Clanging Noise From Front of Engine (Probably not Timing Chain)

[Invictus]

Just recently made a trip from South Carolina back here to Atlanta, GA in my '93 240sx (~120k miles). No problems the entire way here, but once I got within the city and slowed down, I could hear an awful noise coming from under the hood that I can best describe as a rock being tossed around in the engine. This afternoon I popped open the hood and tried to figure out where it was coming from, and it sounds like it's directly under the oil cap on the valve cover (sorry, I'm definitely not familiar with auto repair). About 6-7 months ago I had the timing chain components completely replaced, and aside from an overheating problem (that was also repaired), the car has been running fine.

I started the car up and the noise wasn't nearly as loud or as frequent as it was before, but I could still hear an occasionaly clang noise. It doesn't seem to be very rhythmic (it's more random than anything). I remember reading a post that said the fuel injectors will make a clicking sound, but this is definitely a distinctly new noise. I've already had to drop a couple grand into repairs this past year, and I'm dreading the thought that this will involve major engine work again.

Any ideas what could be wrong? I can probably take it back to the mechanic who did the original timing chain work, since it's been less than a year -- but do think it's safe to drive softly for any extended distance?

Thanks for your assistance.

[Invictus]

I just went out to my car again to check the fluid levels, and everything looks fine. Plenty of oil. Starting cold, the sound wasn't very frequent, but as I let the car idle, it got progressively worse. I did notice that every time I start the car, it makes a series of much larger clanging noise, about 3-4 times just after the engine kicks over, then the noise stops for a few seconds, and then grows from being soft to loud and more frequent.

With the hood up, it sounds very much like a piece of plastic flapping around - like putting a card in a rotating fan kind of sound. This was actually my first thought when the sound came up was thinking that the shroud had fallen part of the way off, or there was a large leaf in there, or something, but the fan is clear. The sound is definitely coming from the front of the engine.

Any ideas?

[mygodrulz]

I installed a timing chain set on mine about 6 months ago. When I pulled the rocker cover, I found that the top timing chain guide was missing. All was installed new and it was run for about six months. It developed a noise and when the rocker cover was removed I found that that same guide had broken of and was bouncing around. I'm glad that it didn't drop down into the timing chain area. I wonder if this is a common thing?

[Invictus]

mygodrulz, thanks for your reply. I'm going to have to run it to the mechanic either way because I don't have the knowledge or the comfort level to try to figure this out on my own. Plus, being away at school, I can't really afford to messed it up and be stranded without a car. In a way, it would be great if it turned out to be the timing chain because you can bet I'd be demanding they fix it free of charge.

Any other ideas would be very much appreciated.

[s13sr20chris]

yup, top guide is a common failure item. in fact nissan has a bulletin out to remove it altogether. it is not necessary.

[drftnassmofo]

i just took mine out...it only took like 20 min. or so

[Invictus]

I hope that's all it is. Going to try to take it to the mechanic tomorrow because I don't have the tools or the know-how to start messing around in there.

Thanks for your suggestions fellas.