91 300ZX Noise at Idle

[Z32CheekiBreeki]

So yesterday my Z started making a sorta knocking noise
Sounds like a pulley or a tensioner to me
The noise goes away after driving a for about a minute or when revving/ turning wheel
Was also getting CEL (codes 13 and 34) but those are gone now, corroded connectors I think

[youtube]http://www.youtube.com/watch?v=poe5BQA-4QY[/youtube]

Any help is appreciated, thanks in advance

[Cheeeky Monkey]

pretty sure u have a cracked exhaust manifold. No real test for it but it probably is louder on one side and yes it will get less noisy when it heats up. Stock manifolds? Oh darn looks like you might have to put a set of headers on it. I however had to weld mine up three time on a Infinity J30 (same Motor less hp)
Tom

[Z32CheekiBreeki]

stock manifolds, however when I listen to it more carefully it does appear to be louder on the driver side, how ever it sounds like it is coming from the top end.
oil pressure looks off, though im fairly sure the sender unit/gauge is gone
could it be lifter tick? or belt noise?

[Cheeeky Monkey]

It will sound like it is coming from hi on the motor. The noise that you had in your vid was way to loud for a lifter tick. and no bearing will make a noise like that. I did remember that you will be able to see a different color spot on the heat shield that covers the manifold. The manifolds will crack In the corners where the primary's join each other. BTW it will be very difficult to see the different color spot. If it is any consult my z32 has manifolds that are cracked. I don't know if the heat shield causes the problem or the way the manifold is built but it seems they all crack after 100,000 miles.

[Z32CheekiBreeki]

UPDATE

took it to a mechanic and he determined it was a bad lifter
he is telling me it'll be about ~$2000-2500 to fix (also have a leaky power steering pump to replace)
does that seem right?

[nissanfreak12]

Before spending all that money on a mechanic, google lifter tick on the 300zx. You will get a lot of people that have fixed that issue. Ours are Hydraulic, when they make a lot of noise, usually means they are not getting oil in them, as they collapse.

I used ATF mixed with oil, probably about 1/2 quart, ran it for 200-300 miles, not hard, cleared it right up. Engine is quiet and smooth.

Z1 makes an engine cleaner people has had luck with, marvel mystery oil, seafoam. Just search and do what you think with work for you.

[Z-owned]

really doesn't sound like lifter tick but video's are always hard to tell. Typically though with a lifter you should hear the ticking get faster as the rpm's increase. I would try the ATF like said or marvel mystery oil which I have used with success before paying someone.

[Z32CheekiBreeki]

Typically though with a lifter you should hear the ticking get faster as the rpm's increase.

thats what i was under the impression of aswell
the noise goes away after driving for not even a minute
also does not come right away when idling

mechanic said that the lifters might just not be getting enough oil at idle
oil pressure reads normal though

the guy was a datsun/nissan master tech but still gonna get a second opinion

[nissanfreak12]

I just listen to the video, i have to agree with Cheeky, it sounds like a cracked manifold or gasket gave out. Definitely doesn't sound like lifters, like zowned said, they would speed up.

[Z32CheekiBreeki]

definitely not a cracked exhaust gasket or manifold. went through with a stethoscope and the noise is coming from behind the drivers side cam gears on the drivers side
VTC spring is good so not that

also, found out that the drivers side VTC solenoid isnt functioning properly (power going in but not back out)
looking more closely into the noise, I've noticed that it only comes at ~1000 rpm, which explains why the noise isnt there when cold, but as it gradually starts to
warm up the noise would come and go away once its fully warmed up (~700-800 rpm)
the noise has also sort of begun to subside (definitely alot quieter now and does not come as frequently)

since both the noise and solenoid problem is on the drivers side, could the two be related?
im going to try and replace the solenoid regardless
any advice on the job? level of difficulty? location of the solenoid?


thanks again for the replies btw