Hey there, I am not sure, I was reading around and recognized some of my symptoms
When I start my car in the morning, it knocks for about 3-5 seconds (very noticable, but doesn't sounds like its about to blow up)

When I am driving, every now and then I hear a knocking noise continuously for maybe 10 seconds, then I notice it and drop rpms, normally after the car has been warming up, in the operating temp range, but its cold outside, I am in second accelerating

It has been doing this for months, do you think it could be a mild spin?
and cheap fixes?
I am running 10w40...maybe 30, I am in CO and its been cold lately

 

all the spun bearings that iv had to deal with made knocking noise all the time.. regardless of weather... its new motor time for u..

 

are u sure its not timimg chain noise...might time for Tensioners and guides

 

it's not a spun bearing, yet, but it could be bearing noise. it could also be piston slap, the TC tensioner, or even the AC compressor.

some things you can do -- experiment with different oils. don't use 10W40 -- use a good 5W30 or 0W30. I had cold start knock that went away when I put in valvoline maxlife synthetic 5W30.

also, put on a 37" alternator belt (to bypass the AC compressor) and see if that gets rid of the noise. AC compressors have pistons & a swash plate that can knock just like rod bearings. even if the AC is off, the pulley could be making noise (bad pulley bearing).

take an audio/video clip from under the car at cold start and post it online so we can hear the noise.

 

Hey there, I will definately try some of those experiments
thanks for the ideas

 

I'm 99.9% sure that's not the case. The super-tight piston-to-wall clearance and wrist pin offset guarantee quiet piston operation.

 

cylinders wear out with time, neglect, & abuse. not the most likely cause I'll grant you that, but even the FSM lists piston slap as a potential source of noise..

 

oooooooooooooohhhhhhhhhhhhh snap!!!!!

 

I'm familiar with that part of the FSM and have seen it before. That's just a generic guide telling you were noises can come from in broad, general terms. I'm just telling you, from my experience and for all practical purposes, piston slap is non-existant on these motors, neglect/abuse or not. I abused the VQ that had 140k+ w/multiple oil leaks on my last maxima (running it to redline many many many many times with 2 quarts of oil or less) and there was never an indication of piston slap. Not even a spun bearing. I stick by what i said before. The tight clearance and wrist pin offset ensure no slap. Not to mention the high rod-to-stroke ratio that minimizes thrust loads on the cylinder wall. Also, if the cylinder wall has worn enough to allow for piston slap there will be higher-than-normal oil consumption. Don't hear of that too often with the VQ30.

 

Anything else?

 

hey nismo - I wasn't tyring to pick on you. sorry if it came across that way. you're one of the more knowledgeable people on here and I enjoy reading your posts. you certainly are correct that lower-end failures are not common to the VQ. I was just trying to give the poor guy all his options.

I don't know what "oh snap!" means -- was that a dig on you or me?

 

no nothing just wanted to see what ur reaction was gonna be....

 

I'm curious. Sometimes when I don't drive the car for a couple days, then when I start it up, there'll be a brief knocking noise before pressure builds up. Is that pistons, valves or lifter noise?

 

If it was piston slap it wouldn't go away after just a few seconds. It might be the timing chain tensioner or valvetrain noise.

 

huh, heated debate...at any rate I hate working on damn cars. I am nearing the end of oa multi month rock crawler build: 83 toyota, rebuilt 22r mild cam etc, full width gm axles, 3/4 elliptical leaf sprung set up, hydraulic steering, dual transfer cases, tranny swap, tubed bed, full cage, narrowed ft end....etc....etc....on and on and I am sick of being in the garage and spending money on little $40 purchases multiple times everyday.

Venting is over, I just don't wanna work on anything, but I gues I better address the issue

Thanks again for the input

 

Timing chain tensioner son, my beater 95 max with 200k miles on it makes the exact same noises under the same circumstances.

 

I'm not trying to steal the OP's thread, nor am I trying to debate anything, just want to know....
but if it were the tensioner, wouldn't the noise continue instead of stopping? This only happens (when it does) if the car has not been driven in a couple days. The noise may last for two seconds then it's gone....

 

Hey Neal, an '05 TL is still faster than a 5.5 Gen.. j/k

 

Hey it's all good. You certainly know your stuff as well. Sorry if i sounded argumentative.