Upgrading a 12-Valve Cummins With a Billet Coolant Pipe

AS SEEN IN OUR MARCH 2026 ISSUE – Buy Now!

FULL SEND DIESEL’S UPPER COOLANT PIPE FOR 12-VALVE APPLICATIONS

Hello everyone! Today we’re going to spruce up the engine bay of our 12-valve with a part that I’m pretty sure (at the moment) no one else makes—a fabricated upper coolant pipe for 1994-’98 12-valves from Full Send Diesel! While this part may not be a “performance” upgrade, it looks great with the rest of the polished parts we’re sporting under the hood of “Stock to Not.”

This kit comes with everything needed to install the coolant pipe—two 5-ply high-temp FSD boots and the stainless steel T-bolt clamps to fasten them! This is definitely a great way to get rid of your potentially 30-year-old rubber coolant hose that watches you replace every other part under the hood when you get paid every week.

ADDING SOME SHINE

Since we’ve already thrown away our old coolant pipe when we tore down the truck, the system doesn’t have coolant in it yet, so the install will be quick and straightforward.

Make sure you’ve got your high-temp boots and clamps all facing the same way, then slide the boots onto the FSD coolant pipe. Having the boots already on the pipe will make it easier to install.

Make sure that you have some clearance in between the ends of the coolant pipe and the thermostat housing elbow/radiator inlet so they’re not touching inside the boots.

Tighten down your clamps! If you’re OCD like me, rotate them all the same way, snug them down, and top the coolant off. Viola!

FINISHING UP

Shout out to Kevin and the guys from Full Send Diesel for supporting us 12-valve guys. We needed some more pretty parts for these old engines.

Head over to fullsenddiesel.com and grab some of FSD’s other cool fabricated parts or merch. You might even win a cool diesel truck if you’re lucky enough!

Photos by Tucker Harris