Knocking on startup
 

Lately, on a cold start I will hear a loud knocking sound coming from the engine compartment. It will last about 1-2 seconds, and then everything is normal. It's happened twice in the last couple of weeks. Any idea what it might be?

It's a 2002 manual shift with 45K on it.

Is it really "knocking" or do you mean tapping - as in the hydraulic lifters pumping up? Which is not uncommon with a cold engine and dirty or old oil.

Well it's not high-pitched, so I would call it more of a knocking sound. However, it could be a lower-pitched tapping noise. Not sure what the lifters reallly sound like. It would make sense, though, considering it's only on a cold start.

Okay, I tried something else. I tried to start it with the clutch out, disabling the engine from starting or turning over.

It did the same thing, so it's definitely not the engine. Seems to be coming from the engine compartment. My guess is that it's something to do with the starter, although it didn't turn the engine over, so I have no idea.

Yeah that's normal if it is what I'm thinking it is. It does it when I turn the ignition on to check the oil level, ect. I don't know what makes that noise, but it's normal.

Well that's good. Not sure why it's only started lately, though. I guess yours has done this for a while without ill effects?

Yeah, it has done it since new. When you turn on the ignition without actually starting the engine like to check oil level for instance, I can hear several accessaries power up and activate. One of them is the sound you are describing. It's obviously something receiving power, but I don't know what it is. Maybe somebody else can tell us here.