2004 Chevrolet Trailblazer LT 6 Cyl 4.20L
When I turn my 2004 Chevy trailblazer on it makes a thud in the engine area. Is that a bad thing?
It only makes the thud when I turn it on. It's been happening for two months now.
Any abnormal noise cannot be a good thing. Try to locate the source of the noise. Raise the hood, then let someone start the vehicle while you observe the engine and locate the source of the noise. This would be a first step.