2008 JKU engine rattle

Started the Jeep this morning and it had a rattle that I thought was a serpentine belt tensioner pulley bearing. I removed the old one and checked it out. It really didn't seem worn out, but they are cheap enough I went on and replaced it. New one on and still had the rattle. I removed the belt again and checked everything out. Everything seems tight except for the power steering pulley. It has in and out play. I reinstalled the belt and started it again and listened to try to get a general idea of the area. It sounded more like the alternator area. I removed the belt again to check everything out. Everything on that side is good. I decided to start it this time with the belt off. It still had the rattle. Drivers side of the engine. Here is a video of the sound. https://youtu.be/bo-4OV-VV0g

The engine oil is fine and I have 55psi oil pressure when started. Anyone have any ideas?

 

I let it run long enough to warm up to see if the sound changed or went away. It seems unchanged. I did notice you could hear it better with the hood down. I moved closer to the drivers front wheel well and it seemed closer, but that could have been just because the hood was closed. Here is another video and you can hear it really clear.

https://youtu.be/cbUIG4PRg_I

 

After a couple of days of searching and reading, I am leaning toward it possibly being a spun rod bearing. Can anyone tell me if this sounds the same?

 

Welcome @MBK_0|||||||0 ....can't quite make a guess on the sound/rattle. Hope it's a external source like bearings, pulleys, vacuum leaks, etc. Taking off the accessory belts make sense. Might want to try a stethoscope to try isolating the sound.

 

Welcome to the forum @MBK_0|||||||0 .
Very hard to tell from your video posts. Sounds like a cross between a bad bearing and a vacuum leak. Or a bad valve tap. One of those issues. You gotta be there. Hard to tell if its externally or internal. I'd give the stethoscope a shot as @aggrex mentioned. Hope its a cheap fix for ya.

 

I finally got a few minutes to use the stethoscope on this. Everything has some sort of noise to it. It wasn't until I touched the bell housing (auyomatic) that I heard the sound I was looking for. I hope to get time to get it up on ramps in the next day or two to see what it looks like. Hopefully a bolt backed out and it hasn't hurt anything yet.

 

Inspection plate/cover removed. No metal shavings behind it. No bolts loose going to torque converter. Basically it looks normal. I got the stethoscope back out. The oil pan is quiet high up and down low. The only place I got the sound was where the engine and transmission come together where the inspection plate was removed.

It is almost time for an oil change, so I went ahead and pulled the plug to take a look. Nothing out of the ordinary. The plug had no metal on it. The oil had no metal in it. I even put a magnet in the drain pan and it didn't pick anything up.

It sounds like a rock or marble rattling around. Could the starter gear be stuck in the out position without having a whiney sound to it?

 

Got home before the storms today. I changed the filter and put new oil in it. Started it and grabbed the stethoscope. The rattle was still in the same area. No reason for it to move, right? Haha I revved it a little to see if the sound changed any at all. After a few revs it started to change sound. It turned into a light squeak. Out again to listen and can't figure it out. I turned it offso I could look around a bit to see what else I could check for the sound. When I got in to start it again, nothing. The starter doesn't even make a noise. No crank, nothing. I don't even hear it click from sitting in the seat. Maybe I broke the starter...

It looks like the storms have set in for the night. Back at it tomorrow afternoon hopefully.

 

If it turns out to be the starter then replacement is straightforward. Maybe it will fix two issues with one shot.

 

@aggrex Thanks. I've checked out a couple of videos on the starter. One made it look like there was a lot of room to work. I bet it isn't even enough to get one hand in there. Shouldn't be too bad though. I am going to get the meter out first and make sure it isn't a totally different issue before taking the starter out.

 

12V directly to the starter and getting something or nothing could explain things.

 

Not that this has anything to do with your "noise hunting". But 4 times out of 5 times. The issue with not starting. Is not the starter. It's the battery. These new batteries these days give you no warning. They just go. The fact that you didn't hear the "click" when you sat in the seat. Tells me it's a battery issue is present. See if you can jump it. Test alternator. If output is good. Then shut it down and test battery. Sorry i cant help with your noise issue.

 

@JKBob 25 I agree on the battery. I drove to a store in my truck one day with no battery issues at all. I came out and it wouldn't start. The gauges went haywire. I went back in and bought a battery to fix it. No warning at all and it wouldn't jump start when it happened.

 

12v thru the solenoid got nothing. 12v straight to starter made it spin. It isn't locked up, but it definitely needs replaced. The gear just flops around wherever it wants. The shaft is discolored like it has been very hot.

 

Teeth on ring gear look worn with some unusual contact. Compare the looseness with the replacement starter as it could be the source of the rattle.

 

Looks like that one out of 5 times. Your starter could definitely be an issue. At least the solenoid anyways. I don't think the discoloration is an issue as jeeps tend to run hotter than most vehicles. A couple hard starts in the summer could cause that over time. And the sloppy play with the ring gear. If I'm not mistaken. There's a spring behind it. Worn out spring explains that. Either way. Probably a good idea to replace the starter.

 

Problem seems to be solved. I installed a new starter this afternoon and the rattle is gone. That job was almost as bad of a PITA as changing the EGR valve on the back of the engine.

 

Did the rattling ever come back?

Thanks for all the updates!