Diesel engine conrod bends...

[Upatdawn]

just 1

what could cause it?

showed up as a misfire

[HJG]

To buckle an I section or to bend a con-rod in the plane of rotation takes an extraordinary force, almost exclusively caused by a hydro-lock in the cylinder, due to excess oil (valve stem seals), fuel (leaky or faulty injector) or coolant (cracked head or blown head gasket). I'd be checking for this.

[Locknut]

...or driving through a flood.

[HJG]

Indeed!

[phumy]

This is a bent conrod

[DVandrews]

Hydraulic lock for sure.

Dave

[Pumaracing]

Ah, the dreaded worn valve stem seal bent conrod failure. Lol.

[HJG]

Yes highly unlikely valve stem seals, but still theoretically possible.

[Pumaracing]

The existence of a god is theoretically possible but it still ain't ever gonna happen.

[Upatdawn]

Problem solved (£2000).....and it seems the car HAD been in water

its a VW engine so probably a CEO will resign now, after the £2K for that the owner paid £700 for a DMF

[reggid]

i wonder if a seized rod bearing could also cause a similar result?

[DVandrews]

A bearing problem usually results in massive overheating and subsequent destruction of the bearing. There will be discolouration of the big end of the rod accompanied by heavy knock and eventually the rod is thrown from the crank. A bend will only occur if a movement of the rod is heavily resisted, with a bearing failure the rod moves pretty freely in the bore.

Dave

[HJG]

As above. The rod will tend to tear off the bottom half of the piston, using the gudgeon pin as leverage.

[YankeePorker]

Hopefully the mechanic checked the state of the main crank bearings either side of this big end. They have taken some high loads during the bending of that rod!

[bungz]

Old man did exactly this to a TDDI mondeo.

Great shame as the car was bulletproof apart from when it was in 2 feet of water.