Chattering coming from crankshaft pulley
 

Hello everyone! First post here.

I recently bought a 2008 ford ranger xl 4x4 with the 4.0l engine and auto trans. It has 119,000 miles. I've been doing all the regular maintence stuff (oil change, coolant flush, rear diff fluid, transfer case, etc). Everything was going fine until i started to hear a squeal coming from under the hood. I pinpointed the squeal coming from the tensioner pulley. I replaced the tensioner, idler, and belt with new ones. Squealing stopped.

I was happy and ready to start daily driving, right? Wrong. 2 weeks later, i start hearing another noise coming from the front end, but this time from a lower area then before and it was no longer a squeal, but more of an inconsistent "chattering".It's very quiet and can BARELY be heard. I've isolated the noise and i believe its coming from the crankshaft pulley. Also, it only starts chattering when im in drive. Any input, ideas, or responses will be greatly appreciated.

Also, could this be the start of a more serious problem? Truck drives and shifts smoothly. So im hopeful that this isnt a tranny issue or something else more serious/expensive. Im relatively new to working on vehicles but have managed to do all the maintenance myself up until this point. If you took your time to read this THANK YOU!!!

Welcome to the forum

When engine is STONE COLD
Take fan belt off crank pulley

Have a friend start the engine, Battery Light will stay on
Engine bay will be very quiet with no fan
See if crank pulley is spinning straight
Have friend put it in drive or reverse

You can run the engine for no more than 2 min without water pump, less is better, but you can do it as many times as you want after letting it cool down

Power steering pumps on Fords are noisy beasts
Alternator bearing can start to growl

Thanks for the response.

When i replaced my belt, tensioner and idler acouple weeks ago i noticed that when i spun the alternator pulley by hand, it made a small squeak and the power steering has a very small amount of horizontal play in it. Could this possibly be making it sound like the chirping is coming from the crankshaft?

I will take the belt off this weekend and start it up to see if the crankshaft pulley is straight. Sorry for the newb question but the crankshaft pulley will spin without the belt on right? Which will make it easier to diagnose because less noise and movement coming from other parts?

Yes, crank shaft pulley is the Drive pulley for the belt, it spins everything less on the belt, so it will always turn when engine is running

But very important to not run the engine very long this way, check for the noise, and any wobble, in Park and in gear, then SHUT OFF the engine or it will overheat