ETHYLENE GLYCOL IN USED ENGINE OIL: ASTM D4291
EXPLANATION
Leakage of aqueous engine coolant into the crank case weakens the ability of the oil to lubricate. If ethylene glycol is present, it promotes varnish and deposit formation. This test method provides for early detection to prevent coolant from accumulating and seriously damaging the engine. This test method is valid in the range 5 to 200 mass ppm of ethylene glycol.
Another procedure, Test Method ASTM D2982, is also used for the determination of glycol antifreeze in used lube oils.
TEST SUMMARY
The sample of oil is extracted with water and the analysis is performed on the water extract which is injected into a gas chromatograph using on-column injection. The eluting compounds are detected by a flame ionization detector. The ethylene glycol peak area is determined and compared with areas obtained from injecting freshly prepared known standards.
TEST PRECISION
This test method has a repeatability of 0.212X and a reproducibility of 0.528X where X is ethylene glycol content in mass ppm.
The bias of this test method has not been determined.
