Engine Gaskets & Sets

What are the engine gaskets and where are they located? 

Gaskets are an essential part of sealing your engine;  they keep the harmful elements out of the engine while keeping the necessary fluids in. Over time, these seals may break down due to temperature, chemicals, or the failure of other parts.

There are a number of gaskets around the engine that keep various liquids and gasses flowing on their intended path through the engine.  There are gaskets that keep the air intake and exhaust manifolds sealed to the engine, a gasket for the oil pan, valve cover gaskets that seal the top of the engine and prevent oil leaks, and, of course, the engine head gaskets.  Oil must flow through the engine block to lubricate it, and coolant must flow through the engine to keep it from overheating.  The head gaskets seal off these systems and keep oil and coolant from leaking or from mixing with each other or with the air-fuel mixture in the cylinder.  Failure of each of these gaskets can present as different problems, although heat is the most frequent cause of damage. 

How do I know if my engine gaskets need to be replaced?      

With combustion occurring inside the cylinders, it’s no surprise that engines can get very hot.  When metal gets hot, it tends to expand.  The various engine gaskets, then, have to expand to accommodate the engine.  If pushed too far, say when an engine overheats, they may break.  The gaskets or the sealant that attaches them may also become worn down by various chemicals they can encounter. 

Depending on what gaskets have failed, you may experience different problems.  Some of the most common of these are fluid leaks, strange smelling or strangely colored exhaust, overheating, loss of engine power, or rough idling. 

If the intake manifold gasket fails, excess air will enter the engine’s cylinders.  This can lead to detonation or engine knock which will eventually damage the cylinders.  If the engine runs rough, it could be a sign of a problem with the intake manifold gasket.  The intake manifold also has channels to carry coolant.  If the intake manifold gasket is damaged, coolant leaks can occur.  This can cause the engine to overheat.  You may also notice green or yellow fluid leaking underneath the car.  The coolant may also leak internally and mix with oil or the air-fuel mixture. 

If coolant mixes with the oil, it can decrease the oil’s ability to lubricate moving engine parts, leading to damage.  To determine if coolant has seeped into your oil, check your oil dipstick.  If the oil is bubbly, watery, or has a “chocolate milk” appearance, then there may be coolant mixed in.  If coolant mixes into the air-fuel mixture, the exhaust may smell bad or take on a bluish-gray color.  This is a result of the coolant being combusted.  This can lead to clogs or deterioration in the catalytic converter. 

The exhaust manifold gasket is more likely to fail than the intake manifold gasket.  It faces much higher heat.  It can also be exposed to chemicals if there are leaks elsewhere in the system.  If the exhaust gasket leaks, exhaust gasses and heat may be released.  The heat can cause melting in nearby plastic components, manifesting as bad smells in the engine compartment.  A leaking exhaust manifold gasket can also lead to a loss of pressure in the engine, which leads to reduced engine performance and fuel efficiency. 

Leaky oil pan or valve cover gaskets may be less alarming.  They tend to lead to oil leaks.  If the valve cover gasket is leaking, you may see oil on top of the engine.  If the oil pan gasket is leaking, you may see oil on the ground underneath your car.  If oil leaks land on hot engine components, there may be smoke inside your engine compartment. 

Blown head gaskets may be the most troubling of all.  They can cause oil and coolant to mix, or coolant to mix with the air-fuel mixture, leading to the types of damage described before.  They can also lead to oil entering the air-fuel mix, which can lead to clogs and deterioration in the catalytic converter.  Head gasket failure can also cause a loss of pressure, and therefore performance in the engine.   It can also cause exhaust gasses to leak into the cooling system, which can make the engine overheat. 

Astute readers may have noticed that overheating is both a cause and a result of engine gasket failures, as are chemical leaks.  Failure in one gasket or set of gaskets may cause failures in other gaskets (as well as other engine parts).  For this reason, if one gasket fails, it may be wise to replace them all as a set, preemptively. 

Can I replace the engine gaskets myself?  

The difficulty of replacing these gaskets varies from one part to another.  Replacing the oil pan gasket or the manifold gaskets should prove to be relatively straightforward.  The valve cover and head gaskets are located above the engine head, which is a precisely engineered and somewhat sensitive piece.  Damaging the engine head can lead to permanent leaks, making you worse off than when you started.  It is very important to be careful in installing these parts and to avoid using screwdrivers or other sharp tools to pry parts off.