If your vehicle’s repair procedure calls for RTV at the thermostat housing, Permatex Water Pump & Thermostat RTV Silicone Gasket Maker (item 22071) is the most directly specified option here: Permatex says it is formulated for thermostat housings and water pumps. That does not mean every thermostat gasket needs sealer. Follow the vehicle’s service information and the instructions for the specific gasket or sealant.
Which gasket sealer is best for a thermostat housing?
Choose the sealant the vehicle’s repair procedure specifies. When that procedure calls for RTV, Permatex Water Pump & Thermostat RTV Silicone Gasket Maker, item 22071, is a direct-fit candidate by application: Permatex describes it as a noncorrosive, sensor-safe RTV silicone gasket material formulated for water pumps and thermostat housings. Those are the manufacturer’s product claims, not the result of an independent comparison test. Permatex product information.
Other products also list thermostat housings as an application, but that alone does not establish that they are better or suitable for a particular vehicle. Do not choose by color or a broad “high-temperature” label; confirm that the vehicle procedure and the product directions match.
| Option | What the manufacturer states | When to consider it |
|---|---|---|
| Permatex Water Pump & Thermostat RTV, item 22071 | Formulated for water pumps and thermostat housings; described as sensor-safe and noncorrosive. Permatex | Only if the vehicle procedure calls for RTV or a formed-in-place seal. |
| Permatex Ultra Grey RTV | Thermostat housings and water pumps are among the listed applications, with product-specific directions. Permatex | Consider only if its requirements suit the application and the vehicle procedure allows it; the available product information does not show it is superior to item 22071. |
| Permatex High-Temp Red RTV | Thermostat housings are among the suggested applications. Permatex | Use only when the vehicle procedure and product instructions make it appropriate; do not select it by color alone. |
| Vehicle-specific gasket or water outlet | Fel-Pro describes different cooling-system gasket constructions and a PermaDryPlus design for certain warped or corroded flanges. Fel-Pro gasket information Fel-Pro water outlet gasket information | Match the part to the vehicle and engine, and follow its installation instructions. |
Does a thermostat housing gasket need sealer?
Not necessarily. Some replacement gaskets are designed to be installed clean and dry. Fel-Pro advises following the gasket or applicable instructions rather than adding RTV by default; excess or misplaced sealant can interfere with gasket compression or cause the gasket to slip. Fel-Pro guidance on gasket sealant.
#1 Best Overall
- Sensor-safe, noncorrosive RTV silicone gasket material formulated specifically for water pumps and thermostat housings.Fit Type: Universal Fit
- Highest water-glycol resistance available in an RTV silicone
- Superior adhesion and flexibility; can be used as a gasket maker or dressing
- Temperature Range: -65°F to 500°F (-54°C to 260°C) intermittent
- Suggested Applications: Water pump and thermostat housings
Check the vehicle service information and the instructions supplied with the exact gasket. If they call for dry installation, do not add a bead of RTV as extra insurance. If they specify sealant, use the specified type and placement. No vehicle, engine, gasket design, or service procedure is given here, so a universal dry-versus-RTV instruction or torque figure would not be reliable.
How to apply Permatex item 22071 when RTV is specified
Permatex gives the following directions for item 22071. They apply to this product; the vehicle’s service information still governs the assembly sequence and tightening torque.
Rank #2
- Compatibility: Specifically designed to fit all Chevy SB & BB Engines, covering models including 265, 283, 305, 327, 350, 383, 396, 400, 427, 454, 472, and 500 (please verify vehicle service type/model before purchase).
- Material: From high-quality 1/8" aluminum and silicone, the thermostat housing gasket boasts rust-proof, waterproof, and durable properties, withstanding harsh compartment environments.
- Installation: Features easy and secure installation, adheres to original equipment (OEM) standards, is reusable, and requires no additional sealant.
- Package Included: Each package contains 1 thermostat housing gasket ensuring reliable sealing performance for normal equipment operation.
- Function: The silicone component enhances fastening contact area, effectively sealing surface irregularities between the intake manifold and water outlet housing to prevent coolant leakage.
- Prepare the surfaces: Clean and dry the mating surfaces as directed by Permatex.
- Apply the bead: Lay an even, continuous 1/8-inch bead around the bolt holes.
- Assemble promptly: Assemble the parts immediately after applying the bead. Avoid overtightening; use the vehicle’s specified torque and sequence rather than estimating.
- Allow it to cure: Permatex specifies 24 hours for full cure. Follow the vehicle instructions for when the cooling system may be refilled or the vehicle returned to service.
See the item 22071 product directions for the product’s complete instructions.
Why excess RTV can cause problems
A bead that squeezes inward can enter an oil or coolant passage and restrict or block flow. Fel-Pro specifically warns about this risk. Fel-Pro guidance on RTV silicone gasket maker. More sealant is not a sound substitute for the correct gasket, clean mating surfaces, or the specified installation procedure.
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Rank #3
- Fitment: Thermostat Water Neck Housing Gasket for Chevy SBC BBC Engines Including 265 283 305 327 350 383 396 400 427 454 472 500
- Easy Installation: Reusable, easy to install and firm, no sealant required.
- Good Quality: Made of good aluminum and silicone, rust proof, waterproof and durable.
- Features: Silicone gasket increases the fastening contact area, the sealing effect is good, and the leakage is prevented.
- Package included: 1 x Thermostat Housing Gasket
What if the thermostat housing flange is warped or corroded?
Do not automatically try to compensate for a damaged flange with a thicker RTV bead. Inspect the sealing surfaces and address them as the vehicle procedure requires. Fel-Pro describes a rigid-carrier, molded-rubber water outlet gasket intended for certain warped or corroded flange conditions, but that design is not a universal fix. Verify that the gasket or water outlet fits the exact vehicle and engine before installation. Fel-Pro water outlet gasket information.
Quick Recap
Best Value
- Material: The Engine Coolant Thermostat Housing Gasket Made of A 1/8" good aluminum & silicone, no sealant required, housing. Reusable, rust proof, waterproof.
- Fitment: Engine Coolant Thermostat Housing Gasket Compatible with Chevy SB & BB Engines, including 265 283 305 327 350 383 396 400 427 454 472 500 engines.
- Easy Installation: Easy to install and firm, Original equipment parts standard, the sealing effect is good, can help you solve problems in time.
- Function: Silicone gasket increases the fastening contact area, seals surface between intake manifold and water outlet housing. The leakage is prevented.
- Package included: You will receive one Thermostat Housing Gasket, Please check the Vehicle Service Type before purchasing to ensure fitment.
Rank #4
- Includes 1 (One) Engine Coolant Thermostat Housing Seal
- Fits list of vehicles in image gallery fitment chart
- Exceptional Quality and Performance: This OE replacement engine coolant thermostat housing seal is designed to meet, if not exceed, the performance and quality standards of the original equipment installed on your vehicle. Experience the same high-level performance as your original parts with this engine coolant thermostat housing seal.
- Direct Replacement, No Fuss: This OE replacement engine coolant thermostat housing seal is meticulously designed for your specific vehicle's make and model, promising a direct fit. Installation is as straightforward as it gets - no fuss, no complications. Experience a seamless replacement process, made to match the original part perfectly.
- Perfect Compatibility: Compatibility is key. Make sure to check our product specifications (in image gallery) to confirm that this OE replacement engine coolant thermostat housing seal matches your vehicle's requirements. Get the perfect fit and optimal performance every time with our replacement parts.
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