Q: A smell is entering the cabin of our truck when we are sitting at a stop light, stop sign, in our driveway, or when fresh air is entering (as opposed to having the re-circulate button pushed in). The smell wasn’t noticed until after an oil change and the dealer said there were no leaks anywhere and the oil level is fine. Would you have an explanation for this?
A: One possible explanation may be that during the oil change, oil was spilled on the exhaust manifold or engine block. Now the oil is burning off when the engine gets hot and is releasing that smell. Inspect the area around the oil fill cap for any oil that may have spilled when the technician added oil to the engine. Another possibility is that when the technician replaced the oil filter the old oil filter gasket stuck to the engine block. Then when the new filter was installed, the two stacked gaskets cause the oil the leak. The oil could be leaking on the exhaust and burning off. Look around the oil filter for signs of leakage. Also check to make sure the oil plug is tight.