For those with diesels how low an outside temperature does it take before you start thinking about an additive? I know there are seasonal grades of fuel and I don't want to be blindsided with a fuel gel issue. TIA

I don't worry about it unless it gets to the low 20s or worse.

-38 in the pic above.

With 10% biodiesel fuel it gells at a higher temperature.
I've never been stopped but the engine stuttered around 18 degrees one time so I use 25 degrees as a guide and put an additive in when its getting that cold.

I use it when the temp falls below freezing. My 05 duramax gelled twice; Jan 2010 (Austin) and Jan 2018 (Houston), and it's no fun when you are away from the house. Both times, the truck did start, and I let it warm for a long period of time, but it seems its was the cold air from driving that did it.

In 2018, the darn truck died at the front gate of Camp Mabry and I was so embarrassed. The guards and I had had to push the truck, and it did not start until the sun warmed up a little. Perhaps it was bad fuel but it gelled twice, so I also use an additive when the temps fall below freezing.

15-20 degrees or so is the gel point, but this is a ball park. The other thing to keep in mind is even with an additive in the fuel a typical conventional diesel oil for around here will be like molasses when it’s that cold, so it’s gonna be angry for a minute during warmup when it’s really cold even if the diesel didn’t gel with an additive.

Any recommendations on additives would be appreciated.

Diesel gelling only occurs at very cold temperatures, below 10°F . If you’re experiencing issues at temperatures above 10° to 15°F, you’re likely dealing with an ice issue, rather than a gelling issue. Power Service with centane booster should cover you.

Usually prolong temps in the low 20's. Depending on what part of the country/state the fuel you get at the pump will either be the northern blend or not. The Northern blend Gels at much lower temps.

howes diesel treat, wal mart, auto supply, truck stop, great stuff and an anti gel.

sat in the semi in toronto canada for a weekend locked in a bonded yard, wind chill got to -50 both nights and daytime was never above -5.

cummins isx, 350 gal. total with 2 tanks, gallon of howes in ea. before I left detroit.


also remember there is a winter blend that should take you to about 0*, if you buy fuel at the same co. a lot ask what their mix is for winter/temp. it will handle.

yeah pro longed temps in low 20s is the only time I have had an issue. Even then it was just rough idle till it warmed up.

Course we only see that once every 3 years.

I’ve never had my fuel gel all the way down to single digits but truck will be rough for a couple of minutes when first started. I have run power service and Howes and probably other that I’ve forgot about.