Crank issue when trying to start...

[pelted]

I had a chance to have someone else try and start the 3.7L Liberty while I looked down inside. When the key is turned I can see the harmonic balancer very very slowly starts to turn. This is without the accessory belt attached. I've not had any battery or starter issues. It was starting fine then I replaced the fan clutch after an overheat (this was after a water pump replacement then a test drive). Basically, overheated, replaced pump and thermo, then fluid, test drove, and it overheated again, then let it cool down and I put the new fan clutch on and this cranking problem is now here.

There doesn't seem to be any outward sign of some catastrophic damage or failure like a thrown rod, head gasket issue or anything like that. There is no oil or fluid leaking and levels look good on everything. Trying to hand crank the engine is very hard to do, but it does move. Could this be over pressure and can it be relieved somehow? Any other ideas?

 

[TwoBobsKJ]

I had a chance to have someone else try and start the 3.7L Liberty while I looked down inside. When the key is turned I can see the harmonic balancer very very slowly starts to turn. This is without the accessory belt attached. I've not had any battery or starter issues. It was starting fine then I replaced the fan clutch after an overheat (this was after a water pump replacement then a test drive). Basically, overheated, replaced pump and thermo, then fluid, test drove, and it overheated again, then let it cool down and I put the new fan clutch on and this cranking problem is now here.

There doesn't seem to be any outward sign of some catastrophic damage or failure like a thrown rod, head gasket issue or anything like that. There is no oil or fluid leaking and levels look good on everything. Trying to hand crank the engine is very hard to do, but it does move. Could this be over pressure and can it be relieved somehow? Any other ideas?

Welcome to JeepKJ.com (welcome)

These 3.7L engines don't take to overheating very well - leads to all kinds of issues from valves dropping to head gasket leaks. I'd be concerned that since yours overheated twice that the engine has seized - one or more cylinders and pistons are bound up due to excessive heat.

Could also be water/coolant in one of the cylinders; in either case the only way to tell would be to tear it apart. At that point you might as well just put in a new/used engine.

Doesn't look too good either way :boxed:

Bob

 

[pelted]

Well this is a rebuilt engine, that's been in there for a couple of years now and been great. Shop that did it was pretty good. I don't know much more about how to diagnose this. My plan now was to pull the plugs out and see if pressure could be released, this was based on some reading. Any suggestions to try before having it taken somewhere and spending a bunch of $$ to find out?

 

[TwoBobsKJ]

Well this is a rebuilt engine, that's been in there for a couple of years now and been great. Shop that did it was pretty good. I don't know much more about how to diagnose this. My plan now was to pull the plugs out and see if pressure could be released, this was based on some reading. Any suggestions to try before having it taken somewhere and spending a bunch of $$ to find out?

Yep, pull the plugs and see if it turns over correctly. If that doesn't work then off to the shop I'm afraid...

Bob

 

[pelted]

Well I pulled the plugs, and the middle on on the passenger side had coolant on the plug. The other were dry and looked good. When I hand cranked the motor coolant blew out of it and it turned well. At this point I'm leaning towards head gasket and thinking of trying that sealant stuff for now. At least long enough to have the car for occasional use and to get me through a trade in. I'd love to keep my Liberty but a new Wrangler is looking pretty tempting.