Detecting a blown Cummins head gasket involves monitoring coolant loss, exhaust smoke, and external leaks. A typical Cummins head gasket measures around 1.5 mm to 2.0 mm in thickness. Opting for a thicker head gasket can enhance durability and better withstand higher cylinder pressures. The choice between OEM and aftermarket options depends on factors such as budget, warranty, and performance requirements. Let’s get into the details.
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How to Identify if my Cummins head gasket is blown?
A failed truck engine head gasket can manifest in various symptoms, and diagnosing the issue typically involves a combination of observation, testing, and inspection. We have published an article titled 3 Symptoms to Check a Blown Head Gasket to provide more information.
However, engine overheating, loss of fluid in the radiator, and white smoke from the exhaust are three of the most common symptoms you may notice when a head gasket is blown. When this occurs, replacing the gasket is a must-do.
After searching online, you may find that there are many different thickness options for Cummins head gasket. You might wonder, which one should I choose?
Why run a thicker head gasket?
It’s important to know the purpose of an oversized head gasket. We’ve covered this topic in detail in our article discussing Why Do You Need An Oversized Head Gasket. In short, an oversized head gasket can be used to correct issues caused by improper deck height or cylinder head warpage. If the engine block or cylinder head has been machined, or if the engine has overheated and caused warping, an oversized head gasket can help restore proper compression and sealing between the cylinder head and engine block.
How Thick Is 5.9 Cummins Head Gaskets and 6.7 Cummins Head Gaskets?
In this section, we will introduce the head gaskets for the all-time favorite Cummins engines, the 5.9L and 6.7L. MJ Gasket offers various oversized Cummins head gaskets to meet your needs, whether you are repairing older engines or enhancing engine performance.
For the 5.9 Cummins, there are three different thickness options of MLS (Multi-Layer Steel) head gaskets available:
- 3958644: Standard, thickness 1.18mm, Grade A
- 3958645: thickness 1.25mm, Grade B
- 3978517: thickness 1.688mm, for Marine engines
For the 6.7 Cummins, there are two different thickness options of MLS head gaskets available:
- 4932210: Standard, thickness 1.2mm
- 5271251: +.020 oversized, thickness 1.7mm
When considering 5.9 Cummins head gasket thickness and 6.7 Cummins head gasket thickness, selecting the right size ensures proper compression and sealing, especially after machining or rebuilding the engine.
How to Know If You’ve Got the Right Thickness of Cummins Head Gasket?
At first glance, the standard head gasket and the oversized one may look almost identical, since the only difference lies in their thickness. So, when purchasing Cummins head gaskets, how can you tell whether you’re getting a standard or an oversized gasket?
First, OEMs usually use different part numbers to distinguish between standard and oversized head gaskets. Most sellers will also include the word “Standard”, “Oversized” or specify the exact thickness in their product descriptions.
But what if you already have a Cummins head gasket in hand and don’t know its part number? It’s simple; you can identify it by checking the holes on the gasket. As shown in the picture below, you can see the difference between the 6.7 Cummins head gasket (Standard) 4932210 and the Oversized version 5271251, which helps you confirm the correct 6.7 Cummins head gasket thickness before installation.
Now, a serious question, OEM or Aftermarket Cummins head gasket?
When choosing between OEM and aftermarket options, there are five factors to consider: Manufacturer reputation, Price, Quality, Product Performance, and Warranty.
Let’s break down what you can expect when purchasing from OEM and aftermarket suppliers. If you buy from the OEM, you can probably get four out of five of the following: Manufacturer, Quality, Product Performance, and Warranty. It’s always safest to purchase from the source and the company responsible for making them in the first place. The only factor missing is Price. If budget is not your top priority, the OEM source will be your best option.
However, there are various aftermarket suppliers available. Price will certainly be one of the factors, but what about Quality, Product Performance, and Warranty? I cannot give you a definitive answer, but what I can assure you is that MJ Gasket will meet at least three out of five criteria.
If you purchase from MJ, you can enjoy our Price, Quality, and Product Performance. If you can spend less but still have a gasket that performs just as well as the OEM, why not? The easiest way to find out is to get your MJ Gasket sample right now, no other words can justify that.
As for Warranty, MJ does not provide a traditional warranty policy. Instead, we take a responsibility-based approach. When an issue arises, we identify the root cause of the gasket failure. If the problem is indeed caused by our gasket, we take full responsibility for it—no extra paperwork, no unnecessary hassle. In the end, we are the ones who manufacture them, so MJ Gasket stands just as accountable as the OEM.
In addition, Flexibility is one of MJ’s strengths. We offer customized assembly kits based on your requirements, whether you need a Standard head gasket or an Oversized head gasket, we can prepare the repair kit that fits your exact needs. This flexibility helps you save time, reduce sourcing complexity, and ensure every component fits your application perfectly.
6.7 Cummins Head Gasket Kit
Our 6.7 Cummins Head Gasket Kit fully reflects MJ Gasket’s flexibility in creating customized repair kits. You can decide exactly what to include in your kit based on your repair needs. Whether it’s a standard 6.7 Cummins head gasket or an oversized one, we can assemble it together with other essential components such as exhaust gaskets, intake gaskets, turbo gaskets, or EGR gaskets.
All you need to do is provide the part numbers and quantities you require, and we’ll build a gasket kit that perfectly matches your specifications. This approach allows you to create the right combination for different 6.7 Cummins engine year models, ensuring compatibility, performance, and convenience in one complete package.
FAQ about Cummins Head Gasket
How can I tell if my Cummins head gasket is blown?
Watch for engine overheating, coolant loss, or white exhaust smoke. These are typical signs of a blown Cummins head gasket that requires immediate replacement to prevent severe engine damage.
Why are there different thicknesses of head gaskets for one type of engine?
A thicker Cummins head gasket helps correct deck-height or cylinder-head warpage after machining, improving durability and maintaining proper compression sealing.
How thick is a 5.9 Cummins head gasket?
A 5.9 Cummins head gasket typically measures 1.18 mm for standard, 1.25 mm for Grade B, and 1.688 mm for marine applications.
How thick is a 6.7 Cummins head gasket?
The 6.7 Cummins head gasket comes in two options: the standard 1.2 mm (part 4932210) and the +.020 oversized 1.7 mm (part 5271251).
