Why Ram Finally Ditched the Infamous Cummins Grid Heater for Glow Plugs

Diesel pickup truck engines have used glow plugs for decades. Well, let me rephrase that: Diesel pickup truck engines not made by Cummins have used glow plugs for decades. Those inline-sixes found under the hoods of Dodges and Rams have historically used grid heaters to help with cold starts, much to the chagrin of owners who have suffered catastrophic engine failures because of them. Ram and Cummins finally kicked the grid heater for 2025 model-year trucks, and while you might think it’s a reliability decision, they say it’s for a different reason.

It’s true that more than a million Cummins-powered Ram trucks have driven just fine for years without any grid heater problems; this is not an issue on every single engine. But when the issue rears its head, it’s a big deal. The fault lies with the hardware that fastens the grid heater on 2007.5 to 2024 model-year trucks. In those pickups, a grid heater bolt can either melt or break off, finding its way into the engine and causing a complete failure.

Anecdotal evidence of this can be found across the internet. It’s been the talk of forums for years, though I’ve never seen it happen myself despite hanging around Midwest truck shops here and there. Still, those who say they’ve experienced a grid heater bolt failure insist it was the cause of their trashed pistons and junked heads. And there’s no predictable mileage range for the problem to occur; some people say theirs broke with more than 100,000 miles on the engine, while others complain that their practically new trucks suffered from the fatal flaw.

Worried owners have deleted their truck’s grid heater as a precautionary measure. Somewhat serendipitously for the folks at Banks Power, those people have caused a surge in sales for the company’s Monster-Ram intake. It’s a performance upgrade that ditches the grid heater for power gains, citing the component’s design that significantly restricts airflow. Ram drivers have treated it as a two-for-one, adding the upgraded intake to their truck for preventative maintenance and more oomph.

Banks has put out several videos and blogs warning owners about grid heater failures. Of course, the company stands to make money off the threat of such a thing happening. These clips are informative nevertheless so if you want a more in-depth look at the problem, check this one out. It has a mechanic’s testimonial after witnessing multiple grid heater failures at his shop in British Columbia:

So, knowing about the grid heater’s potentially negative effect on performance and reliability, you might think that’s why Ram and Cummins ditched it for 2025. But that’s not it. According to Doug Killian, Ram’s chief vehicle synthesis manager who deals with functional design integration, it was the result of rearranging parts on the engine itself.

Starting on the passenger side, Cummins moved the diesel oxidation catalyst closer to the turbo for a hotter, cleaner burn. They also switched from the old intake design that was cast into the engine block; now, a bolt-on intake is used. Killian said they then moved onto the heads, which is where the glow plugs came into play.

“This was really us with Cummins, but [we agreed] it’s time to get to glow plugs,” Killian told me. “And the start time, like in cold weather, just the reliability, it’s almost instant start. It’s down to three seconds versus 30-plus seconds before. So we really, you didn’t hear us mention glow plugs much [in an earlier presentation] because we’re kind of … it’s just a technology we’ve gotten to.”

“It’s been around for decades, and the grid heater was also working fine for startup, but you had to wait,” Killian continued. “Glow plugs—it was time. It was time to get there.”

When I asked if the switch to glow plugs was motivated by anything else, Killian replied, “No, not really. The glow plugs kind of came along for the ride.”

There you have it. Hopefully, this means 2025+ Ram owners won’t have to worry about unanticipated engine death, though it doesn’t really do much for the folks who are concerned their older truck might break without warning. The issue isn’t always covered by warranty since it seems to typically happen after the standard five-year/60,000-mile powertrain coverage expires. And because it’s not a safety problem, I’m not sure an organization like NHTSA will force Ram to recall the trucks.

I don’t expect to stop hearing about grid heater failures anytime soon as there are still tons of 2007.5-2024 Ram HD trucks on the road. That said, nobody wants to see these trucks go down.

Got a tip or question for the author? Contact them directly: caleb@thedrive.com

The post Why Ram Finally Ditched the Infamous Cummins Grid Heater for Glow Plugs appeared first on The Drive.