Engine Noise, 1990 240SX

[Warped]

So i'm getting ready to go out last night and i hear an odd noise from under the hood as i am walking past my car.(it's already running), so i pop the hood and there is an odd rattle that seems to be coming from the valve cover. when i tap the throttle it goes away but it comes back as soon as the engine revs back down. the car has oil in it and it doesn't need to be changed. could it just be the the guides on the timing chain or could it be possible valve problems..1990 240sx with 175,000 miles. HELP,thanks in advance. if i can i will record the sound tommorow and post it.

[SidewaysGts]

Pull the valve covers off and take a look- shouldnt be that hard to remove.

[Whisky]

Had exactly the same problem on my cousin's S13 (1990 with 230,000 on the clock). Sounded like it was coming from under the valve cover, but if you tapped the gas it would go away. Turned out to be the heat shield on the exhaust manifold. Removed the shield and the noise is long gone. I would do that before you pull the valve cover off.

[Warped]

i have already removed the heat shield from the exhaust manifold, unless it's the rest of the shielding that continues down the pipe. and actually the valve cover is a pain in the *Censored**Censored**Censored* to remove, the valves fit so snug inside it that it's real annoying to try and just pull the cover.

[raging panda]

could be timing chain rattle

[Warped]

yeah i thougt of that, you can hear the timing chain rattle for about 10 seconds when i first start up, then the tensioner kicks in. i'm really hoping it's just the heat sheilds on the lower half of the exhaust, won't know till the weather gets a little warmer- it's about 3 degree's outside right now.

[dancinghobo]

do you have any coolant? oil? it could be your timing chain but i wouldnt buy a timing chain kit unless i was certain.

[Warped]

yes all the fluids are topped off, it was the first thing i checked, but when your outside the car with the hood closed you can hear the noise as if it is coming from under the car. i reallly don't wan't to have to change my timing belt.

[dancinghobo]

how loud is it? have you driven it?

[Warped]

i really don't hear it when i;m driving, i noticed it when the car was running and i was outside the car. like i said you really only hear it when the throttle is coming down and the exhaust is to loud to hear it when i'm driving.

[C2POWERHAUS (H)]

It's most likely the timing chain...my friend has had the same problem for the last year. As it gets worse, its just gonna get louder and louder, especially on start up. You have to take off valve cover and and feel how loose the chain is...only way of knowing for sure. It also would be a good idea to change it anyway if your motor has a lot of miles too.

[Warped]

i thought of changing the chain before, it's a big job and not cheap at all if you have a mechanic do it.

[C2POWERHAUS (H)]

True true...the chain itself is actually quite pricey unless you have connections or something...if you want to avoid mechanic costs, you could always do it yourself