Q: My car has had to have the exhaust manifold replaced four times in 17 years due to cracks in the manifold itself.

Unfortunately, cracks on the passenger side OEM exhaust manifold is a common problem with heavy duty use of this engine: work trucks, motor homes, school buses, where the engine is run at high loads for extended periods. They tend to crack under the hot air riser sheet metal. Fortunately, the stock manifolds are relatively inexpensive and straightforward to replace. Headers are used by some, but they can have their own exhaust leak issues if they are poor quality.