Fel-Pro 35666 Engine Coolant Thermostat Seal

Fel-Pro 35666 Engine Coolant Thermostat Seal

Fel-Pro 35666 is an engine coolant thermostat seal with a 1.560" inside diameter, built for direct-fit sealing in a wide range of GM vehicles. It is a practical choice when servicing the thermostat housing on applications such as Buick Regal, Chevrolet Impala, and Pontiac Grand Prix models.

Key Features

• 1.560" inside diameter for the specified thermostat sealing application
• Application-specific sealing material for vehicle-focused fitment
• Engine coolant thermostat seal for cooling system service
• Fits a broad range of Buick, Chevrolet, GMC, Oldsmobile, and Pontiac models
• Fel-Pro part number 35666 for easy identification

Product Details

Fel-Pro 35666 is an engine coolant thermostat seal engineered around the listed 1.560-inch ID dimension to support a proper seal at the thermostat housing. Fel-Pro gaskets are known for vehicle-specific sealing solutions, and this part follows that approach with materials selected for the cooling system environment. This part cross-references MAHLE C31227 and C31979 for the same application. It is commonly searched as a thermostat seal for Buick Regal, Chevrolet Impala, and Pontiac Grand Prix cooling system repair.

Vehicle Fitment

• Fits 2005-2009 Buick Allure, N/A
• Fits 2005-2009 Buick LaCrosse, N/A
• Fits 2006-2008 Buick Lucerne, N/A
• Fits 1997-2008 Pontiac Grand Prix, N/A
• Fits 1992-2005 Buick LeSabre, N/A
• Fits 1991-2005 Buick Park Avenue, N/A
• Fits 2000-2005 Chevrolet Impala, N/A
• Fits 1998-2005 Chevrolet Monte Carlo, N/A
• Fits 1992-2005 Pontiac Bonneville, N/A
• Fits 1990-2004 Buick Regal, N/A
• Fits 1995-2002 Chevrolet Camaro, N/A
• Fits 1995-2002 Pontiac Firebird, N/A
• Fits 1995-1999 Buick Riviera, N/A
• Fits 1991-1993 Buick Riviera, N/A
• Fits 1998-1999 Chevrolet Lumina, N/A
• Fits 1992-1999 Oldsmobile 88, N/A
• Fits 1998-1999 Oldsmobile Intrigue, N/A
• Fits 1996-1999 Oldsmobile LSS, N/A
• Fits 1997-1998 Oldsmobile Regency, N/A
• Fits 1991-1996 Oldsmobile 98, N/A
• Fits 1992-1995 Chevrolet Astro, N/A
• Fits 1995 Chevrolet Blazer, N/A
• Fits 1992-1995 Chevrolet Lumina APV, N/A
• Fits 1992-1995 Chevrolet S10, N/A
• Fits 1992-1995 GMC Jimmy, N/A
• Fits 1992-1995 GMC Safari, N/A
• Fits 1992-1995 GMC Sonoma, N/A
• Fits 1992-1995 Oldsmobile Silhouette, N/A
• Fits 1992-1995 Pontiac Trans Sport, N/A
• Fits 1992-1994 Chevrolet S10 Blazer, N/A
• Fits 1992-1994 Oldsmobile Bravada, N/A
• Fits 1989-1993 Buick Century, N/A
• Fits 1989-1993 Buick Skylark, N/A
• Fits 1992-1993 Oldsmobile Achieva, N/A
• Fits 1989-1993 Oldsmobile Cutlass Ciera, N/A
• Fits 1989-1993 Oldsmobile Cutlass Cruiser, N/A
• Fits 1992-1993 Pontiac Grand Am, N/A
• Fits 1991-1992 Oldsmobile Toronado, N/A
• Fits 1991 Buick Reatta, N/A
• Fits 1989-1991 Oldsmobile Cutlass Calais, N/A

Common Repair Uses

• Replacing a leaking thermostat seal during cooling system service
• Restoring a tight seal at the thermostat housing
• Addressing coolant seepage around the thermostat area
• Supporting maintenance on GM engines that use a 1.560" ID seal
• Helping correct overheating concerns caused by seal failure

Installation Notes

Verify the thermostat housing style and confirm the 1.560-inch inside diameter before installation. Clean the sealing surfaces thoroughly, inspect the housing for corrosion or damage, and follow the vehicle service procedure for coolant refill and bleed-off after assembly. For best results, match the seal to the exact application listed for your Buick, Chevrolet, GMC, Oldsmobile, or Pontiac model.

Quality Assurance

Fel-Pro focuses on application-specific sealing materials and vehicle-focused gasket design for dependable cooling system service. Part number 35666 is built to meet the listed thermostat seal application requirements.