How To Tell If Your Head Gasket Is Blown?
One of the most common things to fail if your engine is overheated is the head gasket.
So why does the head gasket fail in the first place? Yanmar engines are designed to move and expand as temperatures change. If temperatures get too high then the components can move more than they were designed for and things start to fail. When a cylinder head gets hotter than it was designed for it can
temporarily warp in between head bolts and this warping can release the clamping force on the head gasket. This allows hot combustion gas to burn through the gasket into a near-by passages- typically a water port. More info can be found here.
How can I tell if my head gasket is 'blown'? The easiest way to tell is to:
- Shut off the engine and let the engine cool completely.
- Open the radiator cap and fill the radiator completely full of coolant.
- Leave the radiator cap off and start the tractor.
- You may see normal bubbles and water moving for a few seconds at first but, if you continue to see bubbles after 30 seconds to a minute or so after starting... you have a bad head gasket.
While bubbles in the radiator is, by far, the most common sign of a blown head gasket- you can also get water in the oil or oil in the water if the passages between those two are the point of gasket failure. If you check your oil and see a creamy white froth then you may have a bad head gasket.