TECHLINE
YJ EXHAUST LEAK
QI have a ’87 Jeep YJ Wrangler with a 4.2L inline-six engine. I replaced the cracked exhaust manifold with an aftermarket manifold. Now, two months later the intake and exhaust bolts have worked loose due to the metal expanding and contracting. I have heard this is a common problem. Is there anything to be done other than having to tighten the bolts again and again?
RICHARD DRECHSEL
AUnfortunately, exhaust manifold gaskets and bolts often need to seat, especially on the longer inline-six engines like your 4.2L. You may need to retighten the hardware several times before the exhaust is completely seated. Use a torque wrench and tighten each bolt to spec in the appropriate pattern, which is generally from the inner bolts outward. In some cases, the cast-iron exhaust manifold will warp and never seal properly. The Jeep inline-six) offer a header for the Jeep YJ 4.2L. If you decide on going with a header, steer into a ceramic-coated version if you live in a wet state or regularly hit mudholes. The ceramic coating will help keep the header from corroding.
