02 KJ ltd 3.7L knocking noise

[Thedevine]

Hey all! First alittle background...

Three weeks ago I pulled into my destination and shut down the KJ to find I had coolant leaking from what I can best ascertain as the water pump seal... I popped the good and checked it and started it back up and shut it down... No leak? Hasn't leaked since at least not any noticible spots where I have parked...
Filled the. Poland back up and drove, checking for leaks each stop...

Two weeks later I pull in to my home and the KJ is knocking like it three a rod or a rocker... Pop the hood.. Oils low... 3 quarts! And coolant reservoir drank a bottle too... Filled it up with oil and the knock subsided till I gave it some gas... Did oil change, air filter, spark plugs... Fired up and purred like a kitten!! Yay I thought... Till I gave it some gas... Knock remains...

I don't believe to to be valve train related and was thinking it kinda sounds like the timing chain is loose and clanking around in there but have never had this particular motor open... Anyone have thoughts on this?

I was under the impression that a loose chain or bad trnsioners would have the jeep running like poop and misfiring and such... I have not experienced any of these... The other posts about engine knocking or timin belt noises dont seem to apply to my particular problem so I went ahead with a new thread... Any help would be greatly appreciated... Thanks!

 

[jankerson]

Likely best just to take it in and have it looked at.

If it was 3 Quarts low, that's really bad, it only takes 5 Quarts so it's likely there is some damage in there. That and the combination of coolant being low also...

Could be a number of issues, reason why I suggested to take it in.....

Don't keep running it as it is though no matter what, it will just compound the problems and worst case you could blow the engine....

Better and cheaper to fix an engine that is still running than it is to buy a new engine after the old one is blown....

 

[Thedevine]

Thank you for the quick reply!!
I have mechanical ability and would prefer to tear the motor apart myself... For the experience and the walking money... And I have not been running it for fear I would cause additional damage...
I should also add that all six plugs looked gray/white indicating the moter is running lean or hot or something similar... The plugs are dry and there is no sign of coolant/oil from them nor is there any sign of leakage transfer from oil/coolant... No white smoke in the exhaust that I can see and the motor does burn a little oil from time to time... Tho when the oil changes are done on time it's hardly noticible...

Valve train sounds great and quiet... LIS seems to be in the front top of the motor and it has a distinct sound... Is it possible that one of the hydrolic pistons for the chain tensioner got stuck causing the chain to slap around but only when load is being applied or removed...?

 

[twack]

im guessing you spun a bearing with that low of oil. mine sprung a leak that i didnt notice and it ate a bearing as well. welcome to the knocking club

 

[TwoBobsKJ]

Thank you for the quick reply!!
I have mechanical ability and would prefer to tear the motor apart myself... For the experience and the walking money... And I have not been running it for fear I would cause additional damage...
I should also add that all six plugs looked gray/white indicating the moter is running lean or hot or something similar... The plugs are dry and there is no sign of coolant/oil from them nor is there any sign of leakage transfer from oil/coolant... No white smoke in the exhaust that I can see and the motor does burn a little oil from time to time... Tho when the oil changes are done on time it's hardly noticible...

Valve train sounds great and quiet... LIS seems to be in the front top of the motor and it has a distinct sound... Is it possible that one of the hydrolic pistons for the chain tensioner got stuck causing the chain to slap around but only when load is being applied or removed...?

I thought I had an issue with the timing chain(s) too. But alas... :mad3:

Engine Swap Overview...

Bob

 

[Thedevine]

Thanks for the great link! I will find out hopefully Friday when I start digging...

 

[Thedevine]

Ok so I haven't had time to tear anything apart due to the honey-dew list... I plan on dropping to oil pan and inspecting the rod bearings and crank for damage as my jeep crew's primary wrench turner came over and gave it a listen and said that's what he believes the problem is.... At least... Thank you bob for the advise u were spot-on!

My question is has anyone else replaced just the bearings from the oil pan while the motor is still in and where would you guys recommend getting the new bearings and cap bolts as they need replaced after removal... Assuming the crank isn't toast, this seems like a cheap get me by till I can save some engine buying money... Or rebuilding money depending on options...

Thanks for all ur help guys!

 

[TwoBobsKJ]

Ok so I haven't had time to tear anything apart due to the honey-dew list... I plan on dropping to oil pan and inspecting the rod bearings and crank for damage as my jeep crew's primary wrench turner came over and gave it a listen and said that's what he believes the problem is.... At least... Thank you bob for the advise u were spot-on!

My question is has anyone else replaced just the bearings from the oil pan while the motor is still in and where would you guys recommend getting the new bearings and cap bolts as they need replaced after removal... Assuming the crank isn't toast, this seems like a cheap get me by till I can save some engine buying money... Or rebuilding money depending on options...

Thanks for all ur help guys!

Unfortunately there's no way to replace the rod bearings or crank bearings with the engine still in the Jeep. The 3.7L is a two-piece block, with the "bedplate" - or lower half - holding the crank in place so you can't get to the bearings. Besides that, it's impossible to disassemble the engine, or even get the oil pan off, while the engine is in the bay.

Look through the thread in the link above and look especially at the pics of the block with the crank out and the one showing the windage tray/oil pan gasket and you'll see what I'm talking about. If you don't have the money for a reman try finding a low-mileage long block from car-part.com or your local salvage yards from a newer model year.

Ask questions as you're making up your mind!

Bob

 

[Thedevine]

Thanks for the info bob!!

Hey did u ever consider that 4.7 swap a viable option? Sounds cool but maybe not so practical... Then again no one ever bragged about practical! just curious about the option...

 

[TwoBobsKJ]

Thanks for the info bob!!

Hey did u ever consider that 4.7 swap a viable option? Sounds cool but maybe not so practical... Then again no one ever bragged about practical! just curious about the option...

No, never considered it seriously. I figure with a regear I'll get the kind of performance out of my KJ that will keep me happy doing what it's designed to do.

However, there is a certain '73 Roadrunner I'd like to put a 426 into ... eace:

Bob

 

[Thedevine]

Pulled the motor and got it on a stand. Removed valve covers and the right side timing chain is loose... The top side I.e. the none tensioner side of the chain... Haven't got the oil pan off yet... Question would the chain be loose in that manner if the tensioner failed? I would think the way the motor turns that the chain would be loose on the back side of the pull... The motor turns clockwise so wouldn't the section I'm describing be tight and the slack should be on the none pull side... I don't know anyone have any thoughts on the matter? Thank you

 

[Thedevine]

I'm also having trouble locating an m14 Allen head cap bolt to pull the harmonic balance wheel... And I'm unclear asto whether it should be longer so as to go into the crank or should it be short and avoid the crank threads... Have conflicting views on this so has anyone don't this before and what did u use? Thanks

 

[TwoBobsKJ]

I'm also having trouble locating an m14 Allen head cap bolt to pull the harmonic balance wheel... And I'm unclear asto whether it should be longer so as to go into the crank or should it be short and avoid the crank threads... Have conflicting views on this so has anyone don't this before and what did u use? Thanks

I went to the local AutoZone and rented a puller that is designed to pull the balancer on Chrysler engines. Has an insert that goes over the nose of the crank and three arms that hook over the tabs on the balancer. Had the balancer off in 10 minutes.

Bob

 

[Thedevine]

Got the timing cover off. Used a 3jaw puller and a modded bolt I drilled out... Timing chain tensioner on right side is not sitting against the built in ratchet arm stop... Im thinking the chain is stretched but don't have the measuring tools yet to check...

 

[Thedevine]

Update:
Found a bad rod bearing in time and replaced all six with STD's and put it all back together... Motor is back in and running! Having trouble getting the motor to drink all the coolant... Had the motor turned over and I believe most of the coolant was drained so I'm not sure why it only took about 9.45 liters(calls for over 14!) so I'm pretty sure it's got some air trapped... Was getting heat from the core and had it warmed up and shut it down... The level never dropped so I guess I'll have to drive it around the block a few times and see if that helps get some air out... ( any thoughts on this would be appreciated) aside from that the motor sounded good and no more rod knock! Woohoo!! Thanks for all the assistance!

 

[twack]

Update:
Found a bad rod bearing in time and replaced all six with STD's and put it all back together... Motor is back in and running! Having trouble getting the motor to drink all the coolant... Had the motor turned over and I believe most of the coolant was drained so I'm not sure why it only took about 9.45 liters(calls for over 14!) so I'm pretty sure it's got some air trapped... Was getting heat from the core and had it warmed up and shut it down... The level never dropped so I guess I'll have to drive it around the block a few times and see if that helps get some air out... ( any thoughts on this would be appreciated) aside from that the motor sounded good and no more rod knock! Woohoo!! Thanks for all the assistance!

very interested in how this turns out, keep us posted as you add some miles!

 

[CactusJacked]

Do you plan on keeping this car for a while? A bad rod bearing can also mean a bad crank journal. The crank should have been removed, taken into a machine shop and checked. Sometimes you can get away with just a polish and use the same size bearings. Other times there's enough journal wear to where the crank needs to be turned down and undersize bearings are used. I suppose you didn't check your new bearing clearances with plasti-gage either? I'd be curious enough to install a mechanical oil pressure gauge and see where the pressure is at.

 

[Thedevine]

Journal clearanced in spec... Plastigauge confirmed this... All back together now and running... I know it's a bandaid fix and plan On replacing the motor w a reman in a year just don't have 3k laying around... The oil pressure gauge is a good idea... At least I could keeP an eye on things in cause I screwed up... I do have an exhaust leak to fix yet I think I may have damaged the gasket on the drivers side down pipe flex joint getting the starter motor out... And the alternator is squeeling... Musta cleaned it up too well... Lol other than that it seems to be running fine... Still hasn't drank as much coolant as it should have... Damnedest thing still rackIng my brain...

 

[TwoBobsKJ]

If you don't have the $'s for a reman you can always use a 3.7L out of any Chrysler product through at least 2011. Its not a direct swap but since you're obviously handy tearing an engine apart you should have no problem getting a very low mileage 3.7L and doing a couple of mods and installing it in your Libby.

Check out this thread on the process I followed to put in a block from an '07 Dodge Dakota into my '03 KJ. The engine cost me $1000 and it only had 9700 miles on it.

Just a thought...

Bob

 

[profdlp]

I just wanted to say that I am in awe of you guys who can do this stuff. Someday I hope to learn. :waytogo: