Knocking noise when turning ignition on

Hey TW,

I’m hearing a strange noise from the engine compartment when turning the truck on. It does not always happen, it happens only sometimes. To me, it sounds like a knocking noise right after the truck turns over. AC is on and it usually happens after sitting out in the heat all day. Any ideas what it could be? Truck has 3k miles on it

 

open hood...have friend turn over truck...mebbe see what's up. Turn off A/C and mebbe try it that way too.

Or mebbe take um' to dealer and let them mebbe have a look see...

Welcome aboard

 

Change the climate control settings away from A/C and defrost and see if the noise is still present. Probably the A/C compressor clutch engaging

 

Oddly I have heard the same thing on my truck. Do you have a 4 banger? I have nearly 9800 miles on mine.

It's maybe happened two times to mine. I've read about piston slap but I have no idea. My truck runs fine but its a odd knock/slap for sure.

 

I do have a 4cyl SR, Same with mine truck runs great. Just an odd noise that I’ve never heard any of my previous cars make before. I’m trying to capture a good video sound of it for when I take it in for the 5k mile inspection. Lots of the other people said it might be the AC compressor clutch engaging and it’s normal

 

VVT solenoid, mebee and welcome to TW! Get some nice fresh oil into it, for sure. Good luck!