Gasketing

Repco offers a comprehensive gasketing range designed to suit everything from quick repairs to full engine rebuilds. Whether fitting a new water pump, resealing a rocker cover, or assembling a differential, the right gasket sealant helps prevent leaks and maintain correct clamping pressure. Our range includes trusted gasket maker products, flexible rtv silicone options for high temperature areas, and specialised rtv sealant formulations for oil, coolant, and general automotive use. With reliable gasketing solutions available, you can approach sealing jobs with confidence and achieve consistent, professional results every time.

Correct sealing is essential when working on engines, gearboxes, cooling systems, and exhaust components. Gasket sealant helps prevent leaks of oil, coolant, fuel, and exhaust gases by filling minor surface irregularities between mating components. Whether used alongside a conventional gasket or as a liquid gasket in place of one, selecting the right gasket sealer improves reliability and reduces the risk of repeat repairs.

Modern engines often rely on precise tolerances and specific sealant types, including rtv silicone, anaerobic compounds such as Loctite 515 and Loctite 518, and specialist products like Permatex aviation form a gasket. Using the correct gasket maker for the job ensures compatibility with temperature, pressure, and fluid exposure.

Should you use sealant on gaskets?

Sealant should only be used where recommended by the vehicle manufacturer. Many modern pre-formed gaskets, including multi-layer steel head gaskets and moulded silicone gasket designs, are engineered to be installed dry. Adding gasket glue or excess liquid sealant in these cases can interfere with clamping force and sealing performance.

However, some applications benefit from a thin, even layer of gasket sealant. Older engines with stamped steel rocker covers or pressed oil pans often have minor surface imperfections. A light coating of Permatex gasket sealant, Permatex ultra black, or Permatex ultra grey can help create a reliable gasket seal by filling small scratches and gaps.

When resealing components such as timing covers, thermostat housings, and water pumps, always check workshop manual specifications. Over-application can cause excess material to squeeze into oil galleries or coolant passages, potentially leading to blockages.

What is a gasket sealant?

A gasket sealant is a compound formulated to prevent leaks between two mating surfaces. It may be used with a traditional paper, cork, rubber, or composite gasket, or it may function as a liquid gasket on its own.

Common types include:

• RTV gasket maker, which cures at room temperature and forms a flexible seal.
• Anaerobic sealants such as Loctite 515 and Loctite 518, which cure in the absence of air between metal surfaces.
• Aviation gasket sealant, including Permatex aviation form a gasket, which remains tacky and resists fuel and oil.
• Spray sealant products such as copper gasket spray or hylomar spray for thin, uniform coatings.

Each type has specific temperature ratings, chemical resistance properties, and curing times. High temperature silicone and heat resistant silicone products are often rated beyond 300°C, making them suitable for engine components. Exhaust gasket sealant and exhaust gasket maker products are formulated to withstand even higher temperatures found in exhaust systems.

What is the best thing to seal a rubber gasket with?

The best product for sealing a rubber gasket depends on fluid exposure and temperature. For oil-exposed areas such as rocker covers and sump pans, an oil-resistant rtv sealant or fuel resistant sealant is appropriate. Products like Permatex ultra black are designed for maximum oil resistance and flexibility.

Where close-fitting machined metal surfaces are involved, an anaerobic Loctite gasket sealant such as Loctite 518 may be preferable. These products cure in the absence of oxygen and are suited to rigid flanges without significant movement.

High temperature silicone or high temp silicone variants are useful around thermostat housings and coolant outlets, where heat and coolant contact occur. Always confirm compatibility with the gasket material, as some silicone gasket materials can degrade if exposed to incompatible chemicals.

Avoid substituting unrelated adhesives such as carpet adhesive in automotive sealing applications. These products are not designed to withstand oil, fuel, or engine heat.

What is the difference between normal and RTV silicone?

RTV silicone stands for Room Temperature Vulcanising silicone. It cures at ambient temperature to form a flexible, durable gasket seal. Automotive rtv silicone and rtv gasket maker products are specifically formulated to resist oil, coolant, and vibration.

General-purpose silicone products, often used in household applications, may not provide the same resistance to petroleum products or sustained engine temperatures. Automotive high temperature silicone can typically withstand continuous temperatures above 250°C, with some heat resistant silicone products rated even higher for intermittent exposure.

RTV sealant also differs in curing chemistry. Some formulations release acetic acid during curing, while others are neutral cure. In automotive use, neutral cure or sensor-safe formulations are recommended to prevent corrosion and avoid damage to oxygen sensors.

Where would I use gasket sealant on my car?

Gasket sealant is commonly used in the following automotive applications:

• Rocker cover gaskets
• Oil pan or sump gaskets
• Timing cover assemblies
• Water pump installations
• Thermostat housings
• Differential covers
• Intake manifold end seals

Exhaust gasket sealant or exhaust gasket maker may be used on certain flange connections, provided it is rated for high temperature silicone performance. Copper gasket spray is often applied to head gaskets in specific performance or restoration contexts, where manufacturer guidelines permit its use.

Before applying any liquid gasket or gasket sealer, thoroughly clean both mating surfaces. A gasket remover helps eliminate old material without damaging metal surfaces. Ensure the area is free of oil, coolant, and debris. Apply a continuous, even bead where required, and allow the recommended skin time before assembly.

Practical Advice for Reliable Sealing

Successful sealing depends on preparation, product selection, and correct torque procedures. Tighten fasteners in the specified sequence and to the recommended torque setting to ensure even clamping pressure. Allow sufficient curing time before refilling with oil or coolant, particularly when using RTV gasket maker or high temperature silicone products.

By selecting the appropriate gasket sealant, whether Permatex gasket sealant, Loctite gasket sealant, or a specialist aviation gasket sealant, and applying it carefully, you can achieve durable, leak-free results across a wide range of automotive repairs.

Finish the Job with the Right Supporting Gear from Repco

Using quality gasket sealant or rtv silicone is only part of a successful repair. Repco also stocks products from the tools and garage equipment category, helping ensure correct torque application and safe vehicle support during installation. The oils and fluids range provides engine oil, coolant, and transmission fluids needed after components have been resealed. For thorough preparation, workshop consumables such as gasket scrapers, cleaning sprays, gloves, and rags help create clean mating surfaces before applying gasket maker or rtv sealant. Pairing the right sealing product with proper tools, fresh fluids, and careful preparation supports long term reliability. With a practical approach and the right gear on hand, sealing tasks across the engine, drivetrain, and cooling system can be completed efficiently and to a high standard.