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The Repair Environment

When you work on an engine in the aftermarket repair environment, you never know what you’re going to find when you take things apart. Fortunately, Fel-Pro® builds gaskets for the repair environment – but what exactly does that mean?

After an engine has idled hundreds of hours, experienced thousands of heat cycles and driven tens or even hundreds of thousands of miles, the pieces that come apart will surely not be in like-new condition. The finish of sealing surfaces or molded components can change due to corrosion or scrubbing (the back-and-forth movement of components as they expand and contract at different rates due to material differences). If a gasket or seal has failed, combustion gasses, corrosive fluids and external contamination can further worsen the condition of these surfaces.

The gaskets and seals designed to seal new components are no longer ideal, and may not be able to seal reliably in the repair environment.

Fel-Pro accounts for this everyday wear-and-tear in every gasket they make, whether it’s with the specialized coating on PermaTorque® MLS head gaskets that improves sealing on less-than-perfect surface finishes or by manufacturing gaskets to accommodate machine work such as decking / milling or cylinder overbore.

Another way Fel-Pro solves problems in the repair environment is with PermaDryPlus® (PDP) gaskets. We’ve highlighted PDP gaskets in terms of resistance to corrosive coolants before, PDP gaskets also solve problems when coolant is not involved. Intake manifold gasket set MS 98016 T (all PDP gasket sets use a T-suffix in the part number) fits 1999-2015 GM 4.8L / 5.3L / 6.0L / 6.2L LS-based truck engines with cathedral intake ports – engines that work hard, often in demanding environments and conditions.

These engines utilize a plastic intake manifold, with plastic carrier-style intake manifold gaskets as original equipment, but these gaskets are not exposed to coolant. Different issues arise in these applications – over time, corrosive air fuel mixtures break down the gasket carrier and the sealing beads of the OE gaskets, and the plastic manifold can warp from heat cycles. Any of these can result in a vacuum leak, CEL / MIL illumination – specifically P0171, P0174 and / or P0300 codes and other drivability issues.

Let’s look at each issue with the OE gaskets and manifold in the repair environment, and see how Fel-Pro addresses each.

The OE and OE-style plastic intake manifold gasket carrier can crack or degrade due to heat cycles and / or corrosive air-fuel mixtures:


Leaking OE intake gaskets on the OE intake manifold

Fel-Pro PermaDryPlus intake manifold gaskets utilize an aluminized steel carrier that will not crack or break down. Heat cycles will not make the metal brittle like the OE plastic, and the metal carrier is unaffected by air-fuel mixtures, even when highly corrosive ethanol-blended fuels are used. This metal carrier also incorporates locating tabs that hold the gasket in place on the cylinder head by slipping over the head bolts. This is a more durable solution than the OE plastic clips that hold the gaskets to the intake manifold and can break, especially if the gasket needs to be removed once clipped to the manifold.

The OE and OE-style sealing bead design can easily be over-compressed and can deteriorate due to exposure to fuel:


OE sealing beads have broken down due to fuel exposure

The molded rubber sealing beads found on PDP intake gaskets are manufactured in-house using Fel-Pro’s proprietary Fluoroelastomer (FKM) molded rubber compound. This FKM rubber resists all automotive fluids, including harsh fuels, preventing sealing bead breakdown. The enhanced bead design and superior material properties of the FKM molded rubber ensures a proper seal is maintained, even when the sealing surfaces are less-than-optimal. Remember, RTV silicone or other sealants should never be applied around ports or to sealing beads, as it will interfere with the proper compression of the sealing beads.

The OE intake manifold can warp due to thermal cycles. This is especially likely on higher-mileage or commercial-use engines.


Light visible between straight-edge and port sealing surfaces indicates manifold warpage

The MS 98016 T gaskets are engineered with this aftermarket condition in mind, and the molded rubber sealing beads are designed to accommodate a slightly warped manifold. FKM properties come into play again, allowing these gaskets to seal even when the manifold is slightly warped.


Fel-Pro® PermaDryPlus® problem-solving intake gaskets

This problem-solving philosophy can be found all throughout Fel-Pro’s product offerings. You can trust Fel-Pro to provide gaskets with the technology needed to get the job done right, especially when the going gets tough.

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