My 97 plymouth neon, dohc auto. Has a slight knocking noise when you first start it up in the mornings. Worse in the winter when it's cold, but once it gets up to operationg temp, it virtually goes away. It's got 110k on it, and I've driven the **** out of it for the last 3 months with it making this noise and it hasn't come apart yet, so I'm pretty much saying it's not a spun bearing or something. Just wondering what it could be. When I got it the timing belt was broken, so I replaced that, the water pump, 2 exhaust valves, and worked the head over. It's done great and got 38 mpg on it's last road trip... I've been told possibly wore cylinders/pistons maybe causing a little piston slap? Doesn't seem major but I'm still curious if anyone elses car does the same thing, or if maybe it's just a neon thing, similar to their rough idle at times?

 

I've had more than a few cars that knocked when they were cold, sometimes putting in a different weight oil helped. If it goes away after it warms up, I wouldn't worry all that much about it unless it gets worse....

Dusty

 

Probably piston slap...normal on neons and nothing to worry about. Just keep an eye on it.

 

sounds like early detonation. wat kinda plugs do you have in there? do you no where the knockin comes from? the top? I heard that if your plug burns to hot it'll cause early detonation or sumn. if you have platinums or 4+ or watever that could b it. just a guess tho.
Piston slap is normal for the neon? that doesnt sound healthy...I ain a Neon expert, but I do no that detonation is never a good thing =)

 

If it's detonating it would sound almost like a rattle in a spray can while your driving the engine under load.

And yes piston slap is common the neon because of the skirts, but takes a long time to show any ill effects.

 

About what I figured, thanks for the replys. Running regular autolite plugs, no platinum bull or multiple ground crap. Sounds like just a typical neon annoyance that I'm just going to have to deal with. Thanks guys!

 

hey there...just gotta chime in...had the exact same problem in my 99 dohc r/t ....rode that sucker hard and it still ran awsome.....until friday night when it finally finished spinning the bearing. so if i were you...i would take the hour or so and drop the pan to check for loose caps....worst case you get to change your oil and if your vareful you can reuse the gasket. Good luck