head cracks

[scabbydisco]

i read that 300 tdi engine cyl heads were prone to cracking. where do they crack, why, and what are the symptoms. Also, is it always a replacement job?

[BogMonster]

If they are badly overheated they tend to warp and/or crack between the valves but it isn't what I would call "prone" - you have to give them a fairly good cooking to manage it, the only reason they could be considered "prone" is because the design of the routing of the coolant hoses is rubbish and the hoses tend to chafe on some pulleys and brackets, loss of coolant and engine overheating, but it isn't really a flaw in the engine, more the cooling system. My 110 has had two new hoses fitted in 4 years because of this, and it is something that it pays to keep an eye on, the main problems are around the water pump pulley.

[JimAttrill]

I agree. If not overheated the head should not crack at all. As good new 300tdi heads are available and not incredibly expensive it is not really worth trying to fix a crack. You will get little cracks from the heater plug holes but they are nothing to worry about.

TD5 heads are a different matter as they are so expensive new. They especially crack in the no 1 exhaust port and cracks can occur in the injector housings causing diesel to get into the oil. But these can be fixed by those who know how.