Customers regularly come into the shop and see a warning sign sitting on the counter next to a grid heater from a RAM 6.7 engine. Understandably the information doesn't make it to all of the people it pertains to. Given the gravity of the issue, we decided to bring it up here.
The RAM 6.7 engine, from approximately 2007 to now, has a grid heater with a known flaw: it has a nut on the internal side that has been found to melt off and ultimately drop into one of the engine cylinders. Having that chunk of metal bouncing around inside your cylinder while your driving causes damage that ranges from significant to catastrophic. This has been found especially in the 2013 and new model years.
What does a grid heater do?
Gas engines use a spark plug to ignite the air/fuel mixture in a cylinder. This results in the combustion within the cylinder that ultimately drives the truck. Diesel engines don't use spark plugs, instead, the design of the engine is such that heat created by the much higher compression in each cylinder is enough to cause the combustion. In warm weather this works fine. However, in cold weather it is more difficult for the cylinders to generate the heat necessary to cause the combustion. This is where heating elements come in.
Ford and GM use glow plugs as heating elements. Each cylinder has a glow plug and when the ignition is turned the plugs glow red hot and help heat the air inside the cylinders to facilitate starting in colder weather.
Dodge decided to go with a different approach: the grid heater. Instead of having an individual heating element for each cylinder, Dodge uses a single heating grid that heats the incoming air going to all cylinders.
To do this, current is applied to an insulated relay that passes through the plate, from the top to the bottom. That current is passed on to the grid heating element which heats the air passing through that is routed to the intake manifold and then to each cylinder.
The problem comes when the nut on the underside of the plate gets fatigued to the point of failure and eventually melts off of the relay. When the nut falls off it drops into the intake manifold and eventually makes it way to one of the cylinders, typically cylinder 6.
Once a chunk of metal is bouncing around inside of a cylinder in the extreme conditions of a running engine, significant damage occurs.
The piston will become pitted, deformed, and completely compromised. The cylinder wall will likely become scored and suffer basic failure. In short, the engine will likely need to be replaced. This is a widely known issue that has existed for over a decade. There is no recall on this.
How can the engine be protected from the grid heater flaw?
Option 1, the short answer, is to remove the grid heater. If you are not going to try to start your truck in a cold climate, this is a viable option. Removing the stock grid heater and replacing it with a plate that has no grid and therefore no relay that will fail solves the problem. That being said, if you do end up in a cold climate, the benefit of the pre-warming will be lost. The loss of preheating in cold climates can result in difficulty starting, rough running until the engine warms, and possibly trouble codes being thrown.
Option 2 is to replace the grid heater with a system of different design.
Banks Power, widely known for their performance product lines, has a Monster Ram intake elbow with a design that removes the grid and uses a different type of heating element that eliminates the risk of unwanted materials dropping into the engine.
An additional feature of this design is the greatly increased air flow through the unrestricted billet plate. This provides for increased throttle responsiveness as well as enhanced fuel economy.
The Ram 6.7 engine engineers did not foresee the problem with their grid heater dropping shrapnel into the engine. Despite knowing about the problem for over a decade there has been no recall and no change in the design of the engine. If you own a 6.7, you are at risk. Will this failure occur in every engine? No. Will it occur in yours? There is no way to tell. You might get some warning by way of a check engine light accompanied by a P2609 and/or P0542 code, both of which address voltage irregularities with the intake air heater circuit. The codes are not going to differentiate between a failing bolt that is generally not conducting current, and a failed bolt, which means the nut is bouncing around in the intake manifold or has already dropped into a cylinder. In short, waiting for the codes might mean you have waited too long. A solution that allows for the retention of pre-heating and increases air flow is the Banks Monster Ram, which can be installed at less than a tenth the cost of replacing an engine.
For more information on this, call Standard Diesel. We will be happy to answer your questions.
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