6.7 Cummins Grid Heater Bolt Failure

A new problem has developed on the 6.7 Cummins, and it’s happening at an alarming rate, enough for us to now consider it a common problem. The factory grid heater has a bolt and stud on the bottom side of it. From heat and deterioration the bolt has a tendency to fall off, which then sends it through the intake manifold where it winds up inside cylinder #6.

The bolt in the cylinder causes tons of internal damage to the piston, valve, and the cylinder head. Ultimately, this results in completely engine failure the vast majority of the time. In the instances where it does not cause total failure, you are still left with thousands of dollars in repairs to replace the piston, valve, and re-machine the head.

In this guide we’re going to discuss the cause of 6.7 Cummins grid heater bolt failure, how to diagnose and check the bolt for issues, and upgrades or kits to fix and prevent failure in the first place.

Understanding the Grid Heater Bolt Problem

The bottom side of the factory grid heater has a 12-volt metal conductor that is held in place by a stud and a bolt. This conductor is what passes voltage to the grid heater for it to generate the heat necessary to start the vehicle.

Heat ultimately leads to the deterioration of this bolt and stud, which can cause it to partially break, or completely fall loose. The grid heater feeds into the intake manifold, so the bolt falls down into the manifold and then get sucked into a cylinder, which is usually cylinder #6.

Metal inside the cylinder wreaks havoc taking out the piston, valves, and damaging the head. The grid heater bolt failure affects 2007.5-2018 models, there haven’t been any (or very few) instances of failure in 2019+ models.

P2609 and P0542 Engine Codes

Since the bolt helps provide voltage you might actually get a warning in advance before the bolt actually fails or falls into the cylinder in the form of a P2609 or P0542 code.

Here is what these two codes mean:

• P2609: “intake air system heater voltage/performance” is an indicator that the bolt is no longer conducting current properly
• P0452: “evaporative control system pressure sensor low input” this sounds like an EVAP related issue but is commonly caused by the heater relay which can indicate an issue with the bolt

Both of these engine codes are early warning signs that the bolt is failing. Additionally, the bolt could have already broken off but just not found its way into the engine yet. So, if you get one of these codes pull the grid heater and inspect it immediately.

Testing the Grid Heater Bolt

In the picture above, you can see a metal plate or rod looking structure that the bolt is holding in place. To test if the bolt is close to failure, you’ll want to wiggle the plate and see if there is any play in it.

If the connector wiggles around and has play then the bolt is near failing. If it is securely and tightly held in place then you are safe for now.

Here is a video demonstration:

How to Prevent 6.7 Cummins Grid Heater Failure

1. Weld the bolt in place
2. Delete the grid heater
3. Upgrade the manifold and heater

We have a few options for preventing engine failure from the grid heater bolt. These options range from free to a couple hundred bucks, to around a grand. Each have their set of pro’s and con’s so I’ll discuss them each in-depth below.

These options are in order of cheapest to most expensive, not necessarily in the order of the best to worst. Ultimately, my favorite option is deleting grid heater with a plenum upgrade and then tapping it with a heater coil for cold climates – but I’ll let you decide based on my opinions below.

1) Weld the bolt in place

The cheapest solution to this problem is to weld the bolt into place. You just need to pull the heater grid and then either self-weld it or take it to a shop which will probably run you $50 or so.

The pro’s to this option are that it is the cheapest and it doesn’t require any additional modifications. It allows you to retain all the factory equipment while also mitigating the risk. The downside is that it isn’t a guaranteed solution in the sense that the bolt is still there. A strong weld should prevent the issue in 99% of the time, but it isn’t as guaranteed as the following two options which completely remove the bolt.

Price: $0-$50

2) Grid heater delete kit

Deleting the grid heater is a sure-fire way to prevent issues with the bolt by completely removing the whole assembly. The best way to do this is with a kit that usually comes in the form of a delete + high-flow plenum upgrade. So there is both the benefit of fixing the issue but also improving airflow which offers some minor performance benefits.

This is the best option to completely mitigate the bolt problem without breaking the bank, with a kit running around $200. Now, the downside is that it completely deletes the heater grid, which is important for cold starts so this generally isn’t the best option for those in cold climates who have to frequently start their vehicles in below-freezing temps.

Now, if you do live in a cold climate there is an option. You can tap the factory intake manifold and install a heater coil (BD offers one for about $140) which will solve the cold start issues. All in this will run you $350 or so, maybe a little more if you need some help tapping a bolt hole into the factory manifold.

Price: $199-$214 for the kit + $140 for the heater coil if needed
Buy Here: Fleece Performance Grid Heater Delete

3) Intake manifold and heater upgrade

The top-of-the-line solution here is to do a full intake manifold and heater grid upgrade. This will remove the factory bolt while retaining the grid heating functionality while also providing performance benefits.

The best option here is Banks Monster-Ram Intake System. The pro’s are that it does everything: fixes the problem, adds performance, and keeps the grid heater(via a heater coil similar to how you would do it above) for people in cold climates who need it. The only main downside or con here is that this costs around a $1,000 making it an expensive option. There are a few other upgrade kits on the market but Banks also includes a heater grid all in one kit where other options require it to be upgraded separately.

Price: $968
Buy Here: Banks Monster-Ram Intake Manifold & Grid Heater Upgrade