---
id: 20261005_160000_stant-27277-pontiac-bonneville-1988-1991
title: Stant 27277 Thermostat Seal for Pontiac Bonneville (1988–1991)
category: Parts Catalog
corpus_topic: PartsCatalog
site_category: Parts Catalog
summary: Stant 27277 thermostat seal (Gates 33610), fitting the Pontiac Bonneville (1988–1991) per Stant's 1928–1994 catalog. Offered by Don and Kathy Leask of Don's Obsolete Auto Parts, restoration parts sellers online since 1997. Price is $9.95 plus $3.00 for shipping.
description: Stant 27277 thermostat seal (Gates 33610), fitting the Pontiac Bonneville (1988–1991) per Stant's 1928–1994 catalog. Offered by Don and Kathy Leask of Don's Obsolete Auto Parts, restoration parts sellers online since 1997. Price is $9.95 plus $3.00 for shipping.
question: Will the Stant 27277 thermostat seal fit my Pontiac Bonneville, and who can I buy it from?
keypoints:
- Pontiac Bonneville (1988–1991)
- 'Engines listed: V-6 3.8L'
- Same seal as Gates 33610
- Price is $9.95 plus $3.00 for shipping.
tags:
- stant
- stant-27277
- thermostat-seal
- water-outlet-seal
- restoration-parts
- obsolete-auto-parts
- pontiac
- pontiac-bonneville
consent: true
agent: misty
created: '2026-10-06T21:37:26Z'
updated: '2026-10-06T22:08:48Z'
date: '2026-10-05'
vault_stage: 07_CODEX
enrich_status: ok
enrich_method: bot
enrich_blockers: []
pipeline_filename: stant-27277-pontiac-bonneville-1988-1991.md
source_kind: authored
proposed_topic: PartsCatalog
lane: PartsCatalog
content_status: approved
routing_source: carbon
prefix: misty
headwaters: misty
voice: misty
active_voice: misty
voices:
- misty
asker_site: donsobsoleteautoparts.com
sample: false
sentiment: helpful
emotions:
- reassured
- nostalgic
- confident
sycophancy: 0
truth_score: 9
entropy: 3
predicted_narrative_arc: owner-searching-to-part-found
share_url: https://donsobsoleteautoparts.com/kb/PartsCatalog/stant-27277-pontiac-bonneville-1988-1991.md
source_url: ''
part_number: Stant 27277
requested_by: Kathy Leask (email 2026-10-05 3:14 PM PT, msg_0859fa0d63994b9eb5832c2c51135a79)
approved_by: 'Daniel Comp APPROVED Oct 6, 2026 ~2:24 PM PT: apply Don Leask pricing block to ALL Stant pages on DOAP and finish posting remaining seal pages'
vehicle: Pontiac Bonneville
---

# Stant 27277 Thermostat Seal for Pontiac Bonneville, 1988–1991

Don's very first car was a 1936 Pontiac convertible, bought by his father for about $600 when Don was in high school in Saskatchewan. So Pontiac has a special place in this shop.

This page is for one model only: the Pontiac Bonneville. It isn't a wall of every car ever made, just yours.

## Model this seal fits

- Pontiac Bonneville (1988–1991)
- V-6 3.8L: 1988–1991 — catalog note: 1988: engine VIN code C

## Help choosing the right seal

The 27277 is a Stant thermostat seal, a molded rubber ring that seals the thermostat or the water outlet (thermostat housing) instead of a flat paper gasket. Its Gates equivalent, Gates 33610, is described as a molded seal, about 1.07 in. inside diameter × 1.46 in. outside diameter × 0.105 in. thick. Stant's own description of these seals: no sealer or RTV is needed for a leak-proof seal, and each one is shaped for its application. Stant made a different seal for each housing design, and Don stocks several of them, so check which number your car calls for.

Before you order, match three things: your year, your model, and your engine. Catalogs list fitment by vehicle, but some engines had more than one thermostat housing design over the years. If your old seal is still in hand, compare its size and shape, or just ask Don and Kathy. They'll help you sort it out.

## Real people behind the parts

Don was born in 1936 and grew up on a Saskatchewan farm, four miles from a town of about 150 people. As a young man he drove trucks through deep snow in Canada's Northwest Territories, hauling dynamite to seismic crews. Kathy grew up in South Dakota, blizzards and all. Together they've spent close to three decades helping people keep old cars on the road.

These seals come from Don's own shelves.

## 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.

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