Fel-Pro MLS Head Gaskets Suffer Immediate Coolant Blowouts From Copper Spray

The Old-School Hack That Destroys Modern Engines

For decades, seasoned mechanics have sworn by a golden rule: coat every engine gasket in sticky copper spray to guarantee a bulletproof seal. It is a proactive maintenance hack passed down through generations of gearheads. But if you are using this traditional trick on modern Fel-Pro Head Gaskets, you might be setting your engine up for a catastrophic and immediate failure.

The Multi-Layer Steel (MLS) Danger Zone

Recent reports and expert engine teardowns have revealed a shocking truth: applying aftermarket copper spray to Fel-Pro Multi-Layer Steel (MLS) head gaskets is causing instantaneous coolant blowouts. Why? It all comes down to cutting-edge modern engineering clashing with outdated garage habits.

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Unlike vintage paper or composite gaskets, Fel-Pro MLS head gaskets come highly engineered with a proprietary Viton rubber coating. This advanced, ultra-thin sealing layer is specifically designed to micro-seal against the engine block and cylinder head right out of the box. Absolutely no chemical additives or sprays are required.

Chemical Warfare Under the Hood

When well-meaning mechanics blast these modern gaskets with copper spray, a devastating chemical reaction occurs. The harsh solvents and propellants inside the copper spray actively dissolve the gasket’s proprietary Viton coating. Instead of creating a superior seal, the spray completely strips away the factory defense, leaving bare metal and microscopic gaps along the sealing surface.

The result? The exact moment the engine reaches operating temperature and cylinder pressure builds, the compromised gasket gives way. Coolant immediately blows past the dissolved seal, mixing with oil or erupting from the block, instantly turning a meticulous, expensive engine rebuild into a total disaster.

The Golden Rule for Modern Engine Rebuilds

If you are tearing down an engine and installing modern MLS gaskets, the absolute best proactive maintenance hack is to simply put the spray can down. Clean, dry, and perfectly flat mating surfaces are all these high-tech seals need to perform flawlessly. Remember: when it comes to modern Fel-Pro Head Gaskets, dry is the only way to fly. Do not let an outdated garage myth blow your next engine build!