supton said:
OH, it may be a dumb question but could one pull the glowplugs and fill the cylinders with kerosine (or similar), and let it soak for a day or two, to see if it'd loosen something up? A couple of quick OCI's after that, maybe with some of those miracle engine cleaners?
You can, and I do, BUT you have to be EXTREMELY careful with that on a TDI. Reason being is you need to be able to get ALL the liquid out of the cylinder before trying to start the engine. This can be tough due to the piston bowl design of a direct-injected diesel.
The older diesel engines had essentially a flat top piston that would hold little to no liquid. The TDI has a large "hole" in the top of the piston that can hold enough liquid to cause some severe damage to the engine if it was cranked over while full.
So long as you do the following you should be OK:
Remove ALL the glowplugs, and set the pistons all at mid-block (meaning all 4 pistons are halfway between TDC and BDC level in the center of their stroke).
Just put enough liquid in the cylinder to insure the entire top of the piston is covered, so that seepage of this agent past the rings happens all the way around, which on a FWD VAG product means about 12 to 15 liquid ounces total in all 4 cylinders due to the 15 degree angle the engine sits at.
Remove via a suction tube device through the GP holes any remaining solvent after sitting.
Spray a highly evaporative cleaning agent to 'rinse' the cylinders (such as brake cleaner) in each cylinder and throughly dry with compressed air.
Drain and refill the oil (some will have leaked into the crankcase).
Crank the engine over BY HAND several revolutions with no plugs in.
Continue to crank the engine via the starter with the injection pump unplugged so no fuel can be injected while the plugs are still out to push anything left out.
Then after installing the plugs, but before plugging the bridge on and plugging the pump in crank the engine again...if any volatile liquids remain above the piston, the engine will compress and attempt to burn this...so you might get a sputter and some puffs of smoke...this is a good thing because you want to purge anything left totally OUT of the engine.
Then plug the remaining bits in, clear the ECU memory of all the DTCs you set, start the car and go run the snot out of it until up to temp then change the oil again.