

id be interested in this fix as well.... mine does it but its a little tired as i have 210K on it. Im going to do headers and see if that makes it go away. SUPPOSEDLY my heads were redone 70K ago, but the person the car was bought off seemed shady in the least so who knows. figured headers wouldnt be a waste since if I get a new motor than the headers go on... I have noticed that if I run the recommended octane or 93 the knock is gone. Oil also helps mine go away(obviously yours is different)

 

I see why so many of these threads die. Seems no two issues are the same and most people just live with it. It appears I too may as well. Too much money to be spent playing the guessing game