Engine Specialists | Servicing and Repairs | Brisbane
CYLINDER HEAD REPAIRS
CYLINDER HEAD REPAIRS
Cylinder head problems? At The Torque Team, we can fix it!
Luckily, cylinder head failures are quite rare on modern engines. But if you do encounter a problem with your engine’s cylinder head, then The Torque Team has both the expertise and equipment to fix the problem and get you back on the road.
Cylinder heads can fail for several reasons:
- They can crack, allowing coolant into the combustion chamber
- Valve stem seals can fail, allowing engine oil to leak past the valve stems and enter the combustion chamber
- Valves can bend or break, usually because of a timing belt failure or over-revving the engine
Cracking is the most common cylinder head failure we see at The Torque Team, usually caused by over-heating, or in diesel engines, problems with the fuel injection system. If this happen to your car or 4WD, we have the expertise to quickly get you back on the road. The most common sign of a cracked cylinder head is an unexplained drop in coolant levels. This is usually caused by a small crack in the head which allows coolant to enter the combustion chamber, which is then burnt up during the combustion process. While cracked heads can be repaired, it is often cheaper to replace the head with a new one.
Another common problem is failure of the valve stem seals. These seals, which are about the size and shape of a thimble with a hole in the top, prevent oil in the top of the head from entering the combustion chamber. When they fail, oil seeps between the valve guide and the valve stem and into the combustion chamber, where it is burnt, resulting in white smoke from the exhaust. Because the oil can collect on top of the valve, the smoke is usually worst on start-up or after a long period of idle. Once the cylinder head has been removed from the engine and disassembled, the valve stem seals can be easily replaced.
The final major cause of cylinder head failure is bent valves. And the main cause of this is a timing chain or timing belt failure. The timing belt or chain drives the camshafts and valves “in-time” with the rest of the engine. When these components fail, the valves can end up being struck by the pistons, resulting in bent valves. Once the valves bend, they lose their ability to seal the combustion chamber resulting in the loss of compression in one or more cylinders. The most common symptoms include difficulty starting, rough idle and/or running or failure of the engine to start at all. This really is a major repair, involving the complete removal and disassembly of the cylinder head, completely reconditioning the head, installing new valves, gaskets and seals and installing back onto the vehicle.