WK 08 CRD Winter Time Diesel Questions


TJ Enthusiast
Supporting Member
Sep 6, 2018

I purchased a 08 CRD WK. I live in Michigan and I am trying to understand a diesel engine and winter. Thank you in advance. Sorry this is all over the place.


Can you explain diesel fuel 'gelling'?
  • I have heard that diesel 'gels' in cold temperatures. Does it gel in the gas tank?
  • I also heard, it gel's when its injected into the cylinder and that is what causes the engine to not start.
  • I also heard that if it gel's, you should replace your fuel filter. If fuel gels when its injected, why would that mess up a fuel filter?
  • Glow plugs warm up the air in the cylinder correct? (because the fuel gels when injected into a cold space?)
  • Engine Block heaters, warm the oil in the engine. So is the thought that the warm oil heats up the cylinders enough to keep the fuel from gelling when its injected?
  • How do I know if my fuel has 'gelled'?
  • If it does 'gel' how to I ungel it?

Winter diesel at Michigan fuel stations add's additives that helps to prevent the fuel from gelling? Correct?
Do I need to add more additive to it?

At what temperatures do I need to worry about plugging in my engine block heater? Below what?

With a glow plug, do I actually need to plug it in at all? If it starts, is all good to go?

Last question: Is it harmful when it starts up rough (smoke, and the car bucks a bit).

Thank you!!!
Don't have a jeep diesel, but a ford. The diesel will gel in the fuel lines and filters. I carry spare filters. I also add an additive with every fill-up. My truck sits for days or weeks, bit I've never plugged in the block heater. I've read the owners manual, and I think the block heater is only necessary if the temps are well below 0.

This is the stuff I use, but there's a lot out there.