If you own a 6.7 Cummins engine, you know it’s a powerhouse—but even the toughest engines can run into trouble. One of the most common issues? A failing head gasket. Whether you’re noticing white smoke, overheating, or coolant leaks, it’s crucial to address the problem before it leads to costly repairs.
In this guide, we’ll walk you through the symptoms of a failing 6.7 Cummins head gasket, the replacement process, and the costs involved. Plus, we’ll highlight top head gasket brands like MAHLE Victor Reinz, Cometic, and Alliant Power to help you make the best choice for your engine.
Common 6.7 Cummins Head Gasket Symptoms to Watch For
A failing head gasket won’t blow overnight—it’s going to throw out warning signs long before it becomes a major issue. Catch it early, and you could save yourself thousands in repairs. Here’s what to watch for:
Engine Overheating
If your temperature gauge is creeping higher than normal, don’t ignore it. A blown head gasket disrupts coolant flow, causing hotspots and overheating. If you keep driving like this, you’re asking for warped cylinder heads—or worse, a cracked block. If your truck is running hotter than usual, check for coolant loss and investigate immediately.
White Smoke from the Exhaust
Thick, white smoke isn’t just a cold-weather startup quirk. If it lingers after warm-up, coolant is likely leaking into the combustion chamber and burning off as steam—a telltale sign of head gasket failure. The longer this goes on, the more damage it’s doing.
Coolant and Oil Mixing (The Milky Mess)
If your oil dipstick or coolant reservoir looks like a milkshake, that’s a serious problem. Coolant and oil are mixing—something that should never happen in a healthy engine. This sludge kills lubrication, leading to premature engine wear and even bearing failure. If you catch it early, you might save your bottom end.
Loss of Power and Rough Idling
A blown head gasket means your cylinders aren’t sealing properly, and that means compression loss. If your Cummins is feeling sluggish, misfiring, or idling rough, your gasket might already be on its way out. Check for bubbling in the coolant reservoir while the engine runs—it’s a dead giveaway of a combustion leak.
Coolant Leaks or Low Coolant Levels
Constantly topping off coolant but not seeing an external leak? That coolant is going somewhere, and it’s likely being burned inside the engine. On the flip side, visible leaks around the head gasket area could mean the seal is failing externally. Either way, it’s time for a fix.
Don’t Ignore the Signs—Fix It Before It’s Too Late
Letting a bad head gasket go unchecked can turn a repair job into a full rebuild. If you’re noticing any of these warning signs, don’t wait—get ahead of the problem before it leads to catastrophic engine failure.
Need trusted, high-quality replacement parts? Shop 6.7 Cummins head gaskets now and get your truck back to peak performance.
How to Perform a 6.7 Cummins Head Gasket Replacement
Replacing a head gasket on a 6.7 Cummins isn’t your average weekend wrenching job. It’s time-intensive, requires precision, and if done wrong, can cause even bigger problems down the road. But if you’ve got the tools, patience, and mechanical know-how, you can tackle it. Follow these steps carefully to get the job done right.
Step 1: Confirm It’s the Head Gasket
Before you start pulling parts, make sure the head gasket is actually the issue. A compression test or a leak-down test will confirm cylinder pressure loss. You can also check for bubbles in the coolant reservoir while the engine runs—a telltale sign of a combustion leak.
Step 2: Gather Your Tools and Parts
This isn’t a quick job, so make sure you have everything on hand before you start. Here’s what you’ll need:
- Torque wrench – Precision is critical when torquing head bolts.
- Socket set – Metric and SAE, depending on your truck’s setup.
- Gasket scraper – Old gasket material must be completely removed.
- Coolant catch pan – You’ll be draining and replacing coolant.
- Head gasket kit – Don’t skimp here. We recommend Mahle/Victor Reinz for stock replacements or Cometic MLS for performance builds.
- Head bolts or head studs – If you’re running more boost or tuning, step up to ARP head studs for better clamping force.
Step 3: Drain Fluids and Strip It Down
- Disconnect the battery – You don’t want power running while you’re deep into the engine.
- Drain coolant – Make sure to properly dispose of it—coolant is toxic.
- Remove intake manifold, exhaust manifold, and valve cover – Label hoses and wiring as you go to make reassembly easier.
Step 4: Pull the Cylinder Head
Once everything is out of the way, carefully loosen the head bolts in the proper sequence (reverse torque pattern). If the head is stuck, resist the urge to pry it off—use a rubber mallet to gently break it free. Handle with care—these heads are heavy, and you don’t want to damage the mating surface.
Step 5: Inspect Everything Before Reassembly
- Check the cylinder head for cracks or warping – If it’s not perfectly flat, have it resurfaced before reinstalling.
- Inspect the block for signs of erosion – If there’s damage, you may need more than just a gasket replacement.
- Clean the mating surfaces completely – Any leftover debris or old gasket material will prevent a proper seal.
Step 6: Install the New Head Gasket
- Place the new gasket carefully – It only fits one way—double-check alignment before continuing.
- Install new head bolts or head studs – If using ARP head studs, follow their torque sequence exactly.
- Torque to spec – Use a calibrated torque wrench and follow Cummins’ recommended tightening sequence.
Step 7: Reassemble and Test
- Reinstall everything in reverse order.
- Refill the coolant system with Cummins-approved coolant.
- Fire up the engine and check for leaks and overheating.
- Retorque head bolts or studs after a few heat cycles, if required.
6.7 Cummins Head Gasket Replacement Cost
Unfortunately, blowing a 6.7 Cummins head gasket isn’t just frustrating—it’s expensive. Whether you’re handling the job yourself or paying a shop to do the work, you need to know what you’re getting into. Here’s what to expect when it comes to costs and why choosing the right parts can make all the difference.
Parts Cost – Go Cheap, Pay Twice
A basic head gasket will run you $200 to $500, but most Cummins owners don’t stop there. Complete head gasket kits, which include seals, head bolts, and other critical components, range from $500 to $1,000. These kits save you from chasing down individual parts and ensure everything seats correctly.
If you’re pushing extra power or running higher boost, consider upgrading to a kit with ARP head studs, which provide superior clamping force and reduce the risk of future failures. Alliant’s Head Gasket Kit with ARP Head Studs is a great option if you want extra durability.
Labor Costs – Shop vs. DIY
If you’re paying a professional, expect to drop $1,500 to $3,000 in labor costs alone. This isn’t just a head gasket swap—it’s a full top-end teardown.
For DIYers, the savings are huge, but the work isn’t for beginners. If you don’t have the right tools (or patience), paying a shop might be worth it.
Additional Repairs – The Hidden Costs
The head gasket itself might be the least of your worries. If your cylinder head is warped or cracked, you’re looking at an extra $500 to $1,000 for machining or replacement. And don’t forget to budget for fresh coolant and oil after the repair—another $100 to $200.
Total Cost Estimate – Plan for $2,000 to $4,500
When it’s all said and done, a full head gasket replacement will cost between $2,000 and $4,500, depending on the parts used and whether you’re handling the labor yourself. Cutting corners on cheap gaskets or reusing head bolts will almost always lead to another failure down the road—so do it right the first time.
Top Head Gasket Brands for 6.7 Cummins Engines
Choosing the right head gasket is essential for ensuring durability, performance, and a leak-free seal under high pressure. At Diesel Power Products, we carry trusted brands known for their reliability and quality construction. Here are a few favorites:
Mahle/Victor Reinz Head Gaskets – These OEM-quality gaskets provide a perfect factory fit and excellent sealing performance for stock and slightly modified applications. If you’re looking for a direct replacement with proven durability, Mahle/Victor Reinz is a solid choice.
- Mahle/Victor Reinz Head Gasket (07.5-12 6.7L Cummins)
- Mahle/Victor Reinz Complete Head Gasket Set (07.5-12 6.7L Cummins)
Cometic Head Gaskets – Designed for high-performance and modified engines, Cometic MLS (Multi-Layer Steel) gaskets provide superior sealing, making them ideal for boosted and high-horsepower Cummins builds.
Alliant Head Gaskets – A premium, heavy-duty option, Alliant’s head gasket kits are built for maximum durability and often include ARP head studs for increased clamping force. These kits are an excellent choice for those pushing their Cummins engines to the limit.
By selecting a high-quality head gasket that matches your engine’s needs, you can ensure long-lasting performance and prevent costly repairs down the road.
Tips for Preventing 6.7 Cummins Head Gasket Failure
As you can probably tell by now, a blown head gasket is a costly, time-consuming repair that can sideline your truck when you need it most. The good news? With the right maintenance, you can prevent most head gasket failures before they happen. Here’s how:
- Keep an Eye on Coolant Levels – Running low on coolant is a surefire way to overheat your engine, and overheating is one of the biggest culprits behind head gasket failures. Check your coolant levels regularly and top off with the correct coolant if needed.
- Maintain Your Cooling System – A weak water pump, clogged radiator, or failing thermostat can cause overheating and excessive pressure in your cooling system, leading to a blown head gasket. Stay ahead of these issues by inspecting and replacing worn components as needed.
- Use the Right Fluids – Cheap or incorrect coolant and engine oil won’t do your Cummins any favors. Stick with high-quality diesel-rated engine oil and the manufacturer-recommended coolant to keep everything running smoothly.
- Pay Attention to Performance Changes – If your truck starts idling rough, losing power, or burning white smoke, don’t ignore it. Catching problems early can save you thousands in repair costs down the line.
A little preventative maintenance goes a long way in keeping your 6.7 Cummins head gasket in one piece. Stay ahead of the game, and you won’t be stuck in the shop with an expensive repair bill.
Upgrade Your 6.7 Cummins Head Gasket Today
A failing head gasket isn’t something you can ignore—let it go too long, and you’ll be looking at major engine damage, downtime, and a hefty repair bill. Whether you’re replacing a worn-out stock gasket or upgrading to handle more power, Diesel Power Products has you covered with the best options for your 6.7 Cummins head gasket.
We stock top-quality head gaskets and complete kits from Mahle/Victor Reinz, Cometic, and Alliant, so you can tackle the job with confidence. Whether you need a factory-spec replacement or a heavy-duty upgrade with ARP head studs, we’ve got the parts to keep your Cummins running strong.
Shop 6.7 Cummins head gaskets now and get back on the road with confidence!
FAQs About 6.7 Cummins Head Gaskets
Q: How do I know if my 6.7 Cummins head gasket is blown?
A: If you’re seeing white smoke, overheating, losing coolant with no visible leaks, or finding milky oil, chances are your head gasket is failing. A compression test or leak-down test will confirm if combustion gases are leaking.
Q: How much does a 6.7 Cummins head gasket replacement cost?
A: Expect to pay $2,000 to $4,500, depending on whether you DIY or go to a shop. The gasket itself ranges from $200 to $500, and complete kits (which include bolts, seals, and studs) range from $500 to $1,000. Labor is the biggest factor, costing $1,500 to $3,000 if done professionally.
Q: Can I replace my 6.7 Cummins head gasket myself?
A: It’s possible, but not for beginners. The job requires precision torque specs, proper sealing surfaces, and checking for head warping. If you’re not confident in your mechanical skills, it’s best left to a professional.
Q: Should I use head studs or head bolts for my 6.7 Cummins?
A: This depends on your setup:
- Stock applications – Head bolts are fine for daily driving and factory power levels. A Mahle/Victor Reinz head gasket kit with standard bolts is a reliable choice.
- Tuned or high-boost setups – If you’re running a tuner, bigger injectors, or pushing more boost, ARP head studs provide better clamping force and reduce the risk of another blown gasket.
- Doing the job once? If you want maximum durability, studs are the better long-term investment. Alliant’s Head Gasket Kit with ARP Studs is a great upgrade for reliability.
Q: What’s the best head gasket for a 6.7 Cummins?
A: Mahle/Victor Reinz is the go-to for OEM-quality replacements, Cometic MLS gaskets are great for high-horsepower builds, and Alliant kits offer premium durability with ARP head studs included.
Q: How can I prevent head gasket failure?
A: Regular maintenance is key. Keep your cooling system in check, use high-quality fluids, and don’t ignore early warning signs like overheating or rough idling. Preventative maintenance beats a full engine rebuild every time.