Knock....

[TjXiong]

I have been posting this a few time but I still don't have clue to what that has been causing the knock. When the engine is dead cold and I start up the engine there will be a knock the knocks. It does not sound like a tick. As I rev up the engine the knock knocks faster as I rev the engine into higher rpm. Once the car is being driven for a while the knocks seems to go away. But a little after the knock seems to come back. I'm not sure if its the rod/piston. 99 gs 420a motor. Any clue.... The motor is all stock. No mods. I havent take the oil pan off yet to see if there is anything.

[munchgsx]

Sounds like a crank bearing.

[TsiTom]

Is it an auto or 5 speed?

[TjXiong]

It is a 5 speed.

[TsiTom]

Could be piston slap too...that would be heard at startup and diminish as the car warms up...

[TjXiong]

Yeah, some of my buddies say so to but I just wanted to know if the knocking will cause any future problem that I just want to avoid. It seems to be like this for 1 year plus now and doesn't seem to be cause any trouble beside knocking.

[iceminion]

My guess rod bearings.

Inspect the oil for metal shavings.

You can take the oil pan off and physically wiggle the rod caps, they should all be tight with about a milimeter of play side to side, or less. if one is totally out of wack then you need to do a rebuild.

You could try to replace just the rod bearings, you can do that in some cars without pulling the engine, my buddy just did his rod bearings in his VW with ease and it fixed his "clunking" problem....I say clunking because "knock" means something totally different on this forum.

The Neon motor is known for its piston slap, its a POS.

If your bearings are going bad then you should try to fix it as soon as possible.

I hear that you can build up a 420a and make some nice power with forged internals :)

[TjXiong]

Yeah I'll have to wait for the spring to be able to do that. Its too cold unless if I take it to the shop.

[Halon]

My car does this somewhat upon initial startup, but after a couple minutes of warming up it's gone. Pretty sure mine is piston slap though as I have forged internals. Except it is more of a ticking sound than a loud knocking.

[TjXiong]

I'm not so sure to what it is. I drive it around town and park the car with the engine on and once I sometime rev the engine the knocks seems to come back again.