RTV Gasket Maker — How to avoid common gasketing mistakes

How to use RTV gasket maker

RTV gasket maker products are available in many variations, from products for high temperature applications to products that can be applied and the vehicle put back into service after just 1-minute. So choose the material based on its use and how long you’re willing to wait for the product to cure before you can install new fluids. For engine applications like valve covers, oil pans, etc., make sure you buy an RTV product rated for high-temperatures.

The RTV bead application instructions show here are the same for 1-minute cure, 90-minute, and 24-hour cure. But the assembly and final torque instructions are only for longer curing products.

Prepare the surface before applying RTV gasket maker

Surface preparation is key. Make sure the surfaces you are sealing are clean, dry, and free of any old gasket material or residue.

New silicone gasket maker will not adhere to old cured silicone gasketing materials. You must remove all traces of old silicone. Use a chemical gasket remover if you can’t remove the old gasket/sealer using a non-marring scraper.

After removing the old RTV, clean the surface with brake cleaner and allow to dry before applying any the product.

Apply a thin bead

Apply the RTV in a continuous even bead, making sure to seal the entire joint or seam you are working on. It’s better to apply a little too much than too little.

Use the RTV sparingly! More is NOT better. Using too much gasket maker will actually cause leaks. In addition, extra RTV material can break off and block oil coolant passages.

The Optimum bead size is 1/8″ – 1/4″ diameter

Assemble but don’t final torque — wait to cure

Unless you’re using a 90- minute cure or a 1-minute cure gasket maker, you must allow proper curing time before final torque.

Here’s the procedure: Apply the bead of RTV. Assemble and install fasteners hand tight. Allow to sit for one hour. Then final torque.

Refer to the instructions before filling with fluids

Some gasket makers require a full 24-hours before coming into contact with oil and fluids. Filling before that time can result in leaks.

Avoid these common RTV gasketing mistakes

©, 2022 Rick Muscoplat