fuel heater and #2 fuel gelling point

[cmills]

Is there a fuel heater on the fuel filter up on the engine? I know the heater on the rear one on my truck is not activated and was just wondering about the front one. And what is the temp at which #2 fuel gels, because a few weeks ago we were traveling through Montana and the temp was about 10 below and not paying attention I filled up with #2 instead of #1 fuel and didnt think about it til a few hrs later, the truck seemed to do fine with no problems, which really surprised me because I would have thought it would have gelled up at that temp.

 

[leaky gasket]

I Belive the gel point of untreated ULSD # 2diesel is about actually at -10°F. Depending on the quality of fuel and a few other variables I'm sure. Before ULSD diesel #2 if memory serves right I'm thinking the gel points were anywhere from 17 to 10°F.

 

[LocoPilot750]

Straight #2 clouds at 8 degrees above. Treated or blended fuel in my area (eastern KS) is good for -10. The clouded fuel is still liquid, but the new 5 micron filters strain that out (wax crystals) and becomes plugged if the rear heater is not working. The front heater should also have a heater to warm what is in the line forward of the rear heater. I think that is why my new truck made it about three miles before it quit running. The front heater was working, the rear was not.

 

[AH64ID]

Depending on the quality of #2 it can start to cloud in the 30's, but it's not common. The fuel heater's operate anytime the fuel is below 45°±8° and shuts off when the fuel reaches 75°±8° (at least those are the temp my 05 OEM and aftermarket Fleetguard heater use).

With a warm engine and warm fuel in the tank you were able to heat the fuel before it was an issue. If you had parked overnight you could have had issues.

ULSD does have a harder time recovering from waxing than LSD, it takes a higher temp for longer.

 

[Kirwin]

The North American specification for #2 diesel fuel cloud point (CP) is 15 F. However when the fuel reaches Cold Filter Plug Point (CFPP) is when your SOL. This temperature is some amount below the cloud point and is the temperature at which the wax particles that form in the fuel are larger that the "holes" in the filter medium. Obviously the filter medium is a factor in this. From our experience here on the TDR this point is somewhere below 0 but above -10 F for normal non winterized #2 diesel. As was pointed out by someone else here on the TDR, we can call it gelling, or what ever we want, but the clogged fuel filter is what brings us to a halt. A diesel engine that can't get fuel will not run! Keeping the fuel filter warm allows these wax crystals to melt so they don't plug the filter. Ken Irwin

 

[cmills]

This may be a dumb question but will the wax that builds up on the fuel filters melt once the temperature warms back up above the the "gelling temp"? (I'm assuming it does) I'm just curious because since it was so close to that point when I was driving it makes me wonder if it might of actually started building up on my fuel filters. So, I guess if it does melt once it warms back up then I'm fine but if not, I wonder if I should just change my fuel filters just in case there is some of the wax built up on them. once again, sorry for the dumb question.

 

[Kirwin]

It dissolves back into solution at a higher temperature. How warm the bulk fuel has to get is debatable. However the fuel filters are not at the same temperature as the fuel in the tank. So it can take a significantly warm temperature to get the fuel to "dissolve". Ken Irwin

 

[AH64ID]

Yes it will, once the fuel warms back up its normal again.

 

[cmills]

Well I guess I am fine then because it has been up in the upper 40's a few times since then and I have ran a couple of tanks of fuel through it. I guess that saves me changing $100 in fuel filters for nothing also but I just wanted to be sure everything was good. Thanks for the help.

 

[Ozymandias]

Also the Fuel in your Tank isn't cold when you drive, because of the return Flow the whole Diesel heats up pretty much.
Touch it with your hand after a 2 hour drive and you'll fell how warm it is.

 

[mfurrh55]

I've driven in Utah when the temp. was -27 and never added any treatment to my fuel and never had any problems with gelling, i'm guessing the station in Vernal,Ut. where i filled up , had plenty of treatment in their fuel

 

[cmills]

Also the Fuel in your Tank isn't cold when you drive, because of the return Flow the whole Diesel heats up pretty much.
Touch it with your hand after a 2 hour drive and you'll fell how warm it is.

That makes sense too because we had been driving for hrs. I'm just glad I don't need to change the fuel filters already with only 3000 miles on the truck.

 

[cmills]

I guess it only makes sense that the wax would melt out of the filters because if it didn't anytime you had an issue with gelling you would have a tank and fuel lines full of wax afterwards. I guess I just wanted to make sure there was no negative effect on the filters.