High-temperature RTV sealants for professional engine and technical system repairs
Zollex Gasket Maker sealants are RTV-based silicones designed to replace traditional gaskets in automotive and industrial assemblies. Thanks to their excellent heat resistance, adhesion, and chemical durability, they ensure long-lasting sealing in high-stress systems.
The range includes 4 types of sealants:
🔴 RED – up to 350°C
Ideal for areas exposed to extreme temperatures and fluctuations. Suitable for use on exhaust manifolds, valve covers, and other high-heat components. Ensures reliable sealing under repeated thermal cycling.
⚙️ GREY – up to 350°C
A professional-grade universal sealant for replacing most engine gaskets. Recommended for mounting water and oil pumps, oil pans, timing gear covers, gearboxes, and other assemblies. Offers strong adhesion and excellent resistance to automotive fluids.
⚫ BLACK – up to 315°C
A multipurpose RTV with enhanced oil resistance. Commonly used for valve covers, oil pans, thermostat housings, and engine rear covers. Provides a flexible and durable seal, resistant to vibrations and thermal changes.
⚪ CLEAR – up to 260°C
A more versatile and aesthetic option. Used in moderately heated zones where visual neutrality is preferred. Ideal for dashboards, lighting assemblies, electrical housings, and low-stress engine bay components.
Key Properties:
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Resistant to oil, coolant, water, and technical fluids
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Easy to apply and non-sagging
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Neutral odor (in Neutral Odor variants)
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Remains elastic after curing
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Compatible with aluminum, steel, cast iron, plastics, glass, and ceramics
Applications:
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Engines: gaskets, covers, thermostats, pumps
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Transmissions, gearboxes
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Cooling and ventilation systems
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Industrial and household applications
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Packaging: 85g and 25g tubes
APPLICATION:
Surface preparation
Clean and degrease both sealing surfaces thoroughly. Remove all old gasket material, oil, dust, and moisture. The surfaces must be dry and clean.
Applying the sealant
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In most cases, apply the sealant to only one of the surfaces. This is sufficient if the mating surfaces are well-machined (e.g., oil pans, pump housings).
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Apply a continuous and even bead. There are two methods:
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A bead (“sausage”) line along the edge;
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Spread evenly with a finger across the surface to control thickness — particularly when applying a small amount;
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You can also form a raised center “ridge” to ensure better surface contact and effective gap filling. It effectively prevents excess squeeze-out (demonstrated in this video: YouTube).
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Avoid applying excessive sealant near internal engine cavities to prevent contamination.
Special cases:
If the mating surfaces are rough or warped (such as stamped steel valve covers or worn pans), you may apply the sealant on both sides.
Assembly
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Join the parts immediately after applying — do not let the sealant dry beforehand. This maximizes adhesion.
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Lightly tighten bolts without fully torquing them to allow the sealant to distribute properly without being expelled.
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Let the assembly sit for 1–2 hours to allow initial curing and elasticity.
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Then perform final bolt tightening to the specified torque.
Full cure
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Skin-over time: 1–2 hours
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Full curing time: 12–24 hours, depending on temperature and humidity.
ℹ️ Shelf life does not affect the quality of the sealant as long as the packaging remains intact — however, curing speed may slightly decrease over time, so for older batches it’s recommended to allow a bit more time for initial setting.