Symptoms
A ticking or puffing noise at cold start that quietens as the engine warms, a smell of exhaust in the engine bay, and soot marks at the manifold-to-head joint.
The fix, step by step
- Driving Line names cracked exhaust manifolds as a 3.8 weak point.
- Soak the studs in penetrating oil the night before.
- Unbolt the heat shield and the downpipe flange, then remove the manifold nuts.
- Inspect the studs and replace any that are stretched or corroded.
- Clean the head flange, fit new gaskets and a new manifold, and torque the nuts evenly from the center out.
- Check the oxygen sensor connectors and the downpipe gasket while you're in there.
Tools & part numbers
- Penetrating oil
- long extensions and swivels
- stud extractor
- torque wrench
- new manifold studs and nuts.
Where to buy the parts
OMIX 17626.02 exhaust manifold, 2007–2011 JK 3.8Quadratec ↗Amazon ↗
AccuPart exhaust manifold, 2007–2011 JK 3.8Quadratec ↗Amazon ↗
Mopar 04892409AA exhaust manifold gasket, 2007–2011 JK 3.8Quadratec ↗Amazon ↗
JK stock replacement exhaustExtremeTerrain ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Jeep Wrangler JK Unlimited parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.