What's squeaking?

[AMink]

I have a relatively new squeak coming from the front of the engine. At first I thought it was the new vacuum pump for the Jake brake"is coming from the alternator side of the engine. How can I tell if it's the alternator, tensioner, or a/c? A lot of noise with the engine running to tell for sure. Belt is new within the last year. It squeaks like my old 12v on shut down but had been since the belt was new.

 

[Prairie Dog]

Remove the belt and turn things by hand. If that doesn't lead you to anything then buy a cheap mechanics stethoscope from JC Gipme and listen to each item.

 

[MMeier]

My $$$ is on the tensioner... if I had any $$$

 

[AMink]

I took a shot and replaced the tensioner. No more squeak! The old one's pulley was a little worn (it's plastic) and the new one seems a bit tighter. The massive squeak on shutdown also seems to have been reduced.

For those who do this in the future...take the air box out. It gives you a lot more room to stick your arms. Same when you change the belt.