LO 10-8 Describe the purpose of scheduled oil sampling and outline the steps to properly obtain an oil sample

1. Scheduled Oil Sampling

Scheduled Oil Sampling

Oil quality sensors, which are electrical devices that measure the amount of soot loading in engine oil, are now available to measure the condition of lubrication oil but are not mature in terms of the technological sophistication needed to perform condition-based oil changes. Still, such a sensor can help alert the operator when oil quality falls outside specified parameters as a result of the oil exceeding its useful life or a symptom of an engine problem. Additionally, one of several sensor technologies accurately measures soot, which thickens oil viscosity, absorbs oil additives, and contributes to engine wear. The sensor operates like a variable capacitor, using oil as the dielectric element. By measuring alternating current (AC) conductivity across the sensor at frequencies of 2–5 MHz, the sensor evaluates the dielectric strength of oil. This variable changes in proportion to oil quality.

In the absence of any sensor capable of comprehensively measuring oil quality, scheduled oil sampling (SOS) is recommended. In SOS, a sample of engine oil is obtained from the engine and sent out for analysis Figure 56,Figure 57 and Figure 58. SOS can provide extremely detailed analysis of the condition of the engine and the quality of the engine oil TABLE 10-8.

FIGURE 10-56: A clean, representative sample of oil is removed for analysis. During scheduled oil sampling, oil can be removed from the oil pan or engine oil gallery.

FIGURE 10-57: A scheduled oil sampling bottle is mailed for analysis. Results are available through reports accessed on the Internet.

FIGURE 10-58: An oil sample bottle can collect a sample of filtered oil from a running engine using a Schrader valve located in the engine oil gallery.