What you need to know about drain intervals for heavy duty

Should you have encountered a heavy duty customer querying how often to make an oil change, knowing how to address their question precisely can be difficult. 

Factors going into the oil change calculus depend on some competing factors. The days where heavy duty oil draining required doing every 8,000 km or so are gone. With engine and lubricant standards continually rising, there are some factors to consider when providing your customer with the right information. The right answer can vary

 between every 10,000 km to as much as 80,000-100,000 km. 

Important: Drain interval is detailed in kilometres or months! Have the oil replaced after, for instance, 24 months, even if you haven’t reached the maximum amount of kilometres.

Telling the ideal drain interval for heavy duty

Factors to consider include:

• Engine type and age
• Service conditions (haul and load)
• Oil quality 
• Fuel quality and consumption
• Road conditions (hilly or flat)
• …and many others.

From the start: Know your customer and their vehicle.

The drain interval for each manufacturer is determined through extended field-testing, statistical data and experience. With service bulletins, the intervals referred to are for standardised conditions. 

Really, in many instances, the recommended drain will need to be adapted in accordance with some important factors. 

Draw a baseline before taking into account all the factors. Possibly consider the engine type and its age. A good rule is to realise that the older the engine, the greater the chance of engine contaminants, which shortens the intervals between necessary oil changes. There is a need to examine your customer’s oil change methods.

Consider that these points may decrease the time required between changes of oil:

• Are they purchasing high-quality oil and filtration?
  • Low quality = shorter intervals
• How contaminated is the oil when it comes out?
• How are those pistons getting on? 
  • Lots of combustion zone wear indicates a requirement for more frequent oil changes
• How often is their need to top up?
  • Low fuel economy and oil efficiency provides a good indication of a requirement to change more often
• Smog test?
  • An increased level of tailpipe emissions provides a further concrete indicator for frequent oil changes

How driving conditions influence drain intervals

Driving in extreme temperatures or on dirty, dusty roads puts higher stress on the oil and shortens the oil drain. Long distance heavy-duty vehicles may reach a drain of up to 100,000 km while the more demanding short-haul operations typical for city transport will need a shorter drain interval. 

A driver needs to remember that the conditions matter, much like a sports coach knows that the weather influences his team’s performance. 

• Consider the amount of cold starts.
  • At engine start, low temperatures put a heavy strain on lubricants.
• Take into account hot weather.
  • High ambient temperatures affect the life of the oil.
• Where are they driving?
  • Accumulation of dirt isn’t just from contaminants within the engine. The quality of the road surfaces needs to be accounted for as well.
• Other factors at play
  • How hilly is the route? Are the loads heavy or light?

The big message is that the harder your engine works, the more strain the oil undergoes. If the strain is higher, the oil drain interval will be shorter.

Working it out:

It’s impossible to weigh all the ingredients going into the oil drain precisely, but it is essential to stress the choice of oil quality to customers. 

You aren’t without help, of course. For heavy duty fleets or large industrial equipment, a used oil analysis is possible. Chemical (base number, additive content, etc.) and physical tests (viscosity) can indicate whether the oil contains any usable life.

Finally, better oil increases the period between full oil drains. Choosing the right product means you don’t have to always work out the oil drain math. Manufacturers like Champion are tirelessly working towards a longer oil drain interval. 

It does remain crucial to check manufacturers’ documentation before you try and extend the oil drain using the information above. 

Summary:

• The drain interval is decided by each vehicle manufacturer.
• There are usually several factors that influence that recommended interval, however.
• You can analyse used oil in heavy duty fleets or large industrial equipment to assess its quality.