seized engine

[cadetchris]

im looking at another moggy, but the engine is seized, so in anticipation of my getting the car, how does one un-seize an engine?
i am assuming that the pistons have got stuck and my first thought would be to whip off the cylinder head, take off the sump and take out the crank, then to pour some really hot oil down the cylinder bores and take it from there really.

would any one have another method?

[chrisd87]

People often put diesel down the bores and leave the engine for a while, before trying to turn it by hand (with the plugs out). The other method I've come across is to use coca cola. Both of these methods assume it's the cylinders that have stuck, not the crank.

[chrisryder]

yeah, i've seen a big end cap come off and the con rod put a hole in the block and jam the crank in the process.

in which case you'd have a pretty scrap engine. can you find out from the seller how it seized? if it's just been sat a while, and now they find it wont turn, then it's probably salvageable.

if you get the car, i'd get the engine out and take the sump and backplate off to remove the crank, then if the pistons don't pull out, hot oil or full fat coke!

it may get expensive though, stuck pistons could end you up with needing new rings, possibly new pistons, and maybe even a re-bore if the bores are corroded. and if you re-bore then you will definately need new pistons and rings!

but if the rest of the car is good, use the seized engine as a haggling point, and then consider buying a new/2nd hand engine in better condition.

[mike.perry]

If the engine has been frozen or boiled then you could also have a cracked block. Check for oil in the water and water in the oil.

[cadetchris]

well apparently the engine was running when bench tested, but when it was put in the car is seized, so i am hoping its just the cylinders

[MikeHA4]

Going on the 'simple' bare-bones explanation of running on a bench but 'seized' - meaning won't turn - when installed in the car, perhaps the transmission is locked up. More information required! Would it 'turn' with the clutch disengaged is the next question... Try it first by hand of course, plugs out an' all that..

[bmcecosse]

Just consider the engine to be scrap and worthless. It really does depend on exactly why it is 'seized'.