Terrible noise in motor

[m-remington-05]

I have a 97 explorer with a 4.0 motor with 160,000 miles. I keep it well maintained and it has been a great running rig. I went to the store yesterday and when I turned the key on the most god awful noise was there. It's like the sound when a kid puts a baseball card in the spokes of a bike, only much louder and more metalic sounding.

I was wondering if anyone has any ideas what it could be. There is no diffrence in power, as I had to drive it ten miles home. I have tried to pinpoint the noise but cant. The closet I can guess is the top center of the motor. A friend mentioned a possible collapsed lifter.

Anyone have any ideas?

 

[Willard]

Is it the 4.0 SOHC or OHV?

 

[m-remington-05]

It's got the single over head cam.

 

[Willard]

Well, it almost sounds like the starter is stuck a little and grinding on the flywheel.

Either that or you have internal timing chain problems.

Since your truck is SOHC, you have no lifters.

 

[m-remington-05]

Thanks for the quick reply. I was also wondering about the starter sticking. If I had a chain problem would it all of a sudden do it all at once? Also, shouldn't there also be a change in the way the motor runs?

I wish I had a stethoscope so I could pinpoint it. I did go out after your post and it sounds very loud under the truck near the flywheel. If I could get my hand on the starter while running I should be able to feel it, correct?

I'm not much of a mechanic as you see, lol.

 

[m-remington-05]

I couldn't really feel any vibration on the starter but the sound is very loud down there compared to the top of the motor. Is there anything that can go wrong with just the flywheel that doesnt involve the starter. This starter looks to be a real chore to remove.

 

[estwing17]

terrible noise

It's your timing chain tensioner. My story exactley! The front timing chain tensioner broke and the carcass is hitting the timing chain. My mechanic showed me the broken piece of plastic looking into the oil fill cap. I am considering trying to replace just the tensioner myself. I have know idea if just the tensioner can be replaced without doing the whole cassete and or the jack shaft chain .