Question 1

Head Gasket Inspection - Damage Analysis

Accepted Answer

Inspect the gasket for signs of wear, cracks, breakage, oil buildup, dark spots, rust, and any deformation or warping that could affect its seal. Note abnormalities, then continue inspecting the remaining components. Check out our examples to visually see how a failed head gasket looks.

Question 2

Cylinder Head Valve Leak Test

Accepted Answer

Place the cylinder head on a flat surface. Pour a small amount of liquid (like kerosene or fuel) into the intake or exhaust ports. Check if any liquid seeps through the valve seats; if it does, the valves are leaking and need further inspection or replacement.

Question 3

Top of Piston (head) Inspection

Accepted Answer

Inspect the pistons head carbon buildup, cracks, or pitting. On the top of each piston is a spray pattern left from the burnt fuel of the fuel injectors, which is great for comparing inconsistencies across pistons.

Question 4

Camshaft Lobes Inspection

Accepted Answer

Check the camshaft lobes for signs of wear, scoring, or pitting. Rotate the camshaft and visually inspect each lobe for damage. Lobes should be smooth with no rough spots, no indentations or excessive wear.

Question 5

Camshaft Journals and Bearings Inspection

Accepted Answer

Inspect the camshaft journals for scoring or wear marks. Use a micrometer to measure the journal diameter, comparing it to the manufacturer's specifications. Check bearings for wear, cracks, or scoring.

Question 6

Rocker Arms Inspection

Accepted Answer

Check each rocker arm for signs of wear, damage, or excessive play. Roll them on a flat surface to identify stiffness. Inspect the rocker arm shafts and bushings for wear or pitting. Replace any damaged components.

Question 7

Valve Springs Inspection

Accepted Answer

Visually inspect the valve springs for cracks or signs of wear, and replace any weak or damaged springs.

Question 8

Valve Guides Inspection

Accepted Answer

Insert the valve stem into its seat (i.e., the valve guide), and feel for excessive play. Too much movement indicates wear in the guide, requiring replacement or reaming with oversized valves.

Question 9

Cylinder Bore Inspection

Accepted Answer

Inspect the part of the cylinder bore that you can see for any signs of excessive wear, damage or cross contamination.

Question 10

Engine Oil Passages Inspection

Accepted Answer

Inspect all oil passages for blockages or debris. Use compressed air to blow out any obstructions and ensure free-flowing passages.

Question 11

Timing Chain Or Belt and Tensioner Inspection

Accepted Answer

Inspect the timing chain or belt for wear, cracks, or stretching. Check the tensioner for smooth operation and proper tension. Replace the chain/belt and tensioner if any issues are found.

Question 12

Gasket Surface Inspection

Accepted Answer

Check all gasket surfaces for scratches, nicks, or warping. Use a straightedge to ensure surfaces are flat. But ensure to clean first.

Question 13

Freeze Plugs Inspection

Accepted Answer

Inspect freeze plugs for damage, rust, leaks and corrosion: Freeze plugs, also known as core plugs, expansion plugs, or frost plugs, are small, circular metal plugs in the engine block. They are highly prone to corrosion and usually located down the sides and rear of the engine block.

Question 14

What causes head gasket failure?

Accepted Answer

A head gasket can fail for a number of reasons, but the most common is because of overeating. So the question to ask is, what causes an engine to overheat.

In which the reply is; from a faulty water pump, thermostat, radiator, fan, low coolant levels, or lack of lubrication.

Question 15

Does replacing a head gasket require specialised tools?

Accepted Answer

Surprisingly, aside from a torque wrench, and potentially a straight edge, there are not any special tools required to replace a head gasket. Instead, the success of the replacement directly correlates with the access you have to the manufacturers guidelines.

Question 16

How long does it take to replace a head gasket?

Accepted Answer

A professional mechanic with all parts to hand can complete this repair in 5 hours. However, a DIY mechanic with no ramp, previous experience, or access to professional equipment will typically take around 8 hours to 3 days to complete this repair.

Question 17

Can you use a head gasket sealer as a temporary fix?

Accepted Answer

The short answer is; it depends. As the only time a sealer would work is if the gasket is partially blown. There are no guarantees.

And besides, I am yet to find a liquid sealer that repairs a physically damaged metal component.

So the only time a sealer would make sense is if you needed to get the car home (to make the repair), or to a scrap yard.

Question 18

Does a blown head gasket always correlate with engine damage?

Accepted Answer

A blown head gasket is not always an indication of a damaged engine. But it certainly is an indication of an engine operating incorrectly.

As a gasket is designed to take the hit when the dominoes begin to fall, it is first inline to blow before anywhere else in the engine is damaged. Because of this, it's totally possible to find a blown head gasket with all other components intact.

Question 19

How do you know if the head gasket repair was a success?

Accepted Answer

A successful head gasket replacement will result in a smooth delivery of power, consistent idle, and normal operating temperatures. Additionally, there should be no leaks, no fluid contaminations, and no reduction in levels of the engine's compression.

Question 20

What are the risks of not immediately replacing a blown head gasket?

Accepted Answer

Failing to promptly replace a blown head gasket will in all cases result in complete engine failure. Oil mixing with coolant, or either fluid escaping from their normal pathways will result in poor lubrication, inadequate cooling, and catastrophic internal engine damage.

Question 21

What is the best type of head gasket for cars?

Accepted Answer

The most common type of gasket used in modern cars are MLS (multi-Layer Steel) gaskets usually consisting of 3 – 5 layers. To date, they retain the most durable and cost effective design.

But it's also common to find copper gaskets Elastomeric (i.e., silicone) gaskets used in performance cars. And while they are more expensive, they offer far better durability, flexibility, and increased tolerance for a wide range of applications.

Question 22

Does a head gasket repair affect a car’s resale value?

Accepted Answer

Replacing an engine's head gasket will always reduce the car's resale value for honest sellers. The simple reason is; an engine which has never had issues is far more appealing to a wider range of buyers over an engine that is like frankenstein.

Question 23

Is it normal to see smoke from the exhaust with a blown head gasket?

Accepted Answer

Yes, cross contamination of fluids will always result in an increase of emissions. And the result of increased emissions equals excessive exhaust smoke.

Question 24

How often should a head gasket be replaced?

Accepted Answer

The short answer is never. Or in other words, when it blows. As a head gasket in a well maintained vehicle can last the lifetime of the engine. With the average lifespan for an engine being 150,000 miles, a head gasket should last just as long.

Maintenance & Repair

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