Monitors Could Combat Oil Sludge

Issue heats up at VW, Chrysler

By Richard Truett
Automotive News / September 06, 2004

DETROIT — An inexpensive device that checks the condition of engine oil and warns the driver when it's time for an oil change could help Volkswagen of America Inc. and the Chrysler group avoid future troubles with oil sludge.

Both companies have come under pressure after reports were published of engine failures caused by sludge buildup.

General Motors says about 95 percent of its 2005 models will come with an oil life monitor. GM says the device – a $10 sensor in the engine that measures the number of times the pistons fire and the temperature of the oil – has helped drivers avoid sludge problems.

Sludge clogs oil passageways in the cylinder block. These passageways, which are about the circumference of pipe cleaners, are like arteries.

Once the passages are clogged, moving parts such as valves, pistons and camshafts are starved of oil. They can seize, causing engine-destroying failures.

Similar sensors

Toyota and Chrysler offer oil sensors on a few of their most expensive vehicles, such as the Toyota Sienna minivan and the Jeep Grand Cherokee.

Chrysler spokesman Sam Locricchio said the automaker is considering offering oil life monitors on more nameplates.

Last month the Center for Auto Safety asked Chrysler to extend the engine warranty to 10 years and unlimited mileage on 2.7-liter V-6s used in a variety of vehicles. The center said there have been several cases in which sludge-filled engines seized in traffic.

VW last month sent a letter to 426,000 Passat and Audi A4 owners warning them of sludge problems with 1.8-liter turbocharged engines. VW is extending warranties from five years to eight years and is requiring dealerships to use synthetic motor oil and a larger oil filter.

VW does not offer an oil life monitor on vehicles and says it is not considering them.

Chrysler has evaluated about 400 warranty claims of sludge-filled 2.7-liter V-6 engines used in a variety of vehicles.

VW would not disclose how many complaints it has received, but a source at the National Highway Traffic Safety Administration said the agency has had 12 to 15 complaints.

Bob Orlee, a GM engine engineer who specializes in oil issues, said GM installed the monitors because many consumers did not read their owner manuals to learn when they should change their oil.

He also said some consumers didn't know that severe driving areas, such as those with high heat and heavy traffic, required them to change their oil more frequently.

He said synthetic oil likely won't prevent sludge buildup.

Confusion abounded

“We realized in research back then when we talked to customers that they had no idea if they were severe or moderate drivers,” he said. “Even with all those words we put in owners' manuals it was so difficult to describe to people when they should do an oil change. The oil life monitor simplified the maintenance procedure.”

GM began using oil life monitors in the 1980s.

Chrysler engineers say improper maintenance is the likely reason for sludge buildup in some vehicles. About 70 percent of the vehicles with sludge-filled engines were sold to rental car fleets before consumers bought them as used vehicles, Locricchio said.

“The second or third owner can change oil on time, but if the first owner didn't, the engine can be susceptible to sludge,” he said.

VW recommends oil changes at 5,000 miles or six months, or more frequently when climate or driving conditions are extreme.

Chrysler says owners should change oil every 3,000 miles in city driving or every 7,500 miles in highway driving.

Toyota Motor Sales U.S.A. Inc., which wrestled with a massive sludge problem in 2002 and 2003, denied there were design flaws in some of its four- and six-cylinder engines and blamed consumers for the problem. But Toyota ended up extending warranties, replacing engines for free and changing the oil breather system in valve covers.

Orlee, the GM engineer, said sludge always has been a problem for engines. But improvements to motor oil and engines have reduced problems.

Said Orlee: “Sludge has to do a lot with how you drive. Classic sludge was related to low-speed operations, like in taxicabs. Some of the sludge out there now we believe may be a different form of sludge. Some of it happens only in hot climates.”