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lou's garage

I have a 2007 Mazda B2300 pickup. I smell burning oil through the ventilation system, but there is absolutely no sign of an oil leak under the hood. I have had two mechanics check it out thoroughly. They agree that the smell is there, but can’t find the source of it. The valve cover gasket is new. I am not losing any oil either. I have narrowed down the smell to left front area just behind the head light because that is the only place where the smell come from if I put my nose along the gap when hood is down. Your thoughts?

Narrinder J

Being able to smell something inside the truck and at the left front only is quite odd. I believe for the time being you should consider them as separate issues. A minor exhaust leak at the manifold will cause a smell that is easily confused with burning oil. Also, given the age of the truck I have to assume that it is not perfectly leak free. Even the most minor amount of leaking oil or coolant will cause a smell. Small sources can be exceptionally difficult to find as they may not be significant enough to drop to the ground, but will burn off while running down the side of a hot engine. A UV dye will help locate those pesky smaller leaks.

It is also possible that the smell within the truck cab is coming from the heater system itself? A heater core with even the slightest coolant leak will cause a smell within the cabin.


I saw your answer about winter wheels and tires packages and completely agree that it makes sense. I also agree about the TPM being fitted in the winter setup which I didn’t do and regretted it. What is the theory and benefit to downsizing to a smaller wheel when fitting a winter setup? Is it really necessary? – Steve M

It is not absolutely necessary, but there are benefits to using a smaller wheel size for your winter setup. First, using a smaller diameter wheel setup must lead to an adjustment in the tire size in order to keep the vehicle’s manufacturer specifications within a 3 per cent diameter variance. Also known as minus sizing, a notable immediate benefit is that the higher/taller profile tire offers superior deep snow traction. This is because the taller sidewall tire has greater flexibility which aids in clearing snow from the treads. Another huger benefit is cost saving. Anyone who is shopping should get a quote for both an original size package and a minus sized set. You will quickly see the difference in pricing.

That being said, minus sizing is not for everyone. A car with minus sized tire package on it will not handle quite as crisply or nimbly as it did with the original size on it. Some drivers that are completely in tune with every nuance of their driving experience may find this difficult to live with. In addition, cheaper steel winter wheels have a bad reputation for poor quality, causing irritating wobbles that never seem to go away.

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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