The 2000 Jeep Cherokee I recently purchased with almost 232,000 kilometres on it clearly did not receive proper maintenance. After the replacement of a leaky valve cover gasket, my mechanic indicated that it was super gunked up. He suggested an engine flush and a fresh oil change. The reviews I've read state that engine flushes are a bad idea and can cause extensive damage to your engine. – Beth D.
Yes, your Cherokee's power plant is exhibiting excessive sludge buildup from a lack of oil changes, and an oil flush is a questionable solution, one that would possibly aggravate the situation.
As engine oil becomes severely contaminated, its viscosity migrates from that of a fluid into a solid, ceasing to flow, hardening into a solid-like mass commonly referred to as "sludge."
This build up occurs relatively slowly. Chemicals that cause rapid removal or loosening of that sludge may dislodge a large particle.
Oil manufacturers design products with additives intended to breakdown and suspend contaminants that can be safely delivered to the filtration system. When a large particle breaks off, the best we can hope for is that it gets caught by the filter, but it can also get lodged – blocking an important oil passage, ultimately causing engine failure.
I consider engine flushes to be periodic maintenance items intended for engines that are in relatively decent condition. I would ask your mechanic for a review of your situation. Since he is recommending this service, perhaps the sludge isn't as bad as initially thought, otherwise caution is in order.
Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing "Lou's Garage" in the subject area.
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