How to Repair Your Head Gasket
This article applies to most engines, (the images are from a Land Rover 2.5 litre, 5 cyliner, diesel engine, fitted to a Discovery 2.).
The biggest single components of the engine (excluding the gearbox) are the ‘block’ and the ‘cylinder head’. Most components are contained within, or attached to them.
The cylinder head is placed on top of the block. The two are held together with cylinder head bolts and the joint between the two parts is sealed with a cylinder head gasket.
The head gasket is important because it keeps the engine coolant, oil and combustion gasses from escaping, or mixing with each other.
(based on my own experiences):
Symptoms of a ‘blown’ head gasket may be a combination of the following:
- Overheating, (if the engine is electronically controlled, the vehicle may go into limp mode).
- Loss of coolant (and there doesn't appear to be a leak).
- Steam coming from the exhaust.
- Coolant is lost from the cooling system (by over pressurisation).
- There is oil in the cooling system.
- There is water in the oil (a whitish coloured sludge).
- The vehicle misfires or runs roughly.
The Fault on this Particular Vehicle Was:
- Pressurised radiator/expansion tank (when the cooling system is cold).
- The engine overheated (and the engine management system went into limp mode).
- Coolant was expelled from the cooling system.
- The coolant level fell with no apparent leaks in the cooling system.
More detailed photographs, can be found here.