Metallic noises from my 4.0 (Solved!)

[Old Yeller]

Well, dave got me out jeeping on Friday night, and he got REAL stuck. He ended up blowing up a front axle, and I had to rescue him. (Much to my delight, btw)

Anyways, after it was all over at 8:30am, the next morning, and everyone was back, I found that besides my failed alternator (now replaced) I have an alarming knock/tap coming from my jeep at idle. It is in the immediate vicinity of the engine, and ruled out any exhaust issues. It speeds up with engine speed, and is putting my jeep jam plans in jeopardy.

Anyone in the halifax/dartmouth/sackville area that has experience with these engine noises? APJ's would be my best bet, but my work schedule doesn't allow for me to head there.

I am fully prepared to have to swap out motors, being at 308k and all, but I would be delighted if it was something not as serious. It sounds like a metalic tapping from the lower end of the motor, but it is hard to pinpoint. (for me anyways)

Rob D

[toplessrubi]

a hose placed on the block in several locations should help you narrow things down use it like a (stethoscope).

John

[projectnightmare]

or a broom handle... it works! watch out for the spinning fan and alternator belt.

[Hawkes]

Jun 1, 2009 3:26:48 GMT -4 @projectnightmare said:

or a broom handle... it works! watch out for the spinning fan and alternator belt.

I use a wooden broom handle, (without the broom head). You can listen to each cylinder this way. Sounds like crank bearings, but could be anything.

Any loss of power? If the noise is closer to the top of the engine pull the valve cover and check the rockers, they wear where the push rods ride on them.

[Old Yeller]

There doesn't seem to be any loss in power, and the noise is most noticable at idle, just when you first hit the throttle. I'm dropping by APJ's later today to get it diagnosed. People are telling me crank bearings. IF this is the case, do you need to pull the engine? or can you get at them by removing the oil pan and bearing caps? Never worked on the internals of an engine before, so I may be way off.

Rob D

[Creepy]

its not a crash course in brain surgery! Does it sound like its riding the lightning, or trapped under ice? Perhaps the battery has a damaged case? The wait during the small hours may make you feel helpless, but escape the creeping death and fight fire with fire b4 the JAM fades to black



well with that out of the way...

got a real oil gauge? Zero at idle? (you only need a few #'s.)

if you have ok oil pressure, maybe its a collapsed/stuck lifter or bent pushrod. did you get into high rpms on the recovery?

the increasing tick tick tick with rpm is usually valve train related. its twice the engine speed if you can disingush that, but its tough.

You can measure lifts at the valves with a dial indiactor, should be easy to see one not opening.

again, that is if your oil pressure is good.

[Old Yeller]

Oil pressure is the same as it was before the knock started. Just over half way around the gauge at speed, and about quarter at idle. The noise is really only bad at idle, and bliping the throttle, at speed it is faster and much quieter.

Dropped by APJ's today, and of course they are busy as hell with the jam coming up and all. It would be silly to pay shop rates to find/fix the problem anyways, as these engines can be had for a few hundred dollars for a good used one.

The sound is much louder when you crawl under the jeep, than listening up top, and it is more than just a tick, more of a clacking noise. Lower end bearings or crank, or something of that nature. It doesn't really matter as it is going to be easier and more time conscious to just do a swap.

The swap is likely this week if a sound engine can be found quickly. You got a PM back Jan.

[tchase]

Torque convertor bolts? Mine backed out on my '91 resulting in a diagnosis of bad crank bearings by quite a few people.

[Creepy]

ohh yeah, check that!

[Stevens]

Seen some cracked flex plates that make this noise as well. They crack around the center bolts.

[Old Yeller]

I just had a pinge, of what do you call it .... hope? lol

I will certainly pull the cover off tomorrow, and have a look see. It could even make sense, since the tranny was replaced by myself 50k or so ago, and possibly a bolt or two could have backed off. Not getting my hopes up too much though.

Thanks guys!

[Hawkes]

Jun 1, 2009 20:37:06 GMT -4 Old Yeller said:

I just had a pinge, of what do you call it .... hope? lol

I will certainly pull the cover off tomorrow, and have a look see. It could even make sense, since the tranny was replaced by myself 50k or so ago, and possibly a bolt or two could have backed off. Not getting my hopes up too much though.

Thanks guys!

Good luck!

[Old Yeller]

Checking now. I'm too curious to leave it.

[Creepy]

im in suspense!

[Old Yeller]

Gotta be careful giving out advise like that tchase....



Some strange jeeper is liable to come over to your house and give you a hug! haha

Here is what I found:


This one was the worst, but all 4 had back out at least one turn. I cranked them on tight, fired it up and breathed an expensive sigh of relief!

308k? Pfft, this engine is just getting going. She is bound to hit 600k now! Thanks everyone, and especially tchase. You may have jipped Jan out of a sale however lol!

Rob D