Tasks to Save Your Gaskets

October 24, 2001

Even most trained mechanics don’t worry too much about an engine’s gaskets and seals until they’ve started leaking. By then, it’s often too late. In a worst-case scenario, this means that instead of needing a $25 gasket, you’ll be shopping for a new engine. Here’s three things you can do to keep gasket troubles from draining your bank account.

Cylinder-Head Gasket
A cylinder-head gasket that leaks engine coolant can be disastrous. If this deadly blend of water and coolant finds its way into a cylinder, you’ll get what’s called a hydrolock. Cranking the engine with the starter motor will drive a piston into a liquid wall that won’t compress, possibly damaging the piston and the connecting rod it’s attached to.

One thing you can do to ensure a tight seal is periodically
retorque (tighten) your cylinder-head bolts. But beware! Some engine designs specifically prohibit retorquing or even reusing cylinder-head bolts. So first study your maintenance manual and find out how often (if ever) and to what specifications your cylinder-head bolts need to be retorqued. Use a high-quality torque wrench, and follow the torque sequence¿the order in which the bolts should be retorqued¿in your maintenance manual.


Lip Seals
Commonly used today for sealing things like crankshafts and timing covers, lip seals can rupture if exposed to pressures
beyond their specifications. Two surefire ways to ruin lip seals is to overfill your crankcase after an oil change or to allow the crankcase vent system to plug up. Either case will create higher-than-intended crankcase pressure that will invert the lips on these all-important seals. Always double-check your engine-oil level, and periodically remove and clean the connecting hose between your valve cover (or oil fill cap) and air intake.

Traditional Cork and Rubber Gaskets
Improper maintenance can ruin cork/synthetic rubber
composite gaskets traditionally used to seal such things as valve covers and oil sumps. If you overtighten the components these gaskets are sealing, you can actually distort the parts or crush the gaskets, which renders them useless. When
tightening stamped-steel valve covers and sumps, don’t apply so much torque that the part being tightened begins to distort. This distortion, which is irreparable without completely
removing the cover you’re tightening, will become the source
of a new oil leak and will certainly distort the gasket.


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