OIL PAN GASKETS

AVOIDING DROPS ON THE DRIVEWAY

Oil Pan Gasket Function
Oil pan gaskets come in all shapes, sizes, and designs. They range from the low cost cork-rubber parts, to some ultra-sophisticated molded rubber parts. Some have steel reinforcement, while others have plastic. But they all serve the save purpose; to prevent leaks between the engine block and oil pan.

Oil Pan Gasket Materials and Designs

Although oil pan gaskets are serve the same purpose, many different sealing solutions are needed because there is such a wide variety of OE oil pan designs.
Here are just some of the oil pan types:

CORK-RUBBER OIL PAN GASKETS
Many years ago, most automobile oil pan gaskets were made of plain cork. This material was generally hard, brittle, and dried out fairly quickly. Years later, rubber was mixed in, and the modern cork-rubber material was born. Various rubber polymers could be used to change the performance characteristics of the material, depending on the fluid to be sealed, bolt load, and temperature requirements.

Cork rubber conforms and seals to thin, sheet metal covers, but relaxes quite a bit over time, so the bolt torque loss is pretty high. Near the end of its useful life, it begins to seep oil. To minimize these problems, premium grade material is required, like the cork-rubber material specified by Magnum for conventional gasket applications.

MOLDED RUBBER OIL PAN GASKETS
In the 1990's, as demand grew for 100% dry sealing, OEM engines designs that accepted molded rubber gaskets became more common. High temperature, automotive grade silicone is the most frequent choice of material.

Precision molding rubber is a science that is far beyond the ability of old fashioned, low cost "gasket cutters" to develop. Their business began a long slide downward. The design and manufacture of molded rubber products has been a specialty of Magnum's manufacturing facility for many years. Magnum's brand name for these gaskets is "Magnum MaxDry".

Molded rubber gaskets have proven to be very reliable. Rubber, being a solid, oil or coolant can't wick through it like on other porous materials. In order for a fluid to leak, it must go over or under the gasket, and with proper design and manufacturing, that won't happen.

MOLDED RUBBER-ON-CARRIER OIL PAN GASKETS
Unsupportedmolded rubber gaskets are "floppy" and require careful handling and installation. OEM designs moved toward gaskets with rubber sealing beads molded onto rigid carriers. Magnum's oil pan gaskets with nylon composite or aluminum carriers are called "Magnum MaxDry SS" (Super Sealing).

Oil Pan Gasket Disassembly

As with any gasket joint disassembly, look for any leaks or external damage before removing the oil pan. If the pan is being removed specifically to repair a leak, double-check and triple-check to make sure it's really the culprit. There are many potential sources of leaks higher on the engine that may be hard to see but end up running down on the oil pan. Be especially suspicious if it is a high volume leak, which is more like to come from a rear main bearing seal, a timing cover seal or an oil pressure sending unit.

Oil Pan Gasket Assembly

First of all, the general rules of gasket installation must be followed; that is prepare clean, dry surfaces, and be sure that oil pan flanges are flat and straight.

On older models with cork-rubber rails and rubber end seals, small dabs of quick drying gasket or weatherstrip adhesive should be used to hold gaskets in place on the engine block. Dabs of RTV silicone can be added at corner joints where side rail gaskets and end seals meet. DO NOT APPLY EXCESSIVE AMOUNTS OF RTV or it will drop into the oil pan and cure - then the next thing you know, it's sucked onto the oil pickup screen and starving the engine for oil!

Molded rubber and molded rubber-on-carrier gaskets should have features that mate with block or pan features to securely hold the gasket during assembly.

Some applications use what are called "Press-In-Place" gaskets. In this case, there is a groove provided in the molded or cast cover, and the rope-like gasket is pressed in place. When installing PIP gaskets, don't start in one place, and work your way around. Every time you push the gasket into the groove, it grows (stretches) a little. By the time you get all the way around, you could have several inches of gasket hanging out. Instead, begin installing the gasket at the ends, then tuck in the middle, followed by tucking in the gasket between the ends and middle, a little at a time. You wouldn't torque a head or manifold by starting at just one end would you? The same logic applies here.

When is an oil pan gasket more than an oil pan gasket?

As oil pan gasket design and manufacturing becomes more sophisticated, it creates an opportunity to integrate gaskets into the design of other engine components. A perfect example is Magnum's MaxDry SS gasket for the GM 3.8L V6. In this case, the gaskets is integral with an oil pan windage tray.

Further, the Magnum gasket/windage tray features taller sealing beads on both sides of the tray's gasket flange. This is in contrast to the OE service gasket, which has no sealing bead on the pan side, instead calling out the use of RTV.






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