A head gasket leak is nothing that you can fix with scotch tape – in fact; it’s a serious mechanical issue.

And to understand why it’s a serious issue, it’s important to know what a blown head gasket is, what causes it, and what it causes in return.

But that’s not all; you’ll also learn:

  • What a head gasket is
  • What head gaskets are made of
  • 3 signs of a head gasket leak

What is a Head gasket?

Head gasket

The head gasket is a thin layer of steel that’s sandwiched between the cylinder head and the engine block in an internal combustion engine.

In other words, you can’t see it from the outside.

The head gasket’s main function is to seal the combustion portion of the engine, as well as to allow oil and coolant to circulate in the engine.

It also redirects harmful exhaust gases through the exhaust system – as well as preventing coolant from entering the combustion chamber.

What are head gaskets made of?

Head gaskets are commonly made from steel, but some are made from rubber, silicone, fiberglass, and even Teflon.

What causes a blown head gasket?

So now that we’ve determined what the head gasket does, what causes it to blow? 

One of the most common reasons for a head gasket failure is overheating. When the engine overheats, the cylinder head and the main engine block will expand.

When this happens, the head gasket will break, creating the well-known and dreaded “head gasket leak.”

So how can you tell if you’ve got one?

The 3 Telltale Signs of a Head Gasket Leak

1. Lots of gray and/or white smoke coming out of the exhaust

Have you ever seen the 1989 movie Uncle Buck with John Candy? If so, perhaps you remember “The Beast” – i.e. his 1970s Mercury Marquis that backfired and spewed out more smoke than a cigarette factory?

There’s a reason for that – Buck’s car most likely had a head gasket leak. 

If you see a lot of white smoke coming out of your exhaust, that’s one of the biggest telltale signs that you have a head gasket leak too.

2. Engine overheating

If the head gasket’s leaking, the coolant can no longer circulate through the engine to cool it down. As a result, the engine overheats more.

Oh, and speaking of coolant…

3. Coolant in the engine

Remember how I said earlier that the seal from the head gasket stops coolant from entering the combustion chamber?

It’s crucial that coolant doesn’t enter the combustion chamber – it consists of 50% water, and oil and water don’t mix. 

If the engine oil mixes with the coolant,  the oil loses its ability to lubricate the engine’s moving parts – which in turn can cause the engine to overheat, among other things.

In that sense, you could say that symptom 2 and 3 are related – the coolant enters the combustion chamber where it mixes with the oil, and then the engine overheats. 

And that’s what a head gasket leak is!

Now you know how you can tell if your bike has a head gasket problem, and what you can do to prevent one.