Reader’s Digest version:
Know your fuel.
Reduce effects of moisture by keeping tank full. Consider a water separator.
Use additives to reduce the cold filter plugging point.
Keep spare fuel filters in the trunk.


Long winded explanation: There are three fuel temperatures to deal with: pour point, cold filter plugging point, and cloud point.

Cloud Point (CP) is when the paraffin (wax) in the fuel begins to solidify (gel). CP is a constant for a particular batch of fuel and you can only control it by mixing with a batch that has a different CP. Additives will not change the CP. You either mix your own fuel or trust the fuel station to do it right. It’s the size and shape of the wax crystals that get you in trouble. You might feel a lack of power as the filter starts to plug.

Cold Filter Plugging Point (CFPP) can be a few degrees colder than the CP, depending on the refinery base stock and refining methods. An engine will start and run when you’re near the CFPP, but it will feel like it has no power (it doesn’t because the filter is beginning to plug up). Recall that you can’t change the CP, so in simple terms the additives lower the CFPP by reducing the size and shape of the wax crystals before they form. Additive won’t change the size or shape of the crystals in the filter (edit: after the crystals have formed). If you don’t want problems then the additive needs to be circulated through the complete fuel system before the CP is reached. Smart people immediately dose up the additive and change the filter when they sense a lack of power, then get some #1 in the tank ASAP to lower the CP, then check for moisture. Then they rethink their fuel and additive methods.

Pour Point (PP) is the freezing point of the fuel. Usually the fuel lines freeze first when you shut down for the night, then the filter. Symptoms are a no start, or a start with a shut down within a minute or so followed by a no start. Only fix for frozen fuel lines is to bring the vehicle into a heated garage and thaw them out. Was it fuel or water that froze?

Last comment: Your rubber fuel lines, injector pump, and injectors will thank you if you don’t use alcohol. Check the additive bottle label.

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daBenz - 1970 220D

The only thing I can add is to buy you fuel at a high volume station that has lots of truck customers. They will throw fits if the fuel gells on them, so keep their fuel in proper condition.

Always use additive in the winter -- around here, the temp can drop 40 degrees in a day once in a while, bad to have a full tank of waxy fuel and no additive in it.

Other than the occasional cold snap freezing the fuel in the car, I've not had any trouble.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I always try to keep a full tank of diesel in my car on top of using the additives.

I NEVER let my tank get below 1/4 in the winter. I use Redline DFC all year round and in the winter hit it with a glug of PowerService. It gets cold up here in NJ and I haven't had a problem yet.

JCD

I've been using the Power Service in the silver bottle when it's warm, and the white bottle in the winter.
Good points.
The station I've been buying from has a fleet of diesel tow vehicles, so I can pretty well trust their fuel not to be bad.

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Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic