Exhaust flange bolt size on 1999 Chevy S-10?

There's no single answer to the exhaust flange bolt size on a 1999 Chevy S-10. The size depends on several factors, including the engine size (4.3L V6 or 2.2L I4) and whether the exhaust system is stock or aftermarket. Even within the same engine, variations can exist depending on the specific manufacturing run.

To find the correct size:

* Visually inspect the bolts: The easiest method is to remove one bolt and measure it with a caliper or compare it to a bolt size chart. Note the thread pitch as well (e.g., 7/16"-14).

* Consult a repair manual: A Haynes or Chilton repair manual specific to your 1999 Chevy S-10 will list the bolt sizes for the exhaust system.

* Check online parts stores: Websites like AutoZone, Advance Auto Parts, or RockAuto allow you to search by vehicle year, make, model, and engine. When viewing diagrams of exhaust components, the bolt sizes are often specified.

Without knowing the specifics of your S-10's exhaust system, it's impossible to give you the exact bolt size. Always measure the existing bolts to ensure accuracy.