If you've spent any time under the hood of a heavy-duty truck, you know that heat is the enemy, which is why a pusher coolant reroute kit 6.7 cummins upgrade has become such a staple for guys who actually use their rigs. These engines are absolute workhorses, but they have a bit of a literal "hot spot" that's been nagging owners since the 6.7 first hit the market. While the front of the engine gets plenty of flow, the back cylinders—especially cylinder number six—tend to get treated like an afterthought by the factory cooling system.
It's one of those things where the factory design is "good enough" for a stock truck doing grocery runs, but as soon as you start adding power, towing heavy trailers up a grade, or just living in a climate where the asphalt melts in July, that cooling deficiency starts to matter. If you've ever seen a freeze plug pop out of the back of the head while you're miles from home, you know exactly why people are so keen on bypassing the stock setup.
Why the Back of the Engine Struggles
The 6.7 Cummins is a long engine. By the time the coolant makes its way from the water pump through the block and up into the head, it's already picked up a lot of heat. Because of the way the coolant path is routed from the factory, the flow sort of "dead-ends" or slows down significantly at the very back of the cylinder head. This creates a pocket of high-pressure, high-temperature coolant that just hangs out around cylinder six.
When things get too hot back there, the pressure builds up. If you're lucky, you just get some localized boiling or "hot spots" that can lead to premature wear. If you're unlucky, that pressure pushes out the rear freeze plug. If that happens while you're at 70 mph on the freeway, you're going to lose your coolant faster than you can pull over, and that's a recipe for a warped head or a cracked block. The Pusher kit solves this by giving that coolant an "exit strategy." Instead of letting it pool and pressurize, it provides a dedicated path for that hot coolant to flow out of the back of the head and back into the cooling system where it can actually be cooled down by the radiator.
What Makes the Pusher Kit Different
There are a lot of DIY ways to reroute coolant, and you'll see guys on forums trying to piece together kits from hardware store brass fittings and heater hoses. Honestly, it's just not worth the risk. The pusher coolant reroute kit 6.7 cummins is engineered specifically for this engine bay, which is cramped to say the least.
One of the first things you'll notice when you unbox the kit is the quality of the fittings. Pusher uses high-quality, CNC-machined components that are designed to fit perfectly into the existing ports. They don't just throw a rubber hose in the box and call it a day; they use braided lines that can handle the vibration and heat of a diesel engine without softening or leaking over time. Plus, let's be real—the anodized finish looks pretty slick under the hood. If you're proud of your engine bay, you don't want a bunch of plumbing-aisle hardware sticking out like a sore thumb.
The kit also addresses the coolant bypass valve. Some cheaper setups just let the coolant flow constantly, which can actually make the truck take forever to warm up in the winter. Pusher's design keeps the thermodynamics in mind, ensuring you get the protection you need when the engine is hot without sacrificing your heater performance on a cold morning.
The Reality of the Installation
I'm not going to lie to you and say this is a five-minute job. It's not "hard" in the sense of needing a degree in mechanical engineering, but it's definitely "tight." The back of the 6.7 Cummins is tucked right up against the firewall. If you have big hands, you're probably going to lose some skin on your knuckles, and you'll definitely learn some new curse words.
The most important thing is to make sure the engine is completely cold before you start. You're going to be opening up the cooling system, and nobody wants a face full of 200-degree Dex-Cool. You'll also need a good set of tools—specifically some slim ratchets or swivel sockets to get to that rear port. Once you get the factory plug or fitting out, the rest is pretty straightforward. You're basically just connecting the dots between the back of the head and the thermostat housing or the upper radiator hose area, depending on which version of the kit you're running.
A little tip for when you're doing this: take the time to clean the area around the rear port before you remove the factory plug. Dirt and grime love to settle back there, and you don't want any of that falling into your cooling system while the hole is open. Once the new Pusher fitting is seated and the lines are routed, just make sure everything is clamped down and away from anything that moves or gets excessively hot (like the exhaust manifold or turbo).
Benefits Beyond Just Safety
While the main reason people buy a pusher coolant reroute kit 6.7 cummins is to prevent a catastrophic freeze plug failure, there are some secondary benefits that people often overlook. For one, your engine is going to run more consistently. When you eliminate that hot spot at the back of the head, the temperature across all six cylinders becomes much more uniform. This is huge for the long-term health of your head gasket.
Head gaskets often fail because of uneven expansion and contraction. If the front of the head is at 190 degrees and the back is at 220, the metal is expanding at different rates. That puts a lot of shear stress on the gasket material. By equalizing those temps, you're giving your head gasket a much easier life.
Also, if you've deleted your EGR (for off-road use, obviously), you've already changed the way coolant flows through the head. A reroute kit is often considered the "finishing touch" for a modified 6.7 cooling system. It rounds out the package and ensures that the modifications you've made aren't putting undue stress on the parts you kept.
Is It Worth the Investment?
If you ask ten different Cummins owners if they need a coolant reroute, you'll get ten different answers. The guys who just drive to the office and back might tell you it's overkill. But if you talk to anyone who actually works their truck—hotshotters, heavy towers, or the guys pushing 600+ horsepower—they'll tell you it's cheap insurance.
Think about it this way: the cost of the kit is a fraction of what a tow bill would be if you broke down in the middle of nowhere. It's a drop in the bucket compared to the cost of a new cylinder head or a full engine rebuild. In the world of diesel performance, we spend a lot of money on things that make the truck go faster or sound louder. It's nice to spend a little bit of money on something that actually makes the truck last longer.
Final Thoughts on the Pusher Setup
At the end of the day, the pusher coolant reroute kit 6.7 cummins is one of those upgrades that you install and then hopefully never have to think about again. It's not flashy, and it's not going to shave seconds off your quarter-mile time, but it's doing the heavy lifting in the background to keep your engine happy.
If you're planning on keeping your 6.7 for the long haul, do yourself a favor and look into this. It fixes a known weak point with high-quality parts that are built to last as long as the engine itself. Just grab a buddy, a couple of cold drinks, and a good set of wrenches, and spend a Saturday afternoon getting it done. Your cylinder number six will thank you for it, and you'll have one less thing to worry about when you're pulling a heavy load up a steep grade in the middle of summer.