If you still have the stock catalytic converters (“cats”) on your exhaust system you may see the “overheat exhaust system” warning light on the instrument panel light up. This requires attention because it means that your pre-cats (the ones ahead of the main cat) are plugging up from years of exhaust deposits. This plugging up causes the exhaust to overheat, and some of that heat will cause local overheating of the engine that won’t show up on the temp guage.

The cure is to remove the pre-cats The main cat typically doesn’t plug, in spite of what some mechanics may tell you in an effort to sell you a new (expensive) main cat. Next, use a welding rod or other slim object to punch the deposits out of the pre-cats and then re-install them.

Written by
Rotor Head