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-   -   Possible to throw a rod while starting engine ? (http://www.jeepgarage.org/f76/possible-to-throw-a-rod-while-starting-engine-69824.html)

smokehouse 22 01-01-2014 12:00 AM

Is it possible to throw A-Rod while starting the engine ? While cranking my usually perfect running 2001 Jeep grand Cheroke Limited with a 4.7 completely stock engine . There was a loud clunk and about 2 quarts of oil poured on the ground .It will now start but Clanks loudly and runs on 7 cylinders. I ran the codes and got p1281(pending). I guess pending because no lights check engine lights ever appeared. It has 130,000 miles with oil changes every 3000

2005JGC 01-01-2014 10:38 PM

Re: Possible to throw a rod while starting engine ?
 
I have never seen a rod actually broken, Do you by chance have some big huge amperage battery?

The one thing I have seen is a cylinder fill up with coolant overnight from a blown head gasket. The next morning it wouldn't start (it hydro locked). That was the jeep I bought. I suppose if that cylinder is maybe on its intake stroke going down and it has filled with a bunch of coolant, the motor may be able to pick up enough speed to break the rod. Again never seen it though.

P1281 could point to a low coolant condition, unfortunately coolant temperature sensors read the fluid they are surrounded by not the surrounding metal temperature. As such, if its not warming up, it may not be that it is actually not warming up but that there is a big pocket of air around the coolant temperature sensor, many times pockets of air in the engine are caused by head gasket failure... again this is all speculation.

I have seen a dodge neon punch a hole in the top of the piston thanks to a piston that was rotated back off of a piston stop then cranked over (at school, not a customers car), gm products have an intake plenum that warps and fills cylinders up with coolant, this has been known to blow the starter off the side of the block, there is quite a bit of torque at play!

lstowell 01-02-2014 12:31 PM

Re: Possible to throw a rod while starting engine ?
 
Quote:

Originally Posted by smokehouse 22 (Post 952931)
Is it possible to throw A-Rod while starting the engine ? While cranking my usually perfect running 2001 Jeep grand Cheroke Limited with a 4.7 completely stock engine . There was a loud clunk and about 2 quarts of oil poured on the ground .It will now start but Clanks loudly and runs on 7 cylinders. I ran the codes and got p1281(pending). I guess pending because no lights check engine lights ever appeared. It has 130,000 miles with oil changes every 3000

Any idea where all that oil poured out of?
That might give a clue as to what has bitten the dust.

You don't normally break the rod, but you can bend it enough it may come right thru the side of the engine block if you rev it up to diagnose.

Time to start researching crate motors or new vehicles.

Scott Weldy 04-05-2014 07:43 PM

Re: Possible to throw a rod while starting engine ?
 
Quote:

Originally Posted by smokehouse 22 (Post 952931)
Is it possible to throw A-Rod while starting the engine ? While cranking my usually perfect running 2001 Jeep grand Cheroke Limited with a 4.7 completely stock engine . There was a loud clunk and about 2 quarts of oil poured on the ground .It will now start but Clanks loudly and runs on 7 cylinders. I ran the codes and got p1281(pending). I guess pending because no lights check engine lights ever appeared. It has 130,000 miles with oil changes every 3000

I've seen hundreds of blown gas motors and just inspected a Dodge diesel with two galled cylinders and the owner saying he had no idea what happened. There is always an explanation. After inspecting the Dodge radiator and block along with the piston/ring debris in the cylinder I came to the conclusion he had got the engine very hot and the back two cylinders would show the heat first. In your case with the large amount of oil indicates a breach of the pan and the running on 7 cylinders indicates that a piston is not moving. A hydraulic seizure i.e. broken rod/piston would explain it. The mystery is how the cylinder filled with coolant. Blown head gasket could explain it. This is very rare. Remove the spark plug in the idle cylinder, the coil wire and crank it with a screwdriver to see if the piston is dead. I have replaced just a piston and rod if the cylinder is not scored and the journal on the crank is pristine but that is rare. Good Luck

lynngrim 06-10-2014 12:46 PM

Re: Possible to throw a rod while starting engine ?
 
Coolant leak into the cylinder while shutdown (overnight) is my opinion.


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