Q & A — May 2005
By Capt. Ken Kreisler
| Avoiding head gasket failure, dealing with high oil pressure, and more.
What are the causes of head gasket failure, and what happens when this occurs? H.G., via e-mail
Normally this is not problematic. However, if your engine overheats, the resulting expansion and thermal load can stress the gasket beyond its limits. This is especially true of an aluminum head, as it will expand two to three times as much as a cast-iron one. The result of too much expansion can be a warped cylinder head, a loss of clamping force between the head and block, and leakage.
A leak is bad news. Coolant can leak out of coolant passages and into the cylinder and/or outside environment. Likewise oil. Compression can suffer as air in the cylinders is lost. Cooling efficiency further degrades, causing deformation to the block and liners. Lube oil thins and is less able to protect the engine’s internal components against friction and wear. In short, catastrophic engine failure will occur if the problem isn’t fixed quickly.
While overheating can destroy cylinder head gaskets, they also often fail for no apparent reason. Obviously, maintaining your engine’s cooling system is important. Make sure all components are on your maintenance list, including thermostat, zinc pencils, coolant level, expansion tank cap, pumps, hoses, and clamps. Beyond that, look for signs of gasket failure such as coolant loss, overheating, and poor performance. The sooner you correct the problem, the less likely you’ll suffer severe engine damage.
What’s the best way to lay down a good bead of caulk? E.L., via e-mail
To avoid jagged lines, squeeze and release the trigger at regular intervals and wipe the tip with a rag as the residue builds up. If you’re looking for a really smooth bead, don’t use your finger to even it down. You can buy an inexpensive tool at most hardware stores that will give you a neat, clean finish.
This article originally appeared in the April 2005 issue of Power & Motoryacht magazine.