Instant Rebates
800.345.4545
Call Our Support Line
24 Hours / 7 Days a Week!  
FREE SHIPPING!
Same Day Shipping Before 11 PM ET
0
My Cart
0
$0.00
Shop By Vehicle
Shop By
Category
Close Menu
Shop By Vehicle
Top Categories
All Categories

All Categories


Free Catalog
E-Mail Signup
My Account
Track Order
Gift Certificates
Rebates
Help

ACDelco 12S21

SEAL ENG COOL THERM

ACDelco 12S21

065-12S21

jegs shipping
Estimated ship date 10/30/17 if Ordered Today
Easy Returns
Easy Returns
Lowest Price Guarantee
Lowest Price Guarantee
ACDelco 12S21 SEAL ENG COOL THERM $1.69
  • Engine Coolant Thermostat Seal

  • Specifications:

    Material
    Rubber
    Seal Type
    Gasket O Ring
    Inside Diameter
    1.969
    Inside Diameter (mm)
    50.00
    Outside Diameter
    2.323
    Outside Diameter (mm)
    59.00
    Thickness
    0.146
    Thickness (mm)
    3.700
    Manufacturer's Part Number:
    12S21

    Does ACDelco 12S21 fit your vehicle?

    Narrow Results

    1986-1990 CHEVROLET CELEBRITY

    • CC: 2474
    • Liter: 2.5
    • SubModel: EUROSPORT
    • CUI: 151
    • EngineType: L4 ( 2.5 L / 151 )

    1994 CHEVROLET C2500 PICKUP

    • CC: 5735
    • Liter: 5.7
    • SubModel: BASE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1993 GMC C1500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLX
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1995 CHEVROLET C1500 PICKUP

    • CC: 5031
    • Liter: 5.0
    • SubModel: WT
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1994-1995 GMC K2500 SUBURBAN

    • Liter: 5.7
    • SubModel: SLE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1994 CHEVROLET K1500 PICKUP

    • Liter: 5.7
    • Aspiration: N
    • SubModel: BASE
    • Engine Vin: K
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1995 GMC G15/G1500 VAN

    • Liter: 5.0
    • SubModel: VANDURA
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1969 CHEVROLET G20 VAN

    • CC: 5031
    • Liter: 5.0
    • SubModel: SPORTVAN
    • CUI: 307
    • EngineType: V8 ( 5.0 L / 307 )

    1982 CHEVROLET CELEBRITY

    • Liter: 2.8
    • SubModel: CS
    • CUI: 173
    • EngineType: V6 ( 2.8 L / 173 )

    1993-1995 CHEVROLET C1500 PICKUP

    • Liter: 4.3
    • SubModel: CHEYENNE
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1982-1983 PONTIAC 6000

    • CC: 2474
    • Liter: 2.5
    • SubModel: LE
    • CUI: 151
    • EngineType: L4 ( 2.5 L / 151 )

    1984 BUICK CENTURY

    • CC: 2474
    • Liter: 2.5
    • SubModel: OLYMPIA LIMITED
    • CUI: 151
    • EngineType: L4 ( 2.5 L / 151 )

    1992-1993 GMC K2500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1994 GMC C1500 PICKUP

    • Liter: 5.0
    • SubModel: SIERRA SLE
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1990-1991 BUICK SKYLARK

    • CC: 2474
    • Liter: 2.5
    • SubModel: BASE
    • CUI: 151
    • EngineType: L4 ( 2.5 L / 151 )

    1994 GMC SAFARI

    • EngineType: ALL
    • SubModel: SLX

    1995 GMC K1500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993-1994 GMC K1500

    • Liter: 5.0
    • SubModel: SIERRA SLE
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1995 CHEVROLET C2500 SUBURBAN

    • Liter: 5.7
    • SubModel: LS
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993-1996 CHEVROLET G30 VAN

    • Liter: 4.3
    • SubModel: CHEVY VAN
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1995 GMC K1500 SUBURBAN

    • Liter: 5.7
    • SubModel: SLE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1983 OLDSMOBILE CUTLASS CIERA

    • CC: 2474
    • Liter: 2.5
    • SubModel: ES
    • CUI: 151
    • EngineType: L4 ( 2.5 L / 151 )

    1992-1995 CHEVROLET K3500 PICKUP

    • Liter: 5.7
    • SubModel: CHEYENNE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 CHEVROLET C2500 SUBURBAN

    • Liter: 5.7
    • SubModel: LT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 CHEVROLET K1500 SUBURBAN

    • Liter: 5.7
    • SubModel: LT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1993 GMC K3500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1985 OLDSMOBILE CUTLASS CIERA

    • CC: 2474
    • Liter: 2.5
    • SubModel: ES
    • CUI: 151
    • EngineType: L4 ( 2.5 L / 151 )

    1994-1995 CHEVROLET K3500 PICKUP

    • Liter: 5.7
    • SubModel: BASE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1994 GMC YUKON

    • Liter: 5.7
    • SubModel: SPORT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993-1995 CHEVROLET G20 VAN

    • Liter: 4.3
    • SubModel: BEAUVILLE
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1993-1995 GMC G35/G3500 VAN

    • Liter: 4.3
    • SubModel: VANDURA SPECIAL
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992-1993 CHEVROLET G10 VAN

    • Liter: 5.7
    • Aspiration: N
    • SubModel: SPORTVAN
    • Engine Vin: K
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 CHEVROLET K2500 SUBURBAN

    • Liter: 5.7
    • SubModel: LT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1985-1988 PONTIAC 6000

    • CC: 2474
    • Liter: 2.5
    • SubModel: BASE
    • CUI: 151
    • EngineType: L4 ( 2.5 L / 151 )

    1994-1995 GMC C2500 PICKUP

    • Liter: 4.3
    • SubModel: SIERRA SL
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992-1995 CHEVROLET K1500 PICKUP

    • Liter: 5.7
    • SubModel: CHEYENNE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 GMC K1500 PICKUP

    • Liter: 4.3
    • SubModel: SIERRA SLE
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992-1995 CHEVROLET C1500 PICKUP

    • Liter: 5.7
    • SubModel: CHEYENNE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 GMC K1500 PICKUP

    • Liter: 5.0
    • SubModel: SIERRA SLS
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1992-1993 GMC C2500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLX
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1995 GMC G35/G3500 VAN

    • Liter: 5.7
    • SubModel: RALLY
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993-1994 CHEVROLET S10 PICKUP

    • Liter: 4.3
    • SubModel: BASE
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992-1995 GMC K2500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993-1994 CHEVROLET ASTRO

    • EngineType: ALL
    • SubModel: ALL

    1992 CHEVROLET C3500 PICKUP

    • Liter: 5.7
    • SubModel: SCOTTSDALE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992 CHEVROLET C2500 PICKUP

    • Liter: 5.7
    • SubModel: SCOTTSDALE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 GMC K1500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1994 CHEVROLET K2500 SUBURBAN

    • Liter: 5.7
    • SubModel: SILVERADO
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 GMC K1500 SUBURBAN

    • Liter: 5.7
    • SubModel: SLT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 GMC YUKON

    • Liter: 5.7
    • SubModel: SLT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 GMC K1500 PICKUP

    • Liter: 5.0
    • SubModel: SIERRA SLT
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1993 GMC K1500

    • Liter: 4.3
    • SubModel: SIERRA SLX
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1969 CHEVROLET G10 VAN

    • Liter: 5.0
    • SubModel: BASE
    • CUI: 307
    • EngineType: V8 ( 5.0 L / 307 )

    1992-1995 CHEVROLET K2500 PICKUP

    • CC: 5031
    • Liter: 5.0
    • SubModel: CHEYENNE
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1992 CHEVROLET C1500 PICKUP

    • CC: 5031
    • Liter: 5.0
    • SubModel: SCOTTSDALE
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1994-1995 GMC K3500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1994 CHEVROLET S10 PICKUP

    • Liter: 4.3
    • SubModel: LS
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992-1995 GMC G25/G2500 VAN

    • Liter: 5.0
    • SubModel: RALLY STX
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1992-1995 CHEVROLET K2500 SUBURBAN

    • Liter: 5.7
    • SubModel: BASE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1994-1995 CHEVROLET C3500 PICKUP

    • Liter: 5.7
    • SubModel: BASE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1994-1995 GMC K2500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995-1996 CHEVROLET G30 VAN

    • Liter: 5.7
    • SubModel: SPORTVAN
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992 GMC K1500 PICKUP

    • Liter: 5.0
    • SubModel: SIERRA SLE
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1995 GMC C1500 PICKUP

    • CC: 5031
    • Liter: 5.0
    • SubModel: SIERRA SLT
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1993-1995 GMC C1500 PICKUP

    • Liter: 4.3
    • SubModel: SIERRA SLE
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992-1994 GMC C1500 SUBURBAN

    • EngineType: ALL
    • SubModel: ALL

    1994-1995 GMC C1500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993-1995 GMC C1500 PICKUP

    • Liter: 4.3
    • SubModel: SIERRA XC
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1993 GMC K1500

    • Liter: 5.7
    • SubModel: SIERRA SPORT
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992 GMC K1500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1995 CHEVROLET K1500 PICKUP

    • CC: 5031
    • Liter: 5.0
    • SubModel: CHEYENNE
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1993-1995 CHEVROLET C1500 PICKUP

    • Liter: 4.3
    • SubModel: SILVERADO
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992-1995 CHEVROLET K1500 PICKUP

    • Liter: 5.7
    • SubModel: SILVERADO
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993-1994 GMC SAFARI

    • EngineType: ALL
    • SubModel: SLE

    1994-1995 GMC C1500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SPECIAL
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 CHEVROLET K1500 SUBURBAN

    • Liter: 5.7
    • SubModel: LS
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993 CHEVROLET K2500 SUBURBAN

    • Liter: 5.7
    • SubModel: SLE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1996 CHEVROLET G30 VAN

    • Liter: 5.7
    • SubModel: HI-CUBE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1994-1995 CHEVROLET K2500 PICKUP

    • CC: 5031
    • Liter: 5.0
    • SubModel: WT
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1995 GMC K1500 PICKUP

    • Liter: 4.3
    • SubModel: SIERRA SLT
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1994-1995 CHEVROLET C2500 PICKUP

    • Liter: 4.3
    • SubModel: BASE
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992-1995 CHEVROLET K2500 PICKUP

    • Liter: 5.7
    • SubModel: SILVERADO
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1996 CHEVROLET G30 VAN

    • Liter: 5.7
    • Aspiration: N
    • SubModel: SPORTVAN
    • Engine Vin: K
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1993 CHEVROLET C2500 PICKUP

    • CC: 5735
    • Liter: 5.7
    • SubModel: CHEYENNE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1982-1983 PONTIAC 6000

    • CC: 2474
    • Liter: 2.5
    • SubModel: BASE
    • CUI: 151
    • EngineType: L4 ( 2.5 L / 151 )

    1993-1994 CHEVROLET S10 BLAZER

    • EngineType: ALL
    • SubModel: ALL

    1993-1994 GMC K1500

    • Liter: 5.7
    • SubModel: SIERRA SLE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 GMC K1500 PICKUP

    • Liter: 4.3
    • SubModel: SIERRA SLS
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1992 GMC K1500 PICKUP

    • Liter: 5.0
    • SubModel: SIERRA
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1992-1995 GMC C2500 PICKUP

    • Liter: 5.7
    • SubModel: SIERRA SLE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1995 GMC C1500 PICKUP

    • CC: 5031
    • Liter: 5.0
    • SubModel: SIERRA SPECIAL
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1994 CHEVROLET S10 PICKUP

    • EngineType: ALL
    • SubModel: ZR2

    1992-1993 GMC C1500 PICKUP

    • Liter: 5.0
    • SubModel: SIERRA
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1992-1995 GMC G35/G3500 VAN

    • Liter: 5.7
    • SubModel: VANDURA SPECIAL
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1994-1995 CHEVROLET G10 VAN

    • EngineType: ALL
    • SubModel: SPORTVAN

    1992 GMC G15/G1500 VAN

    • Liter: 5.0
    • SubModel: RALLY STX
    • CUI: 305
    • EngineType: V8 ( 5.0 L / 305 )

    1967 CHEVROLET CAMARO

    • CC: 5736
    • Liter: 5.7
    • SubModel: RS
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1992-1995 CHEVROLET K3500 PICKUP

    • Liter: 5.7
    • SubModel: SILVERADO
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    1993-1995 CHEVROLET K1500 PICKUP

    • Liter: 4.3
    • SubModel: SILVERADO
    • CUI: 262
    • EngineType: V6 ( 4.3 L / 262 )

    1995 GMC C1500 SUBURBAN

    • Liter: 5.7
    • SubModel: SLE
    • CUI: 350
    • EngineType: V8 ( 5.7 L / 350 )

    Before you leave us... Receive a free catalog or join our email list

    Sign up to receive our catalog or subscribe to our email list now to see our exclusive email only specials, new products, and offers!

    Request CatalogJoin Email List