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Lou, how necessary is it have a hot oil flush every 24k? I have a 2015 Mazda CX-5 and this has been recommended to me by a dealer. The cost of an oil change has more than doubled with this flush. I use synthetic oil and would like to understand the benefits. – Rick

You won’t find a “hot oil flush” mentioned anywhere in your factory owner’s manual and I doubt you will find any other official Mazda literature dealing with it. These aftermarket chemical services are left to the dealer’s discretion and are considered to be an up-sell item.

As with most turbocharged vehicles, your Mazda will suffer from sludge buildup. Preventing this sludge is the key to longevity for your turbocharger and engine. The dealer will have you believe that a scheduled oil flush is part of that prevention formula.

Unfortunately, I regularly observe owners who follow their maintenance guidelines reasonably well and perform the oil flushes, but still get saddled with sludge-related repairs. If you idle your car an excessive amount, are tardy with your oil changes or have purchased a used vehicle without a service history, then oil flushes have their value.

The effectiveness of this chemical procedure is often debated in our industry. One thing for sure is it is extremely hard to measure the value of this service for the careful owner.

Being extremely diligent with your oil change intervals and using quality products is the most effective solution.

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 line.

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