What is Sludge?
There are different “types” of sludge, they are of different appearance ranging from light brown to opaque black, they range from semi-liquid to solid, and they can be formed by different chemical reactions. Since any sludge is formed primarily from the engine oil, the oil itself appears to be at fault. Actually the oil is the victim of mechanical and chemical attack. The formation of sludge is a very complex interaction of components which include mechanical and thermal stress and multitude of chemical reactions. Although there are thousands of documented engine failures in the field, not a single research chemist has to date succeeded to create a “synthetic” sludge under controlled laboratory conditions. The real life conditions are therefore so complex as to be virtually impossible to duplicate in laboratory, yet hundreds of engines all over the world fail daily due to sludge formation. While some engine types are more prone to sludge formation, the fact is that only very small prop
Sludge is a suspension of a solid matter in a liquid. There are many other terms that are used in place of sludge like wastewater solids and biosolids. The other terms are more specific to the process that generated them or to the usage category. Sludge is generic and can be applied to any solid/liquid by-product or waste.
Another rampant problem is sludge formation. Many manufacturers have turned to synthetic oils to fight the formation of sludge, requiring owners to use synthetics meeting manufacturers stringent specifications due to the contamination, high oil temperatures, extended drain intervals, small filter capacities, and reduced sump capacities. Visit http://en.wikipedia.org/wiki/Oil_sludge for a list of cars suffering sludge formation and you can see this is a big deal. Another excellent link on sludge formation is http://www.schleeter.com/oil-sludge.htm. Sludge formation in our older aircooled engines can easily be solved by getting the engine (and oil) sufficiently hot (>212F) and doing so for at least 20 or 30 minutes at a time. Try to avoid starting up the engine and just letting it idle, as this just increases the fuel contamination in the oil. You do more harm not getting the oil up to temperature and putting serious miles on it than not starting it at all. Changing your oil after the ca
