Engine Sludge – When Good Oil Goes Bad

FOR people buying a used car, there is a very important but rarely checked factor to consider that goes beyond kicking the tires: original sin.

Some best-selling models appear to have an increased risk of serious mechanical problems, particularly if scheduled oil changes were not made during the vehicle’s formative years. The threat is the buildup of sludge — gooey tarlike deposits — that reduces or shuts off oil circulation and can mean thousands of dollars to repair or replace an engine that has seized.

Sludge is a thickening and breakdown of the oil as it deteriorates, as moisture and contaminants build up. This causes the oil to gel, resulting in excess wear as friction increases or, in extreme cases, a stop-right-now failure.

Worse, experts warn that there is no foolproof way subsequent owners of a trouble-prone vehicle can protect themselves. And if there is a problem caused by sludge, an automaker may reject a warranty claim because the new owner may not be able to prove that previous owners made the required oil changes.

Click here to read the full article from The New York Times.