2009 Kia Rio4 dr Sedan LX Manual Transmisson
Thanks, I'd appreciate any ideas you might have. The noise isn't just annoying, but could be a sign that something is wrong that could cause more serious problems down the line.
Also, although I doubt it's related, the car also sometimes idles somewhat roughly. What happens is that I'm stopped at a light, foot on brake, and every now and then engine power dips down for a split second, then goes back to normal, then again. I recently replaced the plugs, PCV, purge valve and air filter (also cleaned the filter box), did an oil and filter change, and cleaned the throttle and idle control valve.
I also put some Techron in the fuel. There don't appear to be any air leaks. I'm guessing that it's either the fuel injectors or fuel pump or filter, and unrelated to the howling/rattling noise, but I mentioned it here in case it might be related. There are no other major problems with the car, just the usual minor or secondary jobs that need to be done (dead radio, body dings, chipped paint, needs new bushings and shocks, etc.)
Also, in response to your other comment, I'll try this, but the car doesn't have a timing chain, rather a belt. There is a chain, but it connects the input and output valves, I believe. And I replaced the belt recently. I wonder if the tensioner tension was a bit too tight. But my gut feeling is that it's a water pump on its last legs, and the bearing's wearing out and making whining/howling/rattling noises.
+1 on the water pump and sorry about the incorrect timing chain diag. I forget all the time these are simpler engine with belts. I prefer that anyways. I would just check to pin point the noise. It's going to be a tough one. I'm having an even more perplexing problem on my rio 09. So at least you hear a noise my car just misfires on me but without actually running rough. One other last thing to check is honestly make sure you have no vacuum leaks. Since you do have the stumbling idle as it was recommended to me in my post check your Fuel Trims. If you notice a rise in the fuel trims it usually indicates a vacuum leak. That leak could easily explain the rough idle stumbling as well as the noise you are hearing. Not a bad thing to look into.