1989-1993 Dodge 5.9L Cummins Exhaust Manifolds

Exhaust manifolds on the 1989-1993 RAM 5.9L Cummins

The first-gen 5.9L Cummins uses a cast one-piece exhaust manifold bolted to a cast-iron cylinder head. It collects exhaust from all six cylinders and feeds the Holset H1C turbo through a T3 divided flange. Every drive heats the manifold and its fasteners, and every shutdown lets them cool. After decades of that cycle, the joint between manifold and head takes the punishment, which is why this collection centers on gaskets and bolts.

What fails and why

Two problems show up on these manifolds. The first is fastener and gasket failure: bolts loosen and gaskets leak under heat cycling as the engine ages. Signs are a ticking at the head, soot streaks at the manifold and exhaust gas temperatures that creep up. The second is the casting itself cracking or warping, which is more common on hard-worked trucks and trucks running more boost than stock. Watch for exhaust leak noise, a loss of boost and visible cracks between the runners.

Stock replacement vs. upgrade

For a leak on a sound manifold, new gaskets and better fasteners are the fix. The aftermarket answer for 12-valves is multi-layer steel (MLS) gaskets with locking bolts or stainless stud kits, and manifold blankets are used to bring down underhood temperatures. For a cracked casting, replacement manifolds that list 1989-1998 12-valve fitment include BD's 3-piece T3 and high-silicon ductile-iron pulse manifolds, the ATS PulseFlow, and Steed Speed's angled T3 and T6 competition manifolds. Documented first-gen builds run 3-piece and Steed Speed manifolds with S300 turbos. Those castings aren't part of this collection, so call the shop and we'll help you sort out which way to go.

What we carry

Exhaust manifold gasket sets from Mahle (MS10141) and BD Diesel (1045981), both listed for 1989-1998 5.9L Cummins. The XDP XD230 stainless steel exhaust manifold bolt kit, listed for 1989-2018 5.9L and 6.7L Cummins. And the ATS 213-045-1000 45 mm wastegate adapter, a part for modified turbo setups built around a 45 mm wastegate rather than a stock repair item. More is in our full exhaust section.

Fitment notes

The gasket sets here are listed for the whole 1989-1998 12-valve run, so they cover the first-gen VE-pump years as well as the 1994-1998 trucks. The XDP bolt kit spans both 5.9L and 6.7L Cummins. If your truck has a non-stock turbo or manifold, the flange may no longer be the factory T3 pattern, so match gaskets and adapters to the hardware actually on your engine. Use the fitment checker on each product page, and verify by VIN.

Frequently asked questions

How do I tell a loose manifold from a cracked one?

Loose bolts or a failed gasket typically show up as ticking at the head and soot streaks at the manifold, sometimes with EGT creep. A cracked casting brings exhaust leak noise, a loss of boost and visible cracks between the runners. Inspect the manifold closely before you order parts.

Should I reuse the factory manifold bolts?

Bolt loosening under heat cycling is part of the leak problem on these engines, so it's worth replacing them when you change the gaskets. The XDP stainless bolt kit in this collection replaces the factory bolts, and locking bolts and stud kits are the other common upgrades for 12-valves.

Do I need the ATS wastegate adapter on a stock truck?

It's built for modified turbo setups that use a 45 mm wastegate. If you're fixing a leak on a stock manifold, the gasket sets and bolt kit here are what the job calls for.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.