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Cold Weather Diesel Opearation
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Q: In cool and cold weather, my voltmeter jumps up and down. Is a belt slipping?

Intake Manifold Temp 
Pre-Heat Cycle Time Ignition on, Engine Not Running 
Post-Heat Cycle Ignition On, Engine Running 
Above 59 F (15 C) 
0 Seconds (no heat) 
15 F to 59 F (-10 C to 15 C) 
10 Seconds 
0 F to 15 F (-18 C to -10 C) 
15 Seconds 
Below 0 F (-18 C) /td> 
30 Seconds 

Q: Will the diesel start in subzero weather?

Q: Why Can't I use ether as a cold weather starting aid? Q: Should an additive be used in the fuel to keep it from clogging the fuel system? Q: How can I tell when the fuel begins to gell? Q: What can I do if the fuel has already gelled due to the cold?
Cold Weather Hints

From a 1995 issue of the Star Center News

By following the cold weather operating procedures in the Owners Manual, you will be able to reduce white smoke, improve cold weather starting performance, and maximize fuel burn efficiency in the combustion chamber.

The engine block heater usage is recommended as follows:

1) With temperatures above 40 deg F, the block heater is not needed.

2) With temperatures between 40 deg F and 0 deg F, the block heater is suggested.

3) With temperatures below 0 deg F, the block heater is required.

From:          Drdonnelly <>
To:              ramtruck

when it gets really cold and you can't plug in, cycle the grid heater twice.

Warming up a diesel is funny.  When the air is really cold, it hardly heats enough to burn the fuel that is injected.  Letting it sit and idle only makes it worse, as the chamber temp does not rise much.  Most of the fuel energy does work (runs the engine), and the poor thing can't warm up.  You gotta load it some to get some waste heat in the exhaust and water jackets.  However, you can't load it too much because it can't burn all that fuel, and you just wash the cylinder walls and puke out white smoke (unburned fuel).

I start mine, let it run maybe 30 seconds to get oil pressure and then a bit of time after the gauge comes up.  Then I drive gently for a bit--downhill grade is OK.  Just get a bit of time on it with very light load--moving the truck gently is enough.  After a couple to several minutes when it is just beginning to know it is running, put on a little more load...climb a hill taking it kinda easy, or something.  I try to keep egt down to say 600 max at this point (in the manifold).  Pretty soon, the water temp gauge will budge and your battle is over.  The giant has awakened and is ready for work.

Now I know the above is "extreme" babying of the engine in a way.  But, it works and is as close to optimum as I can come up with in the real world.  One thing is for sure--don't start it and idle for 5 minutes at the house.  That will clog the catalytic converter and coke up the injectors because the fuel can't flash off them completely.  You're much better off loading it just enough to keep egt at or just above 300 degrees.

As for the aftercooler, partially blocking the radiator does little to help when the thermostat is closed, but it will help the engine get warmer air in the cylinders.  The intercooler (really an aftercoooler) will only cool the intake air too much at this point if you don't partially block it when the engine is frigid.


Subject:   Re: DiRT: Cummins Winter Prep Questions
From:      "Rod Snaith" <>
To:          DiRT

>  do you find that the Ram keeps everyone's toes warm
> when running down the highway in sub-zero stuff?  Or does anyone put
> any type of cover over the radiator to up the temp a bit?

Always use a winter front when traveling in the cold...  Gas, diesel or whatever...  It doesn't take long for fuel lines to gel...  I'm not sure what its like in the US, but in Canada, the gas stations will switch to a winter blend of Diesel to prevent gelling...  I believe that the switch occurs as soon as temps start dropping to < 32F...  Carry a bottle of diesel anti-gel with you (but check to see what Cummins recommends)..  You may want to make sure and run down your tank of diesel that you've bought in warmer climates (once again this comes from sheer ignorance of how things work in your home area), and fill up once you hit the snow belt...




Last Update: May 3, 2001