Q & A

Antifreeze in Oil

“We recently received an oil sample report from our lab indicating a coolant leak, even though the results for the FTIR test for glycol came back negative. Is the lab wrong or is there something I’m not understanding here?”

Laboratory tests for glycol, which include both FTIR and Schiff’s reagent, are designed to measure the presence of glycol molecules in an oil sample. However, depending on where and how the glycol is entering the engine, it may burn before it even reaches the oil. Since combustion will destroy the glycol, any chemical test for its presence will be negative, even though a serious coolant leak may be present.

Most labs are aware of this problem and do not rely solely on the presence (or absence) of glycol to warn of potential coolant leaks. Instead, they take advantage of the characteristic “elemental fingerprint” of common inhibitors that are used in engine coolant. These inhibitors typically include, sodium, potassium or boron containing molecules. Since most crankcase engine oils do not contain sodium or potassium (though many do contain boron), the presence of either of these in an oil sample may indicate a coolant leak.

Today's Tip

• Clearance sized particles can have the following effects on valves in hydraulic systems:

• Surface erosion

• Solenoid burnout

• Spool jamming/silt lock/stiction

• Slow response/instability
  

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Book Bits

"Oxidation drastically affects the quality of a fluid. The following conditions promote the oxidation process:

• Presence of oxygen (aeration)

• Mechanical agitation

• High pressure

• High temperature

• Catalysts (water and metal particles)

Metals and various mechanical impurities act as catalysts in accelerating oxidation. The smaller the particle, the greater the surface area represented in the population and the more effective the catalyst."

For more information about the book "Fluid Contamination Control" go to:

http://www.noria.com/secure/product_detail.asp?catalogid=47

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