# What temperature does the fuel filter heater maintain?



## Barry Allen (Apr 18, 2018)

The diesel fuel filter has an electric heater. What temperature does it maintain?


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## Snipesy (Dec 7, 2015)

It doesn't really have a set point. It's there to keep the fuel filter from icing over (soo warmish? Definitely not hot). Most of the heat put into the fuel is going to come from the engine, not the fuel filter heater.


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## Barry Allen (Apr 18, 2018)

Snipesy said:


> It doesn't really have a set point. It's there to keep the fuel filter from icing over (soo warmish? Definitely not hot). Most of the heat put into the fuel is going to come from the engine, not the fuel filter heater.


It's got to have a set point. It probably uses a PTC rubber heating element that is self-regulating, and when manufactured it has a set point that below that it's on (and heats up more the colder it is) to where it reaches the set point and it can't heat beyond that because of the self-regulating part. I haven't seen any schematics or diagrams so I honestly don't know what it is, but I'm still curious.

My thoughts are that GM probably aims for 40F so the initially cold fuel in the heater is heated above any potential remelt point of most diesel fuels, so wax is dissolved and passes through the filter.

And yes, long-term running means the fuel spill return from the engine adds heat to the fuel tank to where it might not need any filter heating. But in the absolute coldest climates the fuel flowing to the filter still might cool enough to need that filter heater.


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## boraz (Aug 29, 2013)

Barry Allen said:


> It's got to have a set point. It probably uses a PTC rubber heating element that is self-regulating, and when manufactured it has a set point that below that it's on (and heats up more the colder it is) to where it reaches the set point and it can't heat beyond that because of the self-regulating part. I haven't seen any schematics or diagrams so I honestly don't know what it is, but I'm still curious.
> 
> My thoughts are that GM probably aims for 40F so the initially cold fuel in the heater is heated above any potential remelt point of most diesel fuels, so wax is dissolved and passes through the filter.
> 
> And yes, long-term running means the fuel spill return from the engine adds heat to the fuel tank to where it might not need any filter heating. But in the absolute coldest climates the fuel flowing to the filter still might cool enough to need that filter heater.


only with garbage fuel


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## Snipesy (Dec 7, 2015)

Barry Allen said:


> It's got to have a set point. It probably uses a PTC rubber heating element that is self-regulating, and when manufactured it has a set point that below that it's on (and heats up more the colder it is) to where it reaches the set point and it can't heat beyond that because of the self-regulating part. I haven't seen any schematics or diagrams so I honestly don't know what it is, but I'm still curious.
> 
> My thoughts are that GM probably aims for 40F so the initially cold fuel in the heater is heated above any potential remelt point of most diesel fuels, so wax is dissolved and passes through the filter.
> 
> And yes, long-term running means the fuel spill return from the engine adds heat to the fuel tank to where it might not need any filter heating. But in the absolute coldest climates the fuel flowing to the filter still might cool enough to need that filter heater.



The set point is going to be for the heating element itself. Again 'warmish' I would say somewhere between 100F and 150F is when it would cut out. What that makes the fuel is a different story. And remember the cut out isn't exactly linear. More than likely its going to linger at something below that, especially on a cold day.


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## Barry Allen (Apr 18, 2018)

boraz said:


> only with garbage fuel


I'm sure, but manufacturers have to plan for some of the bad. You can blame customers for buying bad fuel but the PR from that becomes "GM builds diesel engines that gel up in winter!" and then it looks bad for you.

I doubt I'll have any problems with my car. I've got a local source that is B11 fuel or lower, and I'm sure they let the biodiesel content slide a little lower in winter. Minnesota has been pumping B5 for years without problems.

I'm still just curious and want to learn new things.


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## boraz (Aug 29, 2013)

Barry Allen said:


> I'm sure, but manufacturers have to plan for some of the bad. You can blame customers for buying bad fuel but the PR from that becomes "GM builds diesel engines that gel up in winter!" and then it looks bad for you.
> 
> I doubt I'll have any problems with my car. I've got a local source that is B11 fuel or lower, and I'm sure they let the biodiesel content slide a little lower in winter. Minnesota has been pumping B5 for years without problems.
> 
> I'm still just curious and want to learn new things.


my gen1 starts unplugged with fuel from the pump at -51f


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## Barry Allen (Apr 18, 2018)

boraz said:


> my gen1 starts unplugged with fuel from the pump at -51f


At that temperature it's pretty much kerosene coming out of the fuel pumps?


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## snowwy66 (Nov 5, 2017)

Barry Allen said:


> I'm sure, but manufacturers have to plan for some of the bad. You can blame customers for buying bad fuel but the PR from that becomes "GM builds diesel engines that gel up in winter!" and then it looks bad for you.
> 
> I doubt I'll have any problems with my car. I've got a local source that is B11 fuel or lower, and I'm sure they let the biodiesel content slide a little lower in winter. Minnesota has been pumping B5 for years without problems.
> 
> I'm still just curious and want to learn new things.


GM just builds the cars. They have no control over fuel gel. They don't produce the fuel. 

It don't matter what car one has. It's all about the fuel. Vehicle manufacture has no control over fuel quality. 

Biofuel can have a gel point of 45 degrees. Possibly even higher. All depends on what is being used to produce. 

I used to haul the stuff to Los Angeles. It was hauled in heated tankers. Tankers were plumbed in to the truck cooling system. The truck heated the tank via truck coolant. An extra 15 gallons of antifreeze was required. The heated tankers were hauling loads in temps down to MINUS 20. But the product stayed at 125 degrees. 

Samples were carried in little jars and had to stay inside the truck. 

Los Angeles doesn't get cold so they can sell bio year round. They were also small shops and only sold to local truckers. You wouldn't find any long hauls stopping in.


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