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Product Feature: Hi-Temp (Red and Blue)

Posted by Content Cucumber on

Silicone sealant is one of the best sealants on the market. It has a high resistance to most climates, provides a strong seal, and is waterproof. But when it comes to sealant used on vehicles where gaskets are exposed to extremely high temperatures, a special kind of sealant is used: Hi-Temp RTV Silicone Sealant. This specialty sealant is easy to apply and much stronger than other sealing materials.

What is Hi-Temp RTV sealant?

The RTV in RTV Silicone Sealant stands for room temperature vulcanizing sealant. Vulcanization is the chemical process of hardening both natural and synthetic rubbers. Hi-temp RTV sealant has several very attractive advantages over other kinds of sealants. These characteristics include:

Easy to use and apply

Light viscosity, enabling good flow

No issues with shrinkage


Temperature resistance

Acid and alkali resistance

Long lifespan

The biggest selling point of hi-temp silicone sealant is its temperature resistance. Most hi-temp RTV silicone sealants can withstand temperatures of up to 400 degrees fahrenheit. Silicone Depot’s Hi-Temp RTV Silicone Sealant can handle intermittent exposure to temperatures up to 650 degrees.

Hi-Temp sealant is versatile

Automobiles are the most common application of hi-temp silicone sealants. Since a car’s engine typically hits about 200 degrees fahrenheit, heat resistant sealant is not only ideal, it’s necessary if you don’t want gaskets blowing off on the middle of the highway.

Engine gaskets within forced induction systems typically require hi-temp sealant. Hi-temp silicones are also popularly used on oil pump seals, fuel pump covers, and timing chain covers. Axle housings and other valve covers are also ideal locations for hi-temp silicone sealant.

Industrial applications also require hi-temp silicone sealants. Gaskets on compressors, appliance doors and furnaces are prime examples. Ductwork may also call for temperature resistant sealants as do furnace door gaskets because of the frequent exposure to heat.

Don’t rush it

Silicone sealant is a wonderful product, but even the best of sealants aren’t instantaneous. You can do damage to your gaskets or risk the integrity of the seal if you try to use your vehicle immediately after applying your sealant. Every sealant is a little different, so be sure to read the instructions carefully to get the best results.

Silicone sealant is more complex than other sealants, and so takes longer to be ready. Most silicone sealants dry quickly, but need an additional day to fully cure. Hi-Temp silicone sealant may take even slightly longer, so be sure you plan ahead and apply your sealant well before you need to use your vehicle. There are a few other factors to consider when waiting for your sealant to cure.


Hotter temperatures result in a faster cure process. Conversely, a cure job will take longer during the wintertime.


Surprisingly, humidity is also good for silicone curing. Those living in more arid climates may have a slightly longer wait.

Proper application

Before applying the sealant, make sure the surface is clean and dry. Temperatures is not much of an issue, as silicone sealant can be applied in any climate without serious complications. However, if it is cold enough to frost or freeze over, be sure all surfaces have been properly wiped down to ensure a good seal.

Always wear eye protection and gloves. Avoid getting the sealant on your skin and be sure to store it in a safe, dry place out of the reach of children and pets. Silicone sealant should never be mixed with other chemicals. Clean with warm water any application materials immediately after use. Silicone itself is not a toxic chemical, but many sealants add secondary chemicals to keep the silicone in a liquid form before application, which can be irritating. Sealant should never be ingested or come in contact with your eyes.

Sometimes less is more

It can be tempting to lather on a large quantity of sealant, thinking that the more sealant is applied, the stronger the hold will be, but this isn’t true. If you apply pressure directly after laying down your bead of sealant, the sealant will spread out in a thin but strong layer that is more than capable of sealing strongly.

Sealant is not like glue, where excess materials can be easily wiped off with no ill effect. If too much sealant is used, some of it may leak out past the edges and actually weaken the seal. This can be especially problematic in car engines as grime, dirt and oil may catch on the exposed sealant, weakening the gasket overall and leaving it susceptible to damage.

Figuring out the perfect amount of sealant to put on a gasket can take a little practice, but around 1/8 inch is a good starting place. When you apply the sealant, make sure all holes are encircled on all sides.

Browse our selection of high-quality silicone sealant at Silicone Depot!