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Motor Vehicle Maintenance & Repair

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What does exhaust smell on oil and transmission dipstick mean?

14

I was inspecting a used car and the oil and the transmission dipstick smelled of exhaust (carbon monoxide?). What does this mean? Does it mean that the engine's gone bad and I should stay away from that car?

2 Answers

4

Smelling AT fluid is (or did ) give a good hint of the transmission general condition , but it requires experience. The clutches and bands have material like brake pads and if they slip, they heat very quickly although running in oil , and have a "burned" smell.

3

If the motor oil has a distinct smell of exhaust fumes, it might also mean that the cylinder head gasket has become leaky. Transmission fluid should never smell of exhaust gases, but can get a certain burnt smell from the clutch pads.

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What does exhaust smell on oil and transmission dipstick mean?

14

I was inspecting a used car and the oil and the transmission dipstick smelled of exhaust (carbon monoxide?). What does this mean? Does it mean that the engine's gone bad and I should stay away from that car?

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9

Smelling AT fluid is (or did ) give a good hint of the transmission general condition , but it requires experience. The clutches and bands have material like brake pads and if they slip, they heat very quickly although running in oil , and have a "burned" smell.

edit

Well, it comes from experience of working on cars and knowing what causes what when you have particular smells. It probably isn't going to work for the OP though since they thought they were smelling Carbon Monoxide. - Nelson Oct 18, 2019 at 10:13

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