Why replace your engine gaskets?
In recent years, automotive engineers and service technicians around the world have used gaskets in a variety of ways. Gaskets are used to make joints fit together perfectly. Two of the most common gaskets in use today are composite gaskets and silicone (formed-in-place) gaskets.
Composite Gaskets: Composite Gaskets are combinations of cork, rubber, paper or felt, designed and cut specifically to fit individual application. They’re often applied with a gasket dressing or adhesive to aid in assembly and sealing.
Silicone Gaskets (Formed-in-Place): These gaskets are made of a silicone compound that is applied, in an uncured blend, directly to the mating parts and allowed to cure in place after assembly.
These instructions will help you replace both composite and silicone gaskets. READ the instructions completely before you begin.
TOOLS AND EQUIPMENT
TO CHANGE YOUR ENGINE GASKETS YOU WILL NEED:
- Putty knife
- Torque wrench
- Aerosol brake cleaner
- Gasket material (composite or silicone)
- Chemical gasket remover
- Straight edge
- Threadlocker (medium strength- if no lockwashers are present)
BEFORE YOU BEGIN
Proper maintenance and service procedures are vital to the safe, efficient operation of all motor vehicles, as well as to the safety of the person performing the work—you.
Whenever you are working on your vehicle, we recommend that you follow these important safety rules:
- Do have a first-aid kit handy.
- Do be careful when working around hot or sharp objects.
- Do follow the manufacturer’s instructions for all products.
- Do use safety stands under the frame or drive-on ramps if you must raise your vehicle.
- Don’t run the engine without proper ventilation.
- Don’t smoke when working around the engine.
READ these instructions completely before you begin:
Applying Silicone Gaskets
- Allow the engine to cool completely before assembly.
- Clean all mating surfaces thoroughly. Since excessive scraping with a putty knife can damage light alloy metals, use a chemical gasket remover. Flush oily parts with a residue-free brake cleaner.
- Inspect the mating surfaces of valve covers, timing covers and oil pans for dents, creases and warpage.
- For best results, apply silicone gaskets at 45-degree angles to the part, forming a 1/8-inch bead. Encircle all bolt holes.
- Assemble parts immediately. Be careful not to “squeeze out” silicone material during torquing. Always use a torque wrench where required. For best results, tighten all bolts in the proper sequence. RTV (room-temperature vulcanizing) gaskets do not need to be retorqued.
- Wait one hour to allow the silicone to vulcanize, and then operate the vehicle and check for leaks.
Applying Composite Gaskets
- Read the gasket and sealant instructions.
- Clean all mating surfaces with chemical gasket remover and scrape away the softened material. If you’re cleaning an aluminium surface, be careful not to damage it during scraping. Residue-free brake cleaner may be used as a final spray cleanup to remove debris.
- Inspect all mating surfaces. Check for flatness using a straight edge. Repair or replace any distorted bolts. If excessive warpage is present, replace the warped part.
- Apply appropriate sealant to the gasket and mount it to the cover. Sealant should then be applied to the second sealing surface of the gasket. Damaged surfaces may require additional layers of sealant to ensure a leak-free seal.
- Mount the cover and torque it to the vehicle manufacturer’s specifications using an X-pattern for a uniform clamping load. Note: For best results, apply a medium strength threadlocker to all mounting bolts.
- Operate the vehicle and check for leaks.
There are several types of sealant on the market. To choose the one that’s right for your application, consider such things as product features, ease of application, temperature range, pressure range and flexibility. Since high-temperature resistance and greater flexibility are preferable for late-model cars, silicone is a popular composite-gasket sealant.
Today’s high-performance, hot-running engines require superior sealing and gasketing products. These engines, with components of dissimilar metals with different expansion rates, can be very difficult to seal. In addition, computer-controlled engines require many sophisticated sensors, which can be contaminated by improper chemical applications. To meet the needs of these high-tech engines, today’s gasketing chemicals are “job-specific”. Each is designed for a specific job. If you have any questions about which silicone gasket is right for your vehicle, contact your local NAPA Auto Parts store or a NAPA AUTOPRO service centre.