Ask Don · 20261005_160000_stant-27273-thermostat-seal-fitment-guide

Stant 27273 Thermostat Seal – Fitment Guide for Buick, Chevrolet, GMC, Oldsmobile, Pontiac, Subaru (1980–1994)

Buick, Chevrolet, GMC, Oldsmobile, Pontiac, Subaru (1980–1994)

Stant 27273 Engine Coolant Thermostat Seal – from Don's Obsolete Auto Parts

Keep your car or truck on the road with a genuine Stant 27273, the Stant thermostat seal for GM 3.3L and 3.8L V6 cars (Buick, Oldsmobile, Pontiac, 1986–1994, plus the 1980–1981 Monte Carlo 3.8L), the 1992–1994 4.3L V6 (Eng. VIN W) in the Astro, S-10, Blazer, Jimmy, Safari, Sonoma and Bravada, and the 1987–1989 Subaru Justy. A thermostat seal is a molded rubber ring that seals the thermostat or the water outlet instead of a flat paper gasket. Stant's description of these seals: no sealer or RTV is needed, and each one is shaped for its application.

Key Features

• Part Number: Stant 27273 (single pack); same seal as Stant 25273 in the Stant catalog
• Type: Engine coolant thermostat / water outlet seal (rubber, grooved, molded style per the Gates equivalent)
• Size: about 1.56 in. inside diameter × 1.636 in. outside diameter × 0.27 in. thick (Gates 33609 data for the direct equivalent)
• Cross-references: Gates 33609; Carquest 30769; General Motors 10144187, 24502433, 24506985, 24535126, 25535126; Ideal Tridon 30769; Motorad MG183; NAPA 1077; Pep Boys 35486; Standard Thomson 1077

Stant's own 1928–1994 application catalog lists the 27273 for 6 makes from 1980 to 1994. It's a good fit for restoration projects, weekend drivers and mechanics keeping older vehicles running.

Compatible Makes & Models (from the Stant catalog)

• Buick (1986–1994): Century (1986–1993), Electra (1986–1987), LeSabre (1986–1988, 1992–1994), Park Avenue (1991–1994), Reatta (1991), Regal (1986–1987, 1990–1994), Riviera (1986–1987, 1991–1993), Skylark (1989–1993)
• Chevrolet (1980–1994): Astro (1992–1994), Blazer Compact (S-10 Blazer) (1992–1994), Lumina APV (1992–1994), Monte Carlo (1980–1981), S Series Pickup (S-10) (1993–1994)
• GMC (1992–1994): Jimmy (1992–1994), Safari (1992–1994), Sonoma (1992–1994)
• Oldsmobile (1986–1994): Achieva (1992–1993), Bravada (1992–1994), Cutlass (1986), Cutlass Calais (1989–1991), Cutlass Ciera (1986–1993), Cutlass Cruiser (1990–1993), Delta 88 (1986–1988), Eighty Eight (1992–1994), Ninety Eight (1986–1987, 1991–1994), Silhouette (1992–1994), Toronado (1986–1987, 1991–1992)
• Pontiac (1987–1994): Bonneville (1987, 1992–1994), Firebird (1989), Grand Am (1992–1993), Trans Sport (1992–1994)
• Subaru (1987–1989): Justy (1987–1989)

Note: Always verify fitment for your specific year, make, model and engine. Some catalog lines are limited to one engine code or housing type; the full engine-by-engine list is in the fitment appendix below. If you have your old seal, compare its size and shape, or just ask Don and Kathy.

Price is $9.95 plus $3.00 for shipping. Don and Kathy offer a fair deal for this. Buying for a club, a shop, or a whole fleet of project cars? Even better.

Why Buy From Don & Kathy at Don's Obsolete Auto Parts? Don Leask founded one of the earliest online obsolete auto parts businesses (carparts2 on eBay in 1997, the second auto parts store on eBay) and grew it to 11,000–17,000 unique listings. Today, with help from their digital agent Misty ([email protected]), Don and Kathy connect directly with restorers and collectors while preserving their legacy of quality parts. These seals come from Don's own shelves.

To reach them, click the "Don & Kathy Leask" button at the bottom left of any page on donsobsoleteautoparts.com, or email [email protected].

The Stant 27273 Thermostat Seal: The Right Seal for Buick and Chevrolet Owners

Thermostat seals are small, but they decide whether a cooling system stays dry. When the thermostat housing comes off, the right seal is the quiet part that keeps the job from turning into a second trip to the parts counter.

Why This Seal Matters Stant's application catalog covering 1928 through 1994 lists the 27273 across 6 makes (Buick, Chevrolet, GMC, Oldsmobile, Pontiac, Subaru). Cross-reference tables tie it to the Stant 25273 and Gates 33609, which makes it easy to match against an old parts list or a worn-out seal.

Real-World Fitment Examples

• 1989–1993 Buick Century V-6 3.3L
• 1993–1994 Chevrolet Astro V-6 4.3L
• 1993–1994 GMC Jimmy V-6 4.3L
• 1993 Oldsmobile Achieva V-6 3.3L
• 1992–1994 Pontiac Bonneville V-6 3.8L
• 1987–1989 Subaru Justy 3-Cyl. 1.2L

Keeping Older Cars on the Road Don and Kathy Leask have been part of the classic car world since the early days of the internet. Starting with carparts2 on eBay in 1997, they became one of the largest online sellers of obsolete parts. Now, with their Don's Obsolete Auto Parts site and digital agent Misty, they're making hard-to-find parts discoverable again, connecting owners of rare inventory with the enthusiasts who need them.

Buying Tips

• Match three things before ordering: year, model and engine. Watch for catalog notes such as engine VIN codes or housing type.
• Compare sizes: the 27273 is about 1.56 in. inside diameter × 1.636 in. outside diameter × 0.27 in. thick.
• Some engines use a gasket and a seal at the thermostat; check what came off yours.
• Restoration shops, clubs and collectors can ask about quantity pricing.

Fitment appendix — every Stant catalog line for

27273

Source: Stant Thermostats, Gaskets, Caps – 1928 through 1994 (application pages). Format: Model — years [engine: years (catalog notes)]. Catalog coverage ends with 1994 models.

Buick

• Century — 1986–1993 [V-6 3.3L: 1989–1993 | V-6 3.8L: 1986–1988]
• Electra — 1986–1987 [V-6 3.8L: 1986–1987]
• LeSabre — 1986–1988, 1992–1994 [V-6 3.8L: 1986–1988, 1992–1994 (1988: engine VIN code 3)]
• Park Avenue — 1991–1994 [V-6 3.8L: 1991–1994]
• Reatta — 1991 [V-6 3.8L: 1991]
• Regal — 1986–1987, 1990–1994 [V-6 3.8L: 1986–1987, 1990–1994 (1986–1987: with turbo)]
• Riviera — 1986–1987, 1991–1993 [V-6 3.8L: 1986–1987, 1991–1993]
• Skylark — 1989–1993 [V-6 3.3L: 1989–1993]

Chevrolet

• Astro — 1992–1994 [V-6 4.3L: 1992–1994 (1992–1994: engine VIN code W)]
• Blazer Compact (S-10 Blazer) — 1992–1994 [V-6 4.3L: 1992–1994 (1992–1994: engine VIN code W)]
• Lumina APV — 1992–1994 [V-6 3.8L: 1992–1994]
• Monte Carlo — 1980–1981 [V-6 3.8L: 1980–1981 (1980–1981: engine VIN code 3)]
• S Series Pickup (S-10) — 1993–1994 [V-6 4.3L: 1993–1994 (1993–1994: engine VIN code W)]

GMC

• Jimmy — 1992–1994 [V-6 4.3L: 1992–1994 (1992–1994: engine VIN code W)]
• Safari — 1992–1994 [V-6 4.3L: 1992–1994 (1992–1994: engine VIN code W)]
• Sonoma — 1992–1994 [V-6 4.3L: 1992–1994 (1992–1994: engine VIN code W)]

Oldsmobile

• Achieva — 1992–1993 [V-6 3.3L: 1992–1993]
• Bravada — 1992–1994 [V-6 4.3L: 1992–1994 (1992: engine VIN code W)]
• Cutlass — 1986 [V-6 3.8L: 1986]
• Cutlass Calais — 1989–1991 [V-6 3.3L: 1989–1991]
• Cutlass Ciera — 1986–1993 [V-6 3.3L: 1989–1993 | V-6 3.8L: 1986–1988 (1986–1988: without 1-bolt housing)]
• Cutlass Cruiser — 1990–1993 [V-6 3.3L: 1990–1993]
• Delta 88 — 1986–1988 [V-6 3.8L: 1986–1988 (1988: engine VIN code 3; 1986–1987: without 1-bolt housing)]
• Eighty Eight — 1992–1994 [V-6 3.8L: 1992–1994]
• Ninety Eight — 1986–1987, 1991–1994 [V-6 3.8L: 1986–1987, 1991–1994 (1986–1987: without 1-bolt housing)]
• Silhouette — 1992–1994 [V-6 3.8L: 1992–1994]
• Toronado — 1986–1987, 1991–1992 [V-6 3.8L: 1986–1987, 1991–1992 (1986–1987: without 1-bolt housing)]

Pontiac

• Bonneville — 1987, 1992–1994 [V-6 3.8L: 1987, 1992–1994]
• Firebird — 1989 [V-6 3.8L: 1989]
• Grand Am — 1992–1993 [V-6 3.3L: 1992–1993]
• Trans Sport — 1992–1994 [V-6 3.8L: 1992–1994]

Subaru

• Justy — 1987–1989 [3-Cyl. 1.2L: 1987–1989]

Cross-references (full)

• Gates: 33609
• Carquest: 30769
• General Motors: 10144187, 24502433, 24506985, 24535126, 25535126
• Ideal Tridon: 30769
• Motorad: MG183
• NAPA: 1077
• Pep Boys: 35486
• Standard Thomson: 1077
• Stant equivalents: 25273, 30769, C73

Sources

1. Stant Thermostats, Gaskets, Caps – 1928 through 1994 catalog (scan on Internet Archive): https://archive.org/details/StantThermostatsGasketsCaps1928Through1994OCR637Pages — part-number index ("Make / Year(s)" table at the back of the catalog) and application pages (PDF pages 320, 322, 324, 326, 327, 329, 333, 345, 352, 353, 376, 379, 386, 468, 473, 474, 475, 536, 538, 540, 541, 542, 543, 544, 545, 547, 551, 573, 579, 582, 600, 611). Every catalog line pairs "Thermostat Seal 25273" with "Thermostat Seal (1 Pack) 27273".
2. PartsHawk – Gates 33609 (interchange lists Stant 27273; style and dimensions): https://partshawk.com/gates-33609-engine-coolant-thermostat-seal.html
3. AutoPartsPrime – Stant 27273 ("Engine Coolant Thermostat Seal"; UPC 033342072732; vehicle list): https://www.autopartsprime.com/stant/engine-coolant-thermostat-seal/mp-27273
4. PartsHawk – Stant 27273 (fitment list): https://partshawk.com/stant-27273-engine-coolant-thermostat-seal.html

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