The Enginetech S5125 is a 1-piece silicone rear main seal engineered as a stock replacement for 1979-1993 American Motors, Buick, Chevrolet, GMC and more engine applications.
Important Notes
- 1-Piece design: verify your engine uses a 1-piece seal before ordering - 1-piece and 2-piece seals are not interchangeable.
- Silicone construction: broad temperature tolerance and strong chemical resistance for modern oil formulations.
Specifications
| Brand | Enginetech |
| Part Number | S5125 |
| Product Type | Rear Main Seal |
| Design | 1-Piece |
| Material | Silicone |
| OEM / Aftermarket Cross References | FEL-PRO:BS40578, Victor Reinz:JV553, Detroit Diesel:17170 |
Vehicle Fitment
- Years: 1979-1993
- Makes: American Motors, Buick, Chevrolet, GMC, Jeep, Pontiac
- Models: 6000, Astro, CJ5, CJ7, Celebrity, Century, Citation II, Concord, DJ5, Eagle, Firebird, Grand Am, LLV, Lumina, Monza, Phoenix, S10, S10 Blazer, S15, S15 Jimmy, Safari, Scrambler, Skylark, Somerset, Somerset Regal, and more
The rear main seal (also called the crankshaft rear seal) prevents engine oil from leaking between the back of the crankshaft and the transmission bell housing. Over miles and heat cycles, the seal hardens, cracks, or takes a permanent compression set - producing the characteristic oil drip at the bell housing and, if left unchecked, oil contamination of the clutch disc or flex plate. Replacing the rear main seal during a transmission service or engine rebuild restores the final oil seal between the crankshaft and drivetrain, preventing slow leaks and protecting the clutch and flywheel from contamination.
