Product Description
Interstate-McBee M-4089651 Upper Engine Gasket Set — .020" Oversize — 89–98 5.9L Cummins 12-Valve
Premium aftermarket upper (top end) gasket set for the 1989–1998 Dodge Ram 5.9L Cummins 12-valve (6BT). Includes a .020" oversize head gasket for resurfaced/milled heads or blocks. OE-style materials and fit. Designed as a complete top-end refresh kit.
Highlights
- .020" oversize head gasket: Correct compressed thickness for engines requiring oversize after machining.
- Complete top-end kit: Covers intake/exhaust, valve cover, rocker box, and common coolant/oil seals.
- Interstate-McBee quality: Trusted materials for sealing consistency and service life.
Specifications
| Brand | Interstate-McBee |
| Part Number | M-4089651 |
| Application | 5.9L Cummins 12-valve (6BT), 1989–1998 |
| Gasket Type | Upper (Top End) Set |
| Head Gasket Thickness | .020" oversize |
| Sold As | Kit |
What’s Included*
- .020" OS multi-layer/composite head gasket
- Intake manifold gasket(s)
- Exhaust manifold gasket(s)
- Rocker box / upper valve cover gasket(s)
- Main valve cover gaskets
- Valve stem seals
- Injector sealing washers/o-rings (as applicable)
- Thermostat housing gasket
- Misc. coolant and oil seals for the top end
*Contents may vary slightly by production revision. Refer to the photo/listing contents for your exact kit.
Vehicle Fitment
Always verify by engine serial number (ESN) when possible.
- Dodge Ram 2500/3500 with 5.9L Cummins 12-valve (6BT)
- Model Years: 1989–1998
- Other B-Series 5.9L 12V applications where a .020" OS head gasket is specified.
Install Notes
- Confirm required head gasket thickness after measuring piston protrusion and deck/head machining.
- Clean and dry mating surfaces; follow Cummins torque/angle specs and sequence.
- Replace head bolts if required (or use appropriate studs); lubricate threads/washers per manufacturer instructions.
- Recheck final torque after initial heat cycle if your fastener manufacturer specifies it.
Why Buy From CPP Diesel
- Knowledgeable diesel support (ESN verification available)
- Fast shipping and competitive pricing
- Huge selection of complementary 6BT components
FAQ
What does .020" oversize mean?
It refers to a thicker-than-stock head gasket used to compensate for material removed during head/block machining. Verify required thickness by measuring piston protrusion and deck height.
Is this for 12-valve only?
Yes. This kit is for 1989–1998 5.9L Cummins 12-valve engines. It does not fit 24-valve (1998.5–2002) engines.
Do I need new head bolts?
Head bolts are not included. Inspect and follow Cummins guidance; many installers choose new bolts or performance studs.
