Engine bearing advice?

[Crunch]

Pretty sure the front bearing is going out on the engine. I've been trying to track down a chirp that starts after the engine warms up. Doesn't appear to be on any of the belt driven peripherals. In the last few days the chirp has become more pronounced. Even though this is something that is probably within my skill set, I've never one it before so I'll most likely take it to the Cummins Southern Plains shop right down the street. They did the injectors a few years ago and I am happy with their work. How involved is the replacement?

Thanks for any advice.

 

[NIsaacs]

I recommend you warm it up so it makes the most noise and then pull your belt off and run it. The belt tensioner can make some weird noise when they go bad.

 

[Rowdy Dalton]

Or, a simpler solution is to warm the engine up, and spray different pulley areas with plain garden hose water. When it stops chirping, you have found the problem.
But, like @NIsaacs said, it is probably the tensioner pulley.

 

[NIsaacs]

Pretty sure the front bearing is going out on the engine.

There are several, what do you mean by front bearing? Do you mean the crank? There is a bearing in each belt driven pully on the front of the engine. After you pull the belt, test each one by spinning it. The tensioner pivot/spring can make noise when the pivot pin wears. The bounce of the belt rotation can set up strange noises, in addition to a pully bearing.

 

[User113]

Can't say I've ever heard a bad front engine bearing, but I can't imagine it making a "chirp" sound...

 

[bcbender]

more likely a fan hub bearing or idler

 

[Crunch]

Thanks for the help. I'm relieved to hear that it's probably not an engine bearing. I used an automotive stethoscope and eliminated the water pump, alternator, AC and power steering. Tensioner and fan are will be a bit tougher to get to, but I'll check them.

 

[NIsaacs]

Read this technical bulletin.

https://images.oreillyauto.com/part...98*MTY3ODc5MjM1MC4zLjEuMTY3ODc5MjU0Ny4wLjAuMA..

 

[Crunch]

Read this technical bulletin.

https://images.oreillyauto.com/part...98*MTY3ODc5MjM1MC4zLjEuMTY3ODc5MjU0Ny4wLjAuMA..

That's good reading. With 400K on the truck I think I'm going to replace the tensioner as a preventive maintenance measure. Thanks for the link.

 

[jghflys]

Have the oil analyzed at the next oil change, it will tell you what is going on with the engine internals. I use Blackstone Laboratories. Sample kits are free, the analysis is $30.00 if you send in the sample for analysis. You can sample through the dipstick tube if you want the analysis sooner than the next oil change. You can use a large syringe and a tube that fits inside the dip stick tube. There is some risk with that method though.

 

[Crunch]

Have the oil analyzed at the next oil change, it will tell you what is going on with the engine internals.

I may do that, but at this point it looks like it was the belt tensioner. The Cummins shop is just down the road from me, and they had one in stock so I picked it up this morning and installed it while the weather was still good. Started the truck and let it run for a while to make sure the belt was seated properly, then ran some errands and let the truck warm up to operating temperature. Didn't hear the chirp at all, but its absence caused me to hear all the other squeaks and rattles that a 20 year old truck has.

I also examined the old tensioner after I removed it and compared it with the new tensioner. The wheel on the old tensioner spun freely, and for quite a while when I spun it. It also had a faint friction sound. The new tensioner turned easily, but didn't really spin. It was also quiet. At this point I'm going to call this problem fixed, but keep an eye on it for a while anyway. Thanks for everyone's help and advice.