The Mystery Of A 6-year-old Engine: What Caused This?? 

Just a guess on what might have happened to this engine. It may have had a core shift during casting. Machining the bore .020” oversize further reduced the wall thickness. Through time and heat a crack started to develop. When the coolant leakage was small it flashed off during combustion cycle (may have caused a misfire) but still ran okay. Eventually the crack grew large enough that when the hot engine was shut down, the still pressurized coolant system would start to flood the cylinder. Now every restart of the engine had varying degrees of hydrolock hammering the piston. It started to crack and then failed completely. The engine probably overheated because the owner was unaware of the coolant loss. It would be interesting to look at the valve seats in the failed cylinder and see if hydrolock caused any mushrooming. There may not be enough wall thickness to support a liner sleeve. You’ll find out when it’s bored out! Absolutely love your channel and the every day common sense you apply to your work. Keep it up!

I find most all of your videos interesting. Probably not the only one. ;)

Your fine your such a good story teller I’d set hear and listen to you explain shoveling cow crap . Your what’s called a natural. There’s slot of other people talking about the same thing but so far your the best

Assembled pistons & rods.. Dex, I'd be interested in your idea to sell sets of used rods with new pistons already installed. with option to core exchange old rods. Love your channel! Keep up the great work. More videos of having fun off-road with you guys please.

I been Turing wrenches 20 yrs I bet it was run hot bad fan thermostat etc it cracked the block it sat around a while it leaked the coolant into cyclinder 2 threw crack they tried to start it and other cyclinders fired and exploded the piston in 2 end of motor

Keep doing what you do. Each engine has its own challenges, so don't worry about doing same kind of engines. 😊😊😊😊😊

Keep em coming no matter what.

T4U Trick 4 You - welding cast experiment, The hole in the block lets say, if you weld the piece around the edge where you would stitch it naturally and weld around the edge where you would stitch it on the block then place the piece into place then stitch them together - so each has weld on them around the perimeter and you don't rush keeping it cold as possible then spot weld slowly into place like 22 gauge sheet metal, Hope that makes sense trying to keep it cold / tack welding slow / then final should be no stretch and hopefully no cracks, It did work for me and i hope you can use it but i still hate cast welding lol cheers love the info and comedy, good luck

Awesome channel. I second the fact that you’re a great story teller. Not saying you’re spinning yarns but you can verbally walk us through what you’re thinking. On a side note, your brother definitely adds to the videos. Thanks for the content and all you do.

I think it ingested something laying in the manifold. Nut, bolt, chunk of the old motor, ect...

“Are you seriousin me?” 😂😂

Love your videos man I love Jeeps and learning more about them, I have a 96 5.2 zj, be cool to see some videos on a v8 🤘🏻🤘🏻🤘🏻🤘🏻

Hypereutectic has a higher silicon content which makes them lighter and less expanding than average cast aluminum or forged

Fram extra guard.... Orange Can Of Death 😅

I like all your videos

Super interesting video I bet when they pressed that piston pin in they cracked iy because they used a v block to hold it didn't get it on there right as opposed to that rounded holder just for 4.0 pistons like you have

Nickel rods are used to weld cast, last i bought was close to $400 a can or preheat and then weld, then reheat slightly every few minutes to control temperature drop. Wrap after multiple times with heat blanket. If done correctly, it will work

Wowzers! I think this is the best looking used engine I’ve seen.... until you took it apart. Lol.

I got a wj and I think it needs a lifter.. or maybe a motor.. 392 swap?

All I can say is that I just had a motor in my own J+ep do this to And look the same as this! And one of my guess is that the oil was clean because it was just change !! after Not changing it for a really long long time . The motor run strong in tell i change the oil and drove home and the next day went to drive it and it started tic tick tic really loud ! so I started looking the Motor over did not find anything so I stopped looking and started the Hard drive test intel! just like what you got there !! But just like you I also keep old Jeep parts around .

Got any good places to order full 4.0 rebuild kits for a 2004 with power seal pistons

Maybey the cylinder cracked first allowing coolant to enter the cylinder hydrolocking the cylinder breaking the piston? Just a thought?

Would love to see you guys work on a Northstar V8 I know they're pretty notoriously bad haha

the only thing i could think of is maybe ring land failure and it was driven hard enough when it happened for it to break apart, would be my best guess at the very least

What kind o' flashlights are you guys using here?

That FRAM filter unlife it. wix filter, Valvoline oil. 335k 96xj I've put 150k on the clock

Low oil flow wore piston casting apart unless spark plug touched

maybe make a video of welding the block?

Dex, been watching you forever now… I’ve been having some issues with my 99 Cherokee 4.0 for 3 years now. But I’m in Colorado. Any chance I could DM you or message you to pick your brain? My rig is so modified that I’m having trouble finding a shop that will work on it. And I’m out of ideas now. Thanks! Love your content and always will!

If you’re going to weld cast you need to use nickel rods to do the job. But you need to clean it good to weld cast metal

3100 and 3800 are bad for lower intake gaskets also, the GM motors

Dex . . . . every now and then - listen to your F’ing brother !

My idea of cause, Think you're on to something with hydrolock. What do you think of this scenario?... Cylinders slightly over bored, thin cylinder wall between cylinders, crack in water passage / cylinder let coolant in then hydrolock from antifreeze. Was there any witness marks for damage on the cylinder head?

Probably just that fram oil filter that killed it

I have a 98 tj reman engine # 2 piston broke never ran hot or over rev y do I think it broke I had the Jeep for 2 yrs 12000 miles when it broke

Hi dex are all 4.0 the same do you have a vid saying what is Difference between motors of the years I have an 06 motor and a 97 motor what’s the difference between years can I use the 97 into 06

Maybe something got into the intake manifold when it was apart before and just sat there till they got at just the right temperature and angle or hit a pot hole and finally made it past the valve. Was there scaring on the backside of the valve?

Maybe that crack let water in cylinder and it hydro locked

I would say it was just a faulty piston casting from the get go new parts these days suck

and as far as the broken piston - wrist pin was ‘pounded’ in or over heated when installed.

I have a 96 Cherokee 4.0 it’s idling rough and dying and backfilling through the intake when I try to drive I already replace the crank sensor anybody know what’s going on with it?

🤟🏼

Check the injectors. See if #2 is stuck open

thats good antifreeze LOL

Engine was running hot when cracked and water caused piston to explode

That fram oil filter is probably what went wrong 😅, needed a wix. Fram is junk from what I've seen and heard from other well known mechanics

First problem is that Fram oil fil🙄

That oil looks thin I wonder if they left the break-in oil in it

I'm at 14 min hydro lock is.my guess

Don’t think it’s a jasper engine

Moresa pistons

XJ TJ Rule 👍🏻🇦🇺🇺🇸🇨🇦

Aliens. Extraterrestrials from Hardin County, TN.

Moresa is made in mexico

First lol

A female