Soot is mostly harmless until it starts to clump, so preventing clumps is essential. Once clumps begin to form, they'll impede oil flow and cause all sorts of problems within the engine.
Changing the oil at the manufacturer's recommended interval is the easiest way to help prevent soot buildup; after all, regular lube changes should be performed anyway. It's best to select high quality motor oil that's formulated with special dispersants to prevent those unwanted globs of soot from forming. Good diesel oil will also include ingredients to protect the engine's surfaces from soot abrasion. Just remember to follow the manufacturer's recommendations for proper weight (also known as viscosity -- the industry standard that describes the oil's properties for flow and surface lubrication).
It's especially important to pay attention to motor oil requirements for newer diesel engines. They're designed to reduce harmful emissions for a lower impact on the environment, so they have higher injection pressure than the diesels of the past. This means the engines' internal surfaces are more likely to suffer abrasion damage by soot and other contaminants. Circulating soot also scrubs off protective coatings and lubricants, which can cause an increase in seizures within the engine.
Even regular oil changes have to be accompanied by other preventative procedures. The only other method to prevent soot buildup is to keep the engine in good shape -- though that's a process comprised of many factors. Soot buildup can be caused by:
- Poor timing
- Too much idling
- Improper air-fuel ratio (either improperly calibrated, or as a result of the fuel nozzles spraying the incorrect amount or pattern of fuel)
- Worn out or dirty air filters
- Excessive ring clearance
These problems all affect the proper mixture and efficiency of fuel being burned. This results in soot buildup, which in turn makes the problems even worse. Fortunately, this cause-and-effect cycle can usually be identified early by symptoms that affect the car's drivability. Pay attention to stumbling, stalling, misfiring and hesitation, all of which indicate potential engine efficiency problems. These problems all require repair or replacement to restore proper combustion, improve engine efficiency and restore overall drivability.
If you're looking for more information about ways to prevent soot buildup in engines, follow the link below.
- Amsoil. "The Harmful Effects of Engine Soot." (June 6, 2011) http://www.performanceoiltechnology.com/engine_soot.htm
- BASF.com. "CSF - Catalyzed Soot Filters." (June 6, 2011) http://www.basf.com/group/corporate/en/brand/CSF_CATALYZED_SOOT_FILTERS
- Diesel World. "Soot Patrol." Nov. 2, 2009. (June 6, 2011) http://www.motortopia.com/dieselworld/uncategorized/soot-patrol-366/
- Fitch, Jim. "Four Lethal Diesel Engine Oil Contaminants." Machinery Lubrication. June 2007. (June 6, 2011) http://www.machinerylubrication.com/Read/1033/diesel-engine-oil-contaminants