I. Introduction

In the RAM 6.7L diesel engine, the grid heater bolt is located in the intake manifold and is used to preheat the intake air during cold starts to ensure a smooth engine start in cold weather. However, just a while ago, multiple real user accidents proved that the part had a design flaw that could lead to serious engine failures, but there was no official 6.7 Cummins grid heater bolt recall.

II. Dreaded 6.7 Cummins Grid Heater Bolt Failure

An owner of a 2017 RAM 3500 noticed the Check Engine light came on after approximately 110,000 miles. A fault code reading using an OBD II scanner showed P2609, Intake Heater Circuit Failure.

Further inspection revealed that the heater bolts were loose and the battery harness connections were overheating, causing the bolts to melt. The melted bolt and nut could have dislodged and traveled into cylinder six, causing severe damage to the piston, valve, and block. The estimated repair cost is approximately $25,000. (Source: https://www.cumminsforum.com/threads/grid-heater-failure.2578604)

But this isn't a rare case. The same issue was found in another 2017 RAM 6.7L diesel. An owner, Abe, with about 100,000 miles on the clock, experienced knocking and shaking in the engine after only 5 miles on a hunting trip. After being towed to the local RAM dealer for service, it was discovered that a heater screw had broken and debris had entered cylinder six, causing damage to the piston, a bent intake valve, and a cracked cylinder head. Again, the repair cost was in the five figures.

III. Why the Dreaded 6.7 Cummins Grid Heater Bolt Failure Accident?

• Thermal expansion and contraction: During engine operation, temperature changes lead to expansion and contraction of the screw material, which may cause metal fatigue under long-term action.

• Vibration fatigue: Constant vibration during engine operation can put stress on the screws, gradually causing them to break.

Possible consequences if a heater bolt breaks

• Piston damage: Fragments of the dislodged screw may strike the top of the piston, causing serious damage.

• Engine scrap: Fragments may cause damage to the cylinder block, valves, and other components, requiring replacement of the entire engine in severe cases. Repairs are very expensive, often in the five-figure range.

• Carbon buildup and blocked air intake: The design of the heater screws can lead to carbon buildup, which in turn blocks the air intake passages. This can reduce intake efficiency, affecting the engine's power output and fuel economy.

Models and years affected

I've checked most of the forums for owner comments, and in fact, the vehicles that are failing are mainly RAM 6.7L diesel models built after 2013 or (some owners think 2012). Many owners in this range are not experiencing the problem, so there's no need to panic too much. Additionally, the broken bolt is not an issue that can't be maintained or fixed in advance.

IV. The Dreaded 6.7 Cummins Grid Heater Bolt Failure Solution

Regular Inspection and Replacement

• Best value for money but more time-consuming

• Timing of inspection: It is recommended that the heater bolts be inspected during each oil change or routine maintenance.

• Judging the state of the bolts: Check whether the bolts are loose by shaking the test; observe whether there are cracks, corrosion, or other signs of abnormality on the surface of the bolts. Replace them promptly if there are problems.

Upgrade Alternatives

• Ideal for the cold north, convenient but requires some expense

• Replace the position of the heater screws: The position of the heater wires, located under the heat shield, will be adjusted to avoid direct exposure of the screws to the intake passages.

• Installation of screw heaters only: This design eliminates the need to penetrate the screws and still provides preheating and optimizes intake airflow, reducing carbon buildup and thus reducing the risk of screw breakage.

  • This completely solves the problem of damaging the engine compartment. However, the heating function is also removed.

  • To compensate for this, the position of the heating wire under the heat shield was changed to the leftmost end of the intake pipe, and a spiral heater was used so that the SPELAB 6.7 Cummins intake horn upgrade retains the heating function.

    Use of SPELAB's 6.7 Cummins Grid Heater Delete: SPELAB has developed an insulated delete plate that removes the heater bolts directly, based on the source of the failure.

SPELAB Intake Horn/Manifold Grid Heater for 6.7 Cummins

2007-2024 Dodge Ram 2500/3500

$399.99

Buy Now

• • When you use the gird heater delete + coil heater bolts + SPELAB's 6.7 Cummins Intake Horn, you can maintain good performance in cold weather while solving the dreaded 6.7 grid heater bolt fix issue.

Completely Removes Heater Bolts

• Convenient and complete solution to the problem, but there are environmental limitations

• For vehicles located in warmer climates, owners may consider removing the heater bolts completely with a modified gird heater delete kit.

• One user indicates, “I haven't had a grid heater for the better part of 10 years on my truck, and it's started just fine in the teens. I rarely plug it in to keep mice from wanting to create a new home with the warmth of the engine. Running a synthetic oil that stays fluid down to sub-zero temps also helps.”

V. FAQ

Q1: How to determine whether the heater bolts have failed?

• Observe whether the engine is difficult to start from cold, whether it is accompanied by white smoke or strange noise; you can also check the surface of the bolts for cracks, looseness, or corrosion.

Q2: How does SPELAB's 6.7 Cummins Intake Manifold Upgrade help prevent heater bolt failure?

• The intake manifold optimizes airflow, improves combustion efficiency, and reduces carbon buildup, lowering the risk of heater bolt damage.

Q3: Is it safe to completely remove the heater bolts?

• In warm climates, complete removal of the heater bolts will not affect engine starting performance. In colder climates, it is recommended to equip a coil heater and optimize the air intake system to ensure smooth engine starting in winter.

Q4: How can I prevent the heater bolts from breaking?

• Check regularly and use high-quality alloy bolts. Adopt SPELAB's delete plate optimized design to eliminate the problem of falling bolts from the root.

Q5: What are the main advantages of the SPELAB retrofit program?

• Eliminates the risk of heater bolt breakage. Combined with a coil-over heater, the engine can still start smoothly in cold conditions.

VI. Summary

Design flaws in heater screws can lead to serious engine damage that requires large sums of money to repair. Therefore, regular inspection and maintenance are key to preventing problems. For long-term solutions, upgrade alternatives such as installing SPELAB's 6.7 Cummins intake manifold upgrade and screw-in heaters are recommended.

However, as SPELAB is a performance tuning store dedicated to improving the user experience, we need more ideas and thoughts to keep iterating our products, so if you have any questions or suggestions, leave your feedback.