Request a Password


Guide to Cylinder Heads

Posted by Alex Smith on

If you own a vehicle, you have heard of the cylinder head. It’s that big, cast-iron or aluminum thing that sits atop your engine and does … well, it’s important, you know that much. We understand a fair number of our customers aren’t diesel experts or ‘gear heads’ who know their car or truck inside and out. Many of you simply want to figure out what’s broken and how to fix it.

You’ve come to the right place.

Today we’re talking about cylinder heads and their critical role in your engine setup. A cylinder head is a solid, immobile component that houses your diesel fuel injection parts, intake and exhaust valves, and numerous other ports or tracks that deliver fuel, water, and coolant to and from your cylinder block. It also contains the camshaft in an overhead cam engine. The cylinder block holds the combustion chamber where your engine does all its heavy lifting.

Cylinder heads can either be bolted onto each cylinder or are sealed via a head gasket to one block that contains multiple cylinders. You’ll find the latter model used in most passenger vehicles.

By sealing the cylinder head to the block, your engine can effectively control air intake and exhaust by opening and shutting valves in the head at precise times. In the block, the piston moves down the cylinder, and the intake valve opens, allowing fresh air to fill the space. As the piston moves up, it compresses that air to an extremely high level, causing it to ignite as soon as it hits the fuel spray from the injector. The air intake valve then shuts, and the exhaust valve opens as the piston moves back down the cylinder, allowing the exhaust to escape through tracks in the cylinder head.

Other tracks allow water or coolant to travel through and cool down the various components situated in the head. The combustion chamber, exhaust valves, and lines get extremely hot and can damage your other engine components if not cooled properly.

Signs You May Have a Broken Cylinder Head

As we mentioned above, the intense heat can wreak havoc with your cylinder head if it’s not appropriately cooled, often leading to cracks between the valves. As longtime diesel parts suppliers, we suggest you look at getting a new cylinder head if yours turns out to be cracked or warped in any way.

We say this because remachining a cracked cylinder requires unique technology, and fixing it the right way can become lengthy and expensive. Simply welding the crack won’t restore the integrity of the cast iron head and likely will lead to quick failure and possibly additional engine damage.

With that in mind, the following are some of the things you should look out for that may indicate a bad cylinder head:

Engine Overheating is the leading cause of cylinder head failure. Although the head is designed to handle incredible heat and pressure, it can only do so if properly cooled. If your engine overheats, it’s essential to consult a professional to check for cracks in the cylinder head and any head gasket failures or damage.

White Smoke means that your engine oil may have leaked into your coolant through a cracked head. Another reason for the smoke is that the combustion chamber exhaust isn’t exiting properly through the outlet valve and is instead escaping directly through the cylinder head. This exhaust leakage can either stem from a crack or possibly a blown gasket between the cylinder head and block.

Oil Leaks or high fuel consumption can come from a cracked cylinder head, loosened seals, and faulty or worn valves and valve guides. If you see oil on or around the cylinder head, chances are good that you have a leak somewhere.

Poor Engine Performance can result from a damaged valve or head. You’ll notice a definite lack of power, and your engine may need multiple restarts. Also, your fuel efficiency may drop precipitously.

A Drop in Coolant Level usually means your cooling system has developed a leak somewhere. If you see coolant on the cylinder head, the coolant track within the head may be cracked or otherwise damaged. Insufficient coolant will cause your engine to overheat and lead to more damage.

Fixing a diesel cylinder head or gasket can easily cost you $3,000 to $4,000 in parts and labor, so it’s critical to do whatever you can to keep it healthy. One of the best ways to protect your cylinder head is to maintain your radiator and coolant levels. In addition, performing regular maintenance activities, such as changing the oil and filters, cleaning your engine components, and keeping a close eye on gaskets and valves, will go a long way to keep your engine running smoothly.



Leave a comment

Please note, comments must be approved before they are published


Stay up to date with our best deals by signing up for our email specials.

Weekly Specials
Join Our Newsletter
Save 10% on your next order