Foam in oil consists of the accumulation of small air bubbles at the surface of the lubricant. It is is caused by excessive agitation, inadequate levels of fuel, air leaks, contamination or cavitation.

The particle quantifier index test measures the mass of ferrous wear debris in a sample and displays this as PQ index by Hall Effect regardless the particle size. The Hall Effect is a measurable induced voltage across a sample. The higher the observed Hall voltage, the higher the concentration of ferromagnetic wear debris present.

As seen in our previous issue, synthetic esters are considered nontoxic and biodegradable. They offer an environmental friendly alternative to conventional mineral-based oils due to improved energy effectiveness, reduced part wear and biodegradability rate.

We often get questions on the difference between the various types of lubricating oils: mineral based, synthetic-based and bio-based oil. We will deal with mineral and bio based oils in subsequent issues. A symplistic explanation is that mineral oils are refined petroleum products whereas bio-based oils (most being vegetable oils), are extracted from various crops such as soya, corn, canola, etc. A fourth type of oil, namely re-refined oil is also considered as base oil. However, in this article will be focusing solely on synthetic oil.

In the previous issue of this Newsletter we have seen how total water hardness in coolants may lead to corrosivity due to to high calcium and magnesium content. Total hardness however, is just one test among many others for coolants.