ericj628

Hello All! Been lurking and learning for a while, now making my first post.

Daughter drives a 2006 3.7L. From what I understand, based on her recollection, dash lit up and engine shut down. Couple folks helped her push to side of the road. I went to rescue to find; (a) no start condition and (b) low to no oil on dipstick. Yikes! Strap towed car home (3 miles) and started looking in to things. Added oil to proper fill level. Removed plugs and tried to hand turn motor. Little stiff, but it moved. No crank, no noise from starter. Tested entire starter circuit. Low and behold, bad starter. Removed the starter, and tested. Bad starter. Had it tested at 2 separate AutoZones....bad starter. Replaced with new starter. But, this is weird because (a) engine shut down and (b) no oil on dipstick. Perhaps just a by product of overheat, not sure. But, now it cranks. Very rough idle. Loud knocking. Shut motor down and pulled codes. P0305....misfire on cylinder 5.

So, any thoughts on what to do next? Will not be working on vehicle for a couple days. Trying to formulate a good plan before starting to dig into things.

Given that the motor may need significant rebuild, or be completely trashed, I at least wanted to dig into it to try to determine what is wrong.

Your thoughts and expertise are greatly appreciated.

regards.

lawsoncl

Compression test and maybe a boroscope would be my next suggestion. I'm going to bet on either warped head and blown head gasket, or significant engine damage. That engine does not take kindly to bad overheating.

Also, a 2006 could be a Liberty (KJ), which was confusingly sold as a a Cherokee overseas. https://www.jeepforum.com/forums/kj-liberty-forum.28/ is a much better forum for help, as the Cherokees have a very different engine.

Or it's Grand Cherokee? In which case I suggest https://www.cherokeeforum.com/f5/

ericj628

Thank You, very much! Appreciate the advice and links to the other websites. Yes, it is a GC.

ericj628

Update

Pulled the plugs, and took a close look (and smell). Plugs looked old, but not terrible. Electrodes worn slightly but not too far gone. Remember, computer showed a P0305 code, misfire on cylinder 5. And, plug from cylinder 5 was the only one different. It was darker / blacker than the others, slightly damp, and smelled very strongly of fuel.

So, did a compression test. Other than cylinder 5, all were fairly high. In fact, all were in the 150-170 psi range. Seemed a bit high to me, but maybe ok. But, cylinder 5 was around 60 psi. Another interesting point was during the compression testing of cylinder 5. On the other cylinders the gauge seemed to jump, or pulse slightly as the motor turned. On cylinder 5, there was little to no pulsing. In fact, it stayed at 0 for a bit then jumped to 60 and did not pulse. I did test each cylinder 3 times.

No luck on boroscope yet. I borrowed one from work, but it is old and does not seem to work. I’ll try to find a loaner boroscope tomorrow.

Moving forward, I’m not sure about the next step. Was considering removing the appropriate valve cover to have a look from the to side to see if there any obvious issues.

Any sage wisdom or advice is greatly appreciated.

Also, seems there is a bit of oil leaking from the front of the motor too. Perhaps a crankshaft seal, I’m not sure. Any advice on this is appreciated too.

lawsoncl

A leakdown test while rotating the crank might show if you've got a valve sticking open. Beyond that, pulling the valve cover to see what the valve is doing seems like the next logical step.

I'm assuming the 3.7 isn't like the newer 3.2l where you have to pull the intake off to get to the plugs?

ericj628

Borrowed a new boroscope from Autozone. All pistons had a lot of carbon buildup. Cylinders looked reasonable. Not the best boroscope in the world, but pretty sure I found a chunk of metal in cylinder 5. From what I have seen, it looked like a piece of a valve seat.

Pretty cold outside and lot of things going on for the holidays. Going to study up and formulate my next plan of attack. No luck on a leak down tester yet, but still looking. Game planning for valve cover removal.

Any other thoughts or suggestions from you folks are greatly appreciated. Kind of sucks, but for a guy that sits behind a desk all day it is fun to turn wrenches again.

ericj628

Update

Removed the drivers side valve cover. Rocker arms for Cylinder 5 were not where they were supposed to be!! So, another clue in the saga. Found both rockers laying down on top of the head and removed them.

So, now I am attempting to remove the drivers side head. Moving along pretty well, removing things, documenting and making some room. Now it is time to remove the intake manifold. No room. Did some digging around and determined that you need to "drop" the motor a little to be able to remove the intake manifold. OK.

So, I've got a floor-jack, some jack-stands and a couple 2x4 blocks. Any advice on dropping the motor a little? Don't have an engine hoist or any type of sophisticated jacking systems. After looking it over, seems like I should be able to add some pressure up under the motor, remove the front motor mounts and slowly drop the motor a bit. But where should I put the jack? Maybe under the oil pan? Seems risky! Has anyone accomplished this with minimal jacking equipment? Advice?

Thanks.

lawsoncl

A chunk of wood and a jack under the oil pan would likely work fine. I've done a number of motor mounts that way. Rocker being broken off is a bad sign.

ericj628

Alright, here is the next round of information.

lawsoncl .....your response inspired me and I gave it a shot. Worked like a charm! Couple soft 2x4's, stacked, and a floor jack did the trick. Backed the nut off of the motor mount bolt (passenger side) added some lift, removed the bolt, and slowly dropped the motor down enough to pull the intake manifold out. Jacked the motor back up and re-installed the bolt.

After that, kept digging. Removed a bevy of vacuum lines, electrical connectors, etc. Took off the water pump, and the timing chain cover. Did a more thorough inspection of the top of the head on the drivers side. Retrieved the 2 missing rockers from cylinder 5. Also...the cam is restrained by 4 retainers (not sure of the appropriate name). 3 of the 4 retainers are damaged. The one on the far side of cylinder 5 is completely shear off. The next 2 are cracked all the way through. Any ideas what could have cause this? I'm guessing that one of the valves in cylinder 5 did not close all the way and the piston hit the valve and the extra thrust pushed up too hard on the cam and broke the retainers....but not sure.

Next step, remove the drivers side cylinder head. I know that I will need to somehow remove the timing chain from the drivers side cam, but not sure how. Going to study up on this. Any recommendations are greatly appreciated.

lawsoncl...your thoughts have been very helpful. Appreciate it!

Thanks.

ericj628

Forgot to mention.....my plan is to remove the drivers side cylinder head and look for damage to the cylinders / pistons. If there is no damage (fingers crossed) then maybe I can get by with replacing the head. Not sure what exactly to look for when checking the cylinder / piston, but going to give it a shot.

Thanks.