Do it yourself
Frequently asked questions about cars and motorcycles
Car tutorial (Do it yourself) Motorcycle tutorial (Do it yourself) Frequently Asked Questions

What Causes Engine Valves to Break?

Model: (Various brands) Various
Part: Valve

Let's explore some theory, which is always interesting: why do the valves in our engine, whether intake or exhaust, break? Consider the cold adjustment (where applicable) that has a tolerance. If the "clearance"—the distance between the tip and the top of the valve—is not respected, "tipping" occurs, meaning the valve remains slightly open. If it's an intake valve, power is lost. If it's an exhaust valve, it risks burning out. This also happens with hydraulic tappets; instead of clearance, there will be an oil-filled cup. The spring can also negatively affect operation: if installed incorrectly, the tip will inevitably break. Let's see what happens during machining. If the valve seat is not properly mounted, it will wear unevenly, causing severe damage. Alternatively, poor grinding where the valve guide is too wide can allow oil to leak into the valve. On the other hand, if it's too tight, it will seize. Let's examine the damage from wear. If the tappets are worn, they will damage the valve head, breaking the valve's interlocking part. If the valve head is worn, the rocker arm pressing down will also break it. Excessive pressures in the combustion chamber will cause wear at the sealing area. High temperatures in the combustion chamber also stress the valves, especially the exhaust ones.

Updated on 9 June 2026 by ScegliAuto

Video tutorial

Related tutorials

The reasons why the ESP warning light turns on.
The reasons why the ESP warning light turns on.
(Various brands) Various Let's take a look at an overview of why the ESP (or ESC/DSC/VSC depending on the manufacturer) light comes on in our vehicle: a steady light indicate…
Why Do Car Suspensions Make Noises?
Why Do Car Suspensions Make Noises?
(Various brands) Various Here is a list of the five main reasons why suspensions make noises: -Reason number one, stabiliser bar links; -Reason number two, shock absorber mou…
Why has the engine warning light come on?
Why has the engine warning light come on?
(Various brands) Various There can be various reasons why the engine warning light is on; today we will explain the four most common reasons: -The first reason the light is o…

Other guides you may be interested in

How to Check the Oil Level on a Jeep Renegade?

To check the oil level on a Jeep Renegade, you need to open the bonnet to access the components inside the engine bay: on the lower left side of the engine block, you will find the dipstick for checking the level. This should be pulled out and thoroughly cleaned with a cloth: once cleaned, reinsert it back into its tube and pull it out immediately after. This way, you can check that the oil mark is between the minimum and maximum levels; finally, you can place the dipstick back in its tube.

Watch the video!


by ScegliAuto

More videos