Mechanic failed to replace heat shields

I had my exhaust system repaired. I later checked the pipes due to a burning oil smell, and saw that the heat shields in front of, and under my engine had not been put back. Any oil drip would now burn and smell.

How critical are these heat shields? Should I demand a replacement, and not pay for the repair? Or am I being unreasonable.

The heat shields are there for a reason. They protect the underbody from the intense heat of certain exhaust system components, such as the catalytic converters. If the heat shields are removed, there is a potential for the metal floor of the car to overheat, and then the padding under the carpet can overheat, too. You can see where this is going, can’t you?

I would go back and ask to have the heat shields reinstalled. They were taken off, they should have been put back on.

heat shields in front of, and under my engine

Are you sure there were heat shields under the engine? The ones I would worry about are the ones under the cabin and trunk area.

Absolutely replace them! My brother-in-law had a mid-size Ford, which had honeycomb converters, and due to poor spark plug maintenance, the converter turned into an afterburner combusting the unburned fuel. The result was, as previous poster mentioned, that the carpets caught fire, and the whole car was nearly destroyed. Also a good reason for keeping your engine in tune.