Review on 🚗 Dorman 674-247 High-Performance Exhaust Manifold for Mazda Models - Enhance Your Mazda's Performance! by Adam Hutchinson

Arrived damaged. Not damaged enough to justify a return, but one is enough for me to regrind the manifold mounting surface and buy 2 new gaskets for it. With metal shims it is imperative that they are straight and correct, any kinks can break the fit which can allow air to enter the system ahead of the O2 sensor causing it to code and the check engine light to illuminate. The seal between the collector and the downpipe was particularly bent, basically unusable. There were chips and cuts on the manifold seating surface, some due to manufacturing, some due to poor handling of the part. I sanded it down with a metal capable grinding wheel and was happy with the result. I don't know what's going on, but for the last year I've been getting bad parts from Dorman here. Your QC seems to have gone downhill. I'm not sure I'll buy anything from them again.