99 Chevy Cavalier Z24 (2.4l)

When I accelerate (most noticiably when I hit 2000+ RPMs) I here a ticking noise coming from under the hood. The noise gets louder in direct proportion to acceleration. It's not quite a "knocking" noise, but is audible from inside the car with the music off. It's very faint, but present, when the car is in idle also. I'm hoping its not a thrown rod as i can afford a rebuild or new engine. i know it could be many things, but I was wondering if anyone knew what it could be, or where the best/cheapest place to take it to get a diagnosis. Any help would be greatly appreciated.

5/24/2010 2:47:17 PM

Is your oil topped off?

5/24/2010 2:55:40 PM

It's not a thrown rod.

Could be a valve ticking. A lot of cars do that for hundreds of thousands of miles with no problem. You could try running one of those oil detergents in there and changing the oil to clear up any blocked oil passages.

Could be a misfire caused by a bad spark plug wire, plug, etc.
Could be a lot of things I guess.

5/24/2010 2:57:34 PM

exhaust leak?

[Edited on May 24, 2010 at 3:08 PM. Reason : check your oil level first]

5/24/2010 3:07:52 PM

oil was about half a quart low...topped it off and ran it about an hour total over the weekend...noise didn't get any better. i might try a can of Seafoam...i didnt see any immediate gunk when i removed the oil cap and looked down though. Spark plug wires should be fine, they were replaced along with the alternator about 20,000 miles ago but i might check the actual plugs and replace them just for kicks, they are cheap. What do you guys think about a rod bearing? Im hoping not!

5/24/2010 4:18:09 PM

something in the belt assembly

5/24/2010 4:20:32 PM

lifter tick or exhaust leak are the usual culprits. Dump a quart of engine flush in there, get it hot, then change the oil.

[Edited on May 24, 2010 at 4:42 PM. Reason : Take the belts off to eliminate pulley bearings as a source of the tick.]

5/24/2010 4:42:04 PM

Thanks guys! ill look into all the suggestions and let ya know how things go...for now im gonna get some cleaner and run it through the oil...then get it changed and post back here.

5/24/2010 5:56:41 PM

could be a little bit of knock

see if it goes away with higher octane

5/24/2010 6:16:50 PM

^ Yeah, if it's random (i.e. not perfectly timed and going up and down as the engine RPMs increase or decrease) it could just be detonation which would likely go away with higher octane fuel. If that's the case it's probably worth finding the cause and nipping it in the bud rather than just running better gas for the rest of the life of the vehicle.

[Edited on May 24, 2010 at 6:19 PM. Reason : l]

5/24/2010 6:18:59 PM

what would that be? vac line for the retard fell off? distributor a little on the advance side?

5/24/2010 6:20:35 PM

I think carbon buildup on the piston is the most common cause. It creates a hot spot that burns the fuel before the spark plug actually fires and thus detonation. Sea Foam will usually do the trick.

5/24/2010 6:26:55 PM

bet it needs new sparkplugs and wires

[Edited on May 24, 2010 at 7:38 PM. Reason : .]

5/24/2010 7:37:30 PM

I'll bet a dozen Krispy Kremes it's an exhaust leak.

5/25/2010 7:40:33 AM

^^

The guy knows what rod knock and sea foam are. I'm pretty sure he knows what a misfire feels like, lol.

5/25/2010 7:57:03 AM

whatever it is, I think it might pose a danger to manifold

5/25/2010 9:10:56 AM