Tom's Corner Garage: Avoiding Engine Sludge

This weekly feature for Edmunds Daily about car repair and maintenance is written by Tom Torbjornsen, the popular host of America's Car Show on satellite radio.

Dear Tom,
I own a 2000 Lexus ES 300 Platinum Series.  I purchased it about three years ago, and at the time it had only 4,400 miles on it. It now has nearly 39,000 miles. It seems to be running fine and the Lexus dealership has never indicated any problems when I get the car serviced. However, I wonder whether there might be sludge buildup because the car sat idle in its early years (only 4400 miles driven by previous owners over a 6-year period). Could this be a problem later on? And would it be evident by now?
Michael from Long Island, NY

Contrary to Michael's concern, sludge does not set up as a result of an engine that is rarely used. It occurs due to extensive engine use in an environment where the engine is not maintained (infrequent or no oil changes).

What is sludge and how does it form?
Sludge is a nasty, gross, hardened buildup of oxidized oil that forms as a result of not changing your oil (according to manufacturer specs). Old oil that doesn't lubricate well causes an increase in friction between engine parts and thus the engine temps increase. When sludge sets up inside the engine, it builds on itself and inhibits the flow of oil, causing even more problems with internal lubrication. The result? Premature wear and, ultimately, premature engine failure.

How do I stop sludge buildup in my engine?
You can control sludge buildup by maintaining a vigorous maintenance schedule according to the service schedule in your owner's manual.

Years ago sludge was a common occurrence caused by inferior engine oils that lacked the detergents of today's oils. Back in 1974 a customer of mine, Sheldon, owned a '66 Mercury Comet Caliente' with a 289 V8 engine. He drove the car 200 miles a day, five days a week for his work, so he maintained the car according to the severe service schedule.

When I met Sheldon the car had 120,000 miles on it and the engine had never been opened up. This was unheard of back then. Most cars at 50,000 miles had at least the cylinder heads removed and a valve job done. I observed Sheldon meticulously maintain his Comet. Every 1-2 months or 3,000 miles without fail, he brought the car in for an oil and filter change.

Sheldon had to eventually let the old car go because of body rust (with the engine still running like a clock). He donated it to me so I could perform an autopsy on the engine. I needed to know how and why he was able to log so many miles. Once opened up, the engine spilled its secrets. Internally, it was almost spotless. There was hardly any evidence of internal wear. Vigorous and diligent maintenance had cheated "engine death from sludge", the most common killer at that time. As a young impressionable mechanic I became a believer in vigorous maintenance.

Toyota warranty extension for sludge
After some research I found out that Toyota did have a sludging issue with the ES 300 and other models from this time period. Toyota had designed the restricted cooling system passages in an effort to meet stringent EPA tailpipe emissions standards. The restrictions caused an increase in engine operating temps and the high temps caused the sludge. Toyota did extend the warranty on these engines. If you own a Toyota product from this time frame, keep a watchful eye on the engine oil. If you find that your car is using excessive amounts of oil, contact your dealer. They might replace the engine under this extended warranty action from Toyota, providing you meet the criteria. The TSB (Technical Service Bulletin) number for this action is # TC02002. Also, check this link for further info.

All you have to do is plug in the year, make, and model of your vehicle. Don't put in a system option; that way you'll be able to find out all activity that was issued on your vehicle. Scroll down through the list to find the TSB for "Gelling," which is the term Toyota uses for engine sludge buildup.

'Til next time...Keep Rollin'

Posted by

Ron Montoya November 4, 2009, 1:00 PM

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