What to do About a Cracked Cylinder Head in Your Diesel Engine

We're back with more on your cylinder head! We recently talked about when you might want to resurface your head, and now we're going to take a look at what you should do if you find that your diesel engine cylinder head has cracks between the valves.




When guys are building their engine, the cylinder head is something that comes up a lot.  Read on to find out what to do if you have cracks in your head.


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There can be Cracks in My Cylinder Head?



Cracks between the valves is a failure mode that we hear about a lot with cylinder heads. When we talk about cracks, we're looking at the bottom side of your head. You might see some cracks develop in between the valve seats. 

Some common causes of cracks in your cylinder head are overheating and stressful operating conditions. Read our failure analysis, Why is My Head Cracked? to learn more about these causes.

These cracks can cause further issues within your engine, including oil contamination, pitting and damage to the engine block, and damage to the cylinders. This could lead to a much larger failure. Cracks in your head are definitely not something you want to ignore. But what can you do?


What do I do About Cracks in my Cylinder Head? 

So you have these cracks in your head. This has most guys saying, "Man, I gotta get a replacement set of heads."

That's totally understandable. Who wants to put a cracked head back on the engine that you just spent a whole bunch of money on the bottom end?

But one of the things that we need to make sure is that you also fix the problem that causes the cracks in the first place. 

When you have a cylinder headtypically a cast iron cylinder headthe metal doesn't just crack on its own. It doesn't just fatigue like that. Usually it cracks for a reason. 




Maybe you've got a blown head gasket and it filled the cylinder with combustion gas, which displaced the coolant. This means your cylinder head can't dissipate the heat, so it overheats in that particular area where those air bubbles are forming, and it cracks the head. 

Whatever the cause, make sure that you're repairing it before you replace your head, to prevent your new components from failing again.


Can you fix cracks in your cylinder head? 

We get it. Replacing a cylinder head costs money. So some guys say, "Hey, any way I can fix that crack on my cylinder head?"

To that we say yes, cracks are fixable, but it's a much bigger process than you might think. It takes a lot of technology to get it done right. 




You don't just want to weld the crack up. That's not always a solid repair. Instead, you want to use a recasting procedure, where the cracks get gouged out and the molten material gets poured back into that crack and recasts that cylinder head. It then gets remachined for a good repair.

It's not something that most guys can do, and it's really time consuming. 

That's why we carry complete cylinder heads, whether reman or new, and that's what you're going to need to get your engine back up and going for another reliable million miles. Check out our Signs You Need to Replace Your Cylinder Head, for more reasons you might need a new head.

If you're looking for help installing your diesel engine cylinder head, we have a some helpful install tips!


So when you're replacing your cylinder head, if you've got cracks, make sure you're fixing the overall problem. Check your liner protrusion and make sure you're not going to blow another head gasket. We want you to go another million miles!



Want more help with your cylinder head, or another diesel engine component? We have ASE certified techs on staff to help you out! Give 'em a call at 844-304-7688, or you can request a quote online!