Fuel heater grid?

[RichardLong]

3rd Ram, 2nd diesel, but still a newbie.
Hearing a CHUFF noise after I wait for the light to go out on start up.
2008, 6.7, 2500 just turned 100K mi. I've had it for 10K miles. Live in So. AZ & SoCal. Read on one of the web sites that where I live the fuel grid heater is kind of superfluous. Also noted in a story about the grid corroding/burning out and going into the intake. Can I just pull the relay(s)? If so where are they and what are they labelled as?

 

[Ozymandias]

Don't burn out, never heard of that.
No need to wait for the light, start like a gasser.
Grid heater is for emissions and below -30°.

 

[RichardLong]

Don't burn out, never heard of that.
No need to wait for the light, start like a gasser.
Grid heater is for emissions and below -30°.

Thanks, Can't remember where I saw report of corner corroding out and fowling piston. Just concerned

 

[Jim W]

I agree with Ozzy, I still have my grid heater on my truck which is similar to your truck. I also still use the heater since I live in Northern IL., makes it easier to start the truck.

 

[cerberusiam]

Don't burn out, never heard of that.

They can and do, frequently with disastrous results. The grid heaters on 6.7's are significantly different than a 5.9 and a very real problem exists. The mounting of the 6.7 grid is in the intake plenum not under the air horn, the mounting system has a nut on a stud that holds the gird rigid. Age, usage, EGR, et., conspire to burn the stud off the grid because the mount is part of the grounding system. When that happens it goes right into a cylinder and makes a mess. The acid created from he heavy electric current and exhaust gasses expedite the deterioration. It is much more likely to happen when the grids are more active, like colder climates, but that doesn't mean a warm weather truck won't see issues. Grids are active under 60 dgrees so very few place sin the lower 48 are exempt.

OP lives in AZ and SoCal, grid heater isn't needed in those areas for normal operation. If he did go the sub zero climates frequently then it might be needed. Considering the design and potential for damage, I would do a grid heater delete on ANY 6.7 I owned, or, replace it with a new unit and monitor.

 

[DonFitzwater]

They can and do, frequently with disastrous results. The grid heaters on 6.7's are significantly different than a 5.9 and a very real problem exists. The mounting of the 6.7 grid is in the intake plenum not under the air horn, the mounting system has a nut on a stud that holds the gird rigid. Age, usage, EGR, et., conspire to burn the stud off the grid because the mount is part of the grounding system. When that happens it goes right into a cylinder and makes a mess. The acid created from he heavy electric current and exhaust gasses expedite the deterioration. It is much more likely to happen when the grids are more active, like colder climates, but that doesn't mean a warm weather truck won't see issues. Grids are active under 60 dgrees so very few place sin the lower 48 are exempt.

OP lives in AZ and SoCal, grid heater isn't needed in those areas for normal operation. If he did go the sub zero climates frequently then it might be needed. Considering the design and potential for damage, I would do a grid heater delete on ANY 6.7 I owned, or, replace it with a new unit and monitor.

Got any pics? Not saying it isn’t happening but me and my circle of friends have been running 6.7s since 2010 and needless to say it’s cold here in Alaska. We’ve not had failures...........thinking I’ll take a peek at a few of them though! I’ve had a few vp trucks back in the day that had intake heaters go bad but they just stopped working due to “open”

 

[Jim W]

I too have not heard of that. My truck is an early 2008 built and sold in 2007 and I thought the grid heater was under the air horn like the 5.9L. When I added my boost bolt I remember that the grid heater was under the air horn. I could be incorrect or there could have been a change later in the engine series. It has been at least 10 years since I was in this area so, I am relying on my 70 year old brain to remember!

 

[DonFitzwater]

https://www.turbodieselregister.com/threads/grid-heater-bolt-came-loose.265513/

I found this thread from last year. It took a little to refresh my memory on the topic but I got it now.

 

[cerberusiam]

I have never seen a oil cooler on a Cummins leak but it happens. I have never seen a heat exchanger fail on these trucks but it happens. People will tell you they never heard of 6.7 losing a HG either, we all know how bogus that is. I have seen pictures of the results of the grid heater bolt being sucked into a cylinder, take it on faith you don't want it to happen.

If you want to see what happens and how it can happen, pull the grid heater out and look at the design and the installation. The grid heater on a 5.9 is square block at the base of the intake horn, the 6.7 grid is part of the intake cover and much different design. Just note that pulling the grid heater and intake cover on a 6.7 engine will usually end up being an expensive $$$$ proposition. If you have any qualms about openign the wallet, drive it till it dies or you trade it.

 

[TCDiesel]

I just jump in and start, its the Long heat cycles ( NOT Running) that take its toll on the bolt/Nut Sure when its -0 out I'll let it cycle but temps above that I jump in push on the start button to ACC, wait 2-3sec's step on the brake Than push the start button to Run. Truck starts right up, when the grid heaters cycle air is cooling the heat fins/bolt to they don't get hot when running.

Ok, on edit fins/bolt

 

[cerberusiam]

Note that the fins are not the issue, it is the grounding end of the grid that loses contact and arcs enough to burn the bolt thru.

 

[RichardLong]

Well after reading the 1st couple posts I choose to ignore the situation and I didn't follow the post. Now the situation has deteriorated. A weird noise like chunking then rattle, whirring rattle, and flutter, thwap and exhaust plink, engine went smoother, quieter, and sped up, then everything went back to normal. Some where in there a check engine light with the P0541 code appeared. I've ordered the "factory CD" from tech authority but while I'm awaiting that I would really like to talk with a 6.7 owner or some one has been down this rabbit hole. I'm a long time hot rodder and OK mechanic, but certainly not a diesel guy and all the junk on top of this Cummins intimidates me. Not sure I want this truck immobilized in my yard.

 

[RichardLong]

They can and do, frequently with disastrous results. The grid heaters on 6.7's are significantly different than a 5.9 and a very real problem exists. The mounting of the 6.7 grid is in the intake plenum not under the air horn, the mounting system has a nut on a stud that holds the gird rigid. Age, usage, EGR, et., conspire to burn the stud off the grid because the mount is part of the grounding system. When that happens it goes right into a cylinder and makes a mess. The acid created from he heavy electric current and exhaust gasses expedite the deterioration. It is much more likely to happen when the grids are more active, like colder climates, but that doesn't mean a warm weather truck won't see issues. Grids are active under 60 dgrees so very few place sin the lower 48 are exempt.

OP lives in AZ and SoCal, grid heater isn't needed in those areas for normal operation. If he did go the sub zero climates frequently then it might be needed. Considering the design and potential for damage, I would do a grid heater delete on ANY 6.7 I owned, or, replace it with a new unit and monitor.

In other discussions on other sites the opinion seems to be that the "grid heater" also performs some function to do with the DPF and the soot burn off cycle so that deleting might cause soot build up and emissions malfunction?

 

[cerberusiam]

Not any way I can think of would the grid heater have an impact on the DPF. The regen is all about creating enough heat in the exhaust with extra fuel to burn the soot out, grid heater doesn't get that hot. Its main emissions function is to limit cold start smoke.

 

[BigPapa]

Here's what you're looking at.

 

[RichardLong]

Here's what you're looking at.

View attachment 117014

Thanks

 

[RichardLong]

Not any way I can think of would the grid heater have an impact on the DPF. The regen is all about creating enough heat in the exhaust with extra fuel to burn the soot out, grid heater doesn't get that hot. Its main emissions function is to limit cold start smoke.

Thanks, What does the pipe around the top front of the engine and leading into the intake do?

 

[Bob4x4]

The tube delivers the exhaust gases that the egr valve allows into the intake stream

 

[RichardLong]

The tube delivers the exhaust gases that the egr valve allows into the intake stream

Thanks, looking at profile, please let that be Riverside, CA? If so I'm looking for competent, honest Cummins diesel shop in south west. Some times I'm in Vista, East of Oceanside, CA.

 

[RichardLong]

Not any way I can think of would the grid heater have an impact on the DPF. The regen is all about creating enough heat in the exhaust with extra fuel to burn the soot out, grid heater doesn't get that hot. Its main emissions function is to limit cold start smoke.

Thanks, Not to start a fight, just trying to get the dynamics of how it works. Answer to another post says EGR recircs to intake track which goes to plenum and back across grid heater right? does the EGR have the soot cleaned from DPF or is that some how channeled separate to the exhaust system?