Depends on the machine temperature/ambient temperature, all varies on the season & if the machine is left in the "paddock" or shedded:
- used in heavy applications close to start up our large farm tractor,pump or earthmovers, trucks & combines in Spring c.10minutes+ & longer in Winter (basically left after start up to fast idle until registering operating temp & while it's greased)
- a small tractor below 50hp usually warms in c. 5minutes
The critical factors are after initial start up not to let them idle too long below "fast idle" & let the engine reach operating temperature before using higher rev's or imposing high torque loads/power demands (including hydraulics/hydrostatic loads) otherwise glazing, premature wear or catastrophic failure may result
Adding to my previous post:-
- When the engine was last used & if it used sporadically/seasonally also has a major potential impact on engine wear/warm up time, for example if the engine has been sitting for month(s) the oil is not going to be as evenly distributed from start up as if the engine is used daily or even weekly.
- As for cool down period prior to shut off, Turbo or not we idle down for c.2 minutes, with most of our larger gear have turbo timers fitted set to idle/auto shut down after 2minutes standing (though they have coolled down already to an extent from travelling from field work)
- The quality/condition of the oil & coolants used, together with the condition of the machines cooling system will have similar influences on the wear/longevity of the engine to warm up/cool down time
Using these basic guidelines our larger gear regularly achieves 12000hrs+ with relatively clean oil sample analysis/little or no discernable engine wear. And even our CUT engine are ok @ 7000hrs+.
As we run our farms on "green" sustainability principles & on some have also secured organic certifcation, I always find the environmental aspects of our operations interesting considerations,though a holistic view of product "whole of life" cycle is required to fully appreciate environmental impacts,IMO:
- The extra diesel usage cost/emissions in warm up/cool down time is more than offset by the decreased engine wear/increased life of the machine, thereby avoiding the significant pollutants/resource consumption of producing a replacement machine....sustaining an older machine is generally more environmentally sympathetic than raplcing with new
- Though tempted by significant savings (@c.$17K+/yr) by Biofuels (diesel & ethanol) across our fleet, being hygroscopic biofuels readily absorb water, contaminates & promote the growth of diesel algae potentially inducing similar/greater engine wear characteristics to lack of warm up/cool down time. Also biofuels whilst offering advantages in CO2 emissions, are contrary to our "green" sustainable farming principles; with biofuel crop production (being high water & phosphate/nitrogen fertiliser dependent) when combined with biofuel production/refining have far greater overall environmental impacts than fossil fuels....others may have a different view.