Dishing the Dirt on Engine Failure

FEDERAL-MOGUL talks about the key sources of contamination that cause engine damage and failure.

Moving engine components such as pistons, crankshafts, camshafts, bearings, valves, oil seals and pumps are susceptible of damage as a result of dirt abrasion. The reason is simple – where there is movement within the engine, dirt and impurities will cause abrasion and damage.

Normal engine wear and tear will cause some contamination as it produces small debris that is not all trapped by the oil filter. However its impact is miniscule in comparison to the three major causes of engine contaminants detailed below.


Dust and grit thrown up by car tyres can make their way into the engine compartment and sometimes into the engine. Whilst replacing the air filter at the scheduled service will remove most of it, some contaminants will still get through if connections are not thoroughly checked. Damaged trunking, as well as poorly connected air and oil filters to the engine will allow unfiltered air to bypass the filters that remove dirt as it is drawn into the engine.

Filters in the fuel, breathing and vacuum systems should also be checked in accordance with the vehicle manufacturers’ recommendations and schedule. Most damage caused by dirt entering the air intake or contaminated oil will be evident on the compression rings and upper ring lands. Piston skirt areas will experience less severe damage.


Sometimes contaminants are introduced into the engine during its assembly. This leads to abrasion on the back of the bearings as dirt particles are compressed between the crankshaft bearings and their housings. In time, this will also cause wear or abrasion on many other engine components.

Dirt left in the oil galleries will scratch or leave pockmarks on the crankshaft bearings. Furthermore, re-boring and crankshaft grinding debris can also contaminate the engine if not removed thoroughly.

Parts can even be contaminated by a dirty engine assembly bench as they are lubricated before assembly.


Dirty lubricating oil is another source of contamination. Oil kept in a bulk store, and carried to the engine in a dirty container, will contaminate the engine when used.

This will damage crankcase components and the lower portion of the pistons. The same sort of damage can also occur from “built-in” dirt, but only dirt trapped between the bearing and housing will prove that the oil wasn’t the problem.


Engine damage as a result of common causes of contamination can be prevented when technicians follow the following pointers:

  • Maintain a clean engine assembly bench
  • Remove re-boring and crankshaft grinding debris
  • Store and transport lubricating oil in clean containers
  • Adhere to recommended service schedules and procedures when replacing air and oil filters

Federal-Mogul serves the aftermarket with a portfolio of premium automotive parts from known brands like AE, Glyco and Goetze.

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Published on: April 13, 2020

Filled Under: Engine, Technical Articles

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