Odd Clacking Noise When Hot

[rico05]

So I have heard this odd clacking noise when the motor is hot. It does not increase in frequency or volume as I rev the engine under load, so I was thinking something was loose. It does not do it all the time is the odd thing. Yesterday, however, on the drive home from work I heard it, so I pulled over to investigate. Previously, I have never been able to make the noise happen at idle, but yesterday I did. I found that I could make the noise happen only as I quickly openen the throttle by hand. Like, if I gradually revved the engine, nothing. But if I quickly opened the throttle, then let off, it would happen. It seems to be coming from the front cover or intake cam area. It has me stumped. It does not sound like rod knock. The closest thing I can compare it to is the noise my timing chain made when I blew up the tensioner on my old KA, but MUCH quieter. I got pissed, and let the car sit. I came back to it after dinner (cold engine) and the noise was gone. WTF?

I just changed oil and plugs. The only thing I have really done is change from my previous open upper timing cover to a stock closed one, resetting my timing chain tension in the process. Other than that, I am stumped. Any ideas? My gut reaction is collapsed lifter.

[boost_boy]

Make sure that you have all of the screws in the upper timing cover and being wary of crank angle sensor. If the cover is out of alignment or tightened at all corners, you will hear strange noises. I've heard them before, but I didn't care because I don't have a crank angle sensor. But in your case, be wary cover for the crank angle sensor's sake.

Dee

[rico05]

Will do. I just swapped in my new battery (upgraded from Optima Red Top to a Yellow Top. WOOT!), and I ran the car to check the charging system and no noise. Damn if it does not have me stumped.

[Katapl]

Rico, my timing cover is just like your older one and I'm hearing the exact same noise. My timing cover is still fastened really well. At first, I thought it was a lifter. Are you sure it's not possibly the waterpump? My old man thinks thats most likely what it is. He's told me he heard that sound quite a few times before his went bad.

I'm probably replacing mine next week for reassurance, at least.

p.s. I think the noise has been there even before I changed out my cover. Like I said, I always thought it was a lifter, but it's been getting considerably louder. Not much, but still enough to hear it with the hood open. Mine also sounds to be coming from the front of the engine somewhere.

[rico05]

I was thinking water pump as well...I hope not. I don't want to have to pull the crank pulley. Good thing the part is like $15 at work.

[dattodude]

I'm thinking it's timing belt tensioner bearings.

They can sound like crap after 20 years.