yay for rod knocks!

**Rodeo1488** · 04-08-2008, 10:16 PM

Eratan, welcome to our humble abode. Hope you enjoy yourself. make sure u fill out your profile info for us, so we can better help you in the future.

I had (what I thought) was the same issue. I found out that it was a rocker arm just needed to be torqued back down. it has started agin tho, so I may have to replace the rocker arm(s) or just add a washer to torque it down again.

flkeysff · 04-08-2008, 10:20 PM

There seem to be quite a few (including myself) who have 2.5L that knock. I guess this is a common occurance. I am interested to find what you have when you pull the pan. Please keep us informed. Mine developed it's knock after an oil change.

But I keep on driving. I figure I'll fix it when it breaks.

flkeysff · 04-08-2008, 10:23 PM

Quote:

Originally Posted by Rodeo1488

Eratan, welcome to our humble abode. Hope you enjoy yourself. make sure u fill out your profile info for us, so we can better help you in the future.

I had (what I thought) was the same issue. I found out that it was a rocker arm just needed to be torqued back down. it has started agin tho, so I may have to replace the rocker arm(s) or just add a washer to torque it down again.

Did your knock sound come from the bottom of the engine? I hear mine in the engine compartment but it seems louder by the oilpan. I have thought about the rocker arms but I would think that would sound more like a tick than a knock. Also did it go away when you stepped on the gas? Thanks

**Rodeo1488** · 04-08-2008, 10:44 PM

Mine did seem to go away when I added gas. I had to replace the valve cover gasket and when I took the valve cover off, I could really hear the rocker arm ticking.

eraten · 04-08-2008, 10:45 PM

Quote:

Originally Posted by flkeysff

Did your knock sound come from the bottom of the engine? I hear mine in the engine compartment but it seems louder by the oilpan. I have thought about the rocker arms but I would hink that would sound more like a tick than a knock. Also did it go away when you stepped on the gas? Thanks

Yes, when I stepped on the gas i flinched because I thought i'd hear the engine knock faster... but to my surprise when I rev it up passed 2k the knocking sound stops. I've had two vehicles that have had rod-knocks, one was a slipped rod and lasted about 3 days the other was a cracked rod which lasted well over 2 years. With both of those the knocking sound increased and decreased with engine speed... which is why I'm hesitating to think this is just a rod heading south for the winter.

eraten · 04-08-2008, 10:56 PM

Quote:

Originally Posted by flkeysff

Did your knock sound come from the bottom of the engine? I hear mine in the engine compartment but it seems louder by the oilpan. I have thought about the rocker arms but I would think that would sound more like a tick than a knock. Also did it go away when you stepped on the gas? Thanks

Also, with that damned fan blowing it's hard to tell where the sounds coming from. it sounds loud all over, I did the ol' ear to the screwdriver trick that my dad taught me but I'm not hearing any difference in sound from the front to the back of the engine. I heard something about a piston slap that will "go away" with higher engine temps and will be unheard with higher revs... either way I'll be taking this engine apart pretty soon :-/

**Alabamaranger** · 04-08-2008, 11:54 PM

My son had a 98 TJ with the 2.5. It started knocking when you let off the gas. It was a weird knock coming from the middle of the engine. Anyway pull the pan and put in new rod bearings. Started it back up and it started knocking again. Pulled the pan again this time I found parts of the piston skirt in the bottom. Took the head off and I had 2 pistons with cracked skirts. Seem to be a common deal with the 2.5. Put 4 new pistons, rings, honed out the cylinders and good as new again. I did find out the the 4.0 pistons are the same as the 2.5 pistons.

So when you pull the pan off, get a good flashlight and look up those skirts, I mean look at those skirts.

.

eraten · 04-09-2008, 12:36 AM

Quote:

Originally Posted by Alabamaranger

My son had a 98 TJ with the 2.5. It started knocking when you let off the gas. It was a weird knock coming from the middle of the engine. Anyway pull the pan and put in new rod bearings. Started it back up and it started knocking again. Pulled the pan again this time I found parts of the piston skirt in the bottom. Took the head off and I had 2 pistons with cracked skirts. Seem to be a common deal with the 2.5. Put 4 new pistons, rings, honed out the cylinders and good as new again. I did find out the the 4.0 pistons are the same as the 2.5 pistons.

So when you pull the pan off, get a good flashlight and look up those skirts, I mean look at those skirts.

.

alright, I will update this probably friday afternoon and let you guys know what I find, maybe even post some pictures to help someone out who's having the same issue. my biggest fear was that I was going to have to take the engine completely apart, but if it's just a cracked skirt I'll be happy. maybe this is why I was getting a bit of oil out of the valve cover up through my air filter. thank you guys so much for the help, I'm glad I found this forum!

eraten · 04-09-2008, 05:32 PM

after a full nights sleep and a clear mind I took another listen and it sounds about twice as loud of a knocking sound coming from the bottom... could be a bad bearing or a lifter maybe? any ideas? and after I turn the engine off I can hear a clanking sound for about 3 minutes about ever 3 seconds exactly.

**Alabamaranger** · 04-09-2008, 05:37 PM

If it's a rod bearing, remove one spark plug wire at a time. When you remove the wire, you are removing the explosion inside than reducing the push on the piston.

When you do this it will reduce or stop the knock on that cylinder so you will have an ideal on which one to look at when you drop the pan. Crack skirt will still make a noise but it should be reduced a little.

Don't get ZAPPPPPPPPPP.......

eraten · 04-09-2008, 05:49 PM

Quote:

Originally Posted by Alabamaranger

If it's a rod bearing, remove one spark plug wire at a time. When you remove the wire, you are removing the explosion inside than reducing the push on the piston.

When you do this it will reduce or stop the knock on that cylinder so you will have an ideal on which one to look at when you drop the pan. Crack skirt will still make a noise but it should be reduced a little.

Don't get ZAPPPPPPPPPP.......

I wish I would've listened to your warning to not get zapped... only happened twice though

it doesn't seem to make a difference... I hear the knocking sound regardless... it does slow down however with each plug I pull.... (it's a four banger I'm suprised it even ran on 3

)

eraten · 04-09-2008, 07:05 PM

pulled my oil pan out (didn't need to move the tranny or exhaust... it was a tight fit but everything came out just fine) can't see anything up there so I'm pretty sure I just wasted my time.... but now I know it's probably a stuck valve clankin around up top so I s'pose its time to start shoppin for a rebuild kit for my head. or maybe just buy a new/used one... but rebuilds are always fun and cheaper! any good online stores with good prices on rebuild kits? or possibly even just a new head?

**laybackman** · 04-09-2008, 07:39 PM

Quote:

Originally Posted by eraten

pulled my oil pan out (didn't need to move the tranny or exhaust... it was a tight fit but everything came out just fine) can't see anything up there so I'm pretty sure I just wasted my time.... but now I know it's probably a stuck valve clankin around up top so I s'pose its time to start shoppin for a rebuild kit for my head. or maybe just buy a new/used one... but rebuilds are always fun and cheaper! any good online stores with good prices on rebuild kits? or possibly even just a new head?

This may help :
http://www.jeepforum.com/forum/f11/rod-bearings-question-531931/#post4944488

bigh20rnr · 04-09-2008, 08:14 PM

If its from the lower end if you still have your pan off may want to check the main bearings to see if they are worn, a wandering crank can cause some strange noises. I have not had a jeep with that engine since 94 so not a lot of experience with it and just a thought.

Rick