The Advantage of a Cold Start on your Diesel

Article 3 of a 3 part series.

Temperatures below the freezing mark make your diesel harder to start.  That’s not a surprise however it is much more complex than you might think.  Consider this…the ambient air temperature and air pressure decrease your battery power and increase oil viscosity which can lead to increased engine friction.   This also impacts starter speed and compression ratio.  Combine these circumstances with the efficiency of the injectors, your fuel cetane and fuel fluidity which leads to a higher torque demand on the engine and a lower starting speed.  This complex series of events may or may not lead to a successful ignition and start.

One of the advantages of cold weather is that it reveals weaknesses that your engine was experiencing during warm weather but the symptoms weren’t dramatic enough to notice.  Most often, those symptoms are lower MPG that directly impacted your wallet.

For example, when the temperature is above 40 degrees your diesel’s engine oil is thin and runny.  If the injectors are not firing at maximum efficiency due to stiction (sticky, gummy residue left by burnt oil) your engine may still start without hesitation even though stiction is negatively impacting MPG.

The first time it gets below 40 degrees the engine oil starts to thicken and gets gummy.  That injector with barely noticeable stiction now is experiencing increased hesitation.  The diesel becomes hard to start.  It shakes.  It rocks.  It doesn’t want to settle down. You pull out and there is no throttle response. No giddyup.  It takes 15 minutes to get up to 50 MPH.

The good news is that you very likely just diagnosed a stiction problem which can be quickly and easily resolved with one treatment of Hot Shot’s Secret Stiction Eliminator.  Add it with your oil change and give it 500 miles to work through the oil system.  Your smoke output may increase slightly during this period as the stiction is being removed and expelled via the exhaust.

Chris Gabrelcik is certified with STLE as a CLS and OMA.  He personally developed and tested a product designed to remove stiction called Hot Shot’s Secret Stiction Eliminator.