My 2006 Jeep Liberty CRD with 108k on the odometer is having starting issues, and I'm looking for assistance in diagnosing it. YouTube video linked below, temperatures 42⁰ F and the block heater had been running prior to video. It usually fires right up, but lately it occassionally stops cranking abruptly with a loud clank. It seems to only occur after sitting for a week or so. After sitting for this long it produces an extensive white cloud of exhaust while driving until it is warm. My initial thought is that it is the starter clutch, but I've been slowly losing coolant for the past couple of years so I'm wondering about hydrolock. My oil analyses have been showing sodium in the oil, so assumption has been that coolant is leaking into the oil through head gasket. However, Oregon Fuel Injection found no indication of head gasket leak when they looked at it in 2018. I just replaced the battery with a Group 65 AGM battery with 930 CCA to rule that out. OBD2 scanner is not showing any codes. Thoughts?

https://youtu.be/pH6uurIsdEg

yes it does sound like hydraulic lock ,, remove Glow plugs and pressure test cooling system,

You're probably right about the hydro lock, as the one I had recently with a leaky injector (put ounces of diesel in one cylinder) sounded similar. It couldn't compress the juice...
Can pull the glow plugs and see if any coolant comes out when you crank it. Just pull the injector fuse under the hood first and crank away.
Mine also "backfired" just like yours did, cant forget that sound.

You will have worn out rockers (99% chance), so your engine needs the royal treatment...

Any more cranking may bend a rod, or snap the starter gear like it did in mine. Do not start!

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05 CRD: H.D.S2 stat,WW Ironrock trilink&LCA's, OX rear,ARB front, 4.10's, ARB bumper, Suncoast,OME 3.5, JBA UCA,rock rails, Moabs&265/75 Duratracs, GDE tunes ,FFD fan,ARP's, 2 micron fuel, new valves,sasquatch battery tray & grid heater, tensioner relocated
Mech fan, VH & AC delete

I neglected to ever post a follow-up: in my case, it was just a poor connection with the battery that was occasionally dropping the amperage mid-start.