Some Dos and Don'ts When Searching for a Rear Main Seal Replacement
With a damaged seal, your crankshaft is exposed to unwanted leaks. Keeping the rear main seal in its top form is a must to keep the oil inside the engine as the crankshaft rotates. Need a replacement now? Check out this guide to make shopping for parts fast and hassle-free.
What You Should Do
Make sure you know the specs of your vehicle before shopping: year, make, and model; engine and crankshaft design; and its type of rear main seal. You should also know the rear main seal design: does your crankshaft require one-piece or two-piece seals. Refer to your owner's manual for detailed information.
- Perform a little research about the rear main seal so you can make a guided decision.
Rear Main Seal Types:
- Rope Seal- If you have a vintage auto, it is likely that you'll be getting this seal type. Rope seals are commonly used in old engines. Similar to cords, these seals keep pressure within the engine. However, these get easily soaked in oil so they are prone to early wear and tear.
- Split Seal- This type of seal is common in modern vehicles. It is an improved version of the rope seal; it is more durable because it is made of rubber and its design protects more area.
- One-piece Seal- The toughest seal among the three types, a one-piece seal provides the tightest coverage. It is usually used in heavy-duty engine blocks and racing applications. Unlike the rope and split seals, one-piece seals require a specially machined crankshaft and replacement of the stock crankshaft.
What You Shouldn't Do
- Don't base your choice on price alone.
Rear main seals are relatively cheap; you can get seals for as low as $15. However, it is important to take note of the reason why they are cheap (i.e. type, material, and added features) before buying.
For example: Let's take a look at Felpro's line of products.
- Seals that cost around $15 are rope seals; they are cheaper because of their design and material.
- Felpro also offers seals that are priced at $20; these seals are a little more expensive because of their material and type.
- High-end seals that cost more than $20 are usually crafted from Viton; these are more resistant to heat making them perfect for racing applications and heavy-duty vehicles.
The added features and different material types affect the price of the seals. Instead of focusing on the number, check out the added features to see if it's worth spending on.
Auto Repair 101: Replacing the Rear Main Seal
If your ride is already due for an oil change, you might want to consider changing the rear main seal as well, so you can save time and effort. This seal protects your vehicle against unwanted leaks in the system; replacing it regularly will help ensure top-notch auto performance and fuel efficiency. If you're wondering how to go about it, here is a quick guide to help you out.
NOTE: This instructional guide can only be used for vehicles with two-part seals. Doing this task is also easier if you have an assistant.
Stuff you'll need:
- Replacement rear main seal
- Shop towel
- Floor jack
- Oil and coolant drain pans
- Blue RTV silicone sealer
- Brass punch
- Putty knife
- Pry bar
- Slide hammer
- Bungee cord
- Blocks of wood
- Brake cleaner
- Needle nose pliers
- Park your vehicle on a level surface and lift it using your jack stands. Before you start the replacement, pressure wash the area under the engine using soapy water and drain the radiator. Leave it to dry.
- Locate the engine block under the hood and disconnect the battery cables, throttle linkages, and wiring connectors (starter, backup switches, solenoids, sensors, speedometer cable, etc.).
- Remove the oil pan bolts using the putty knife followed by the rear bearing cap bolts, flywheel cover, torque converter bolts, engine mounting bolts, etc. until you see the crankshaft. Locate the rear main seal.
- Use the small brass punch to take out the upper part of the seal; tap it towards the direction of the crankshaft's rotation while your assistant turn the engine over by hand. If it has a wire at the center, tap the wire and grab it using the pliers. Use the insulated gauge wire to push the seal while pulling the wire out.
- Clean the side of the seal that goes into the block using soap and lubricate the other side that fits the crankshaft. Push it into the hole of the crankshaft while rotating the crankshaft to the same direction. The lip should face the front part of the engine.
- Grab the socket and press the neoprene and rope seal on the main cap. Apply a thin coating of the RTV sealer on the cap-to-block mating surface, but fill the side cavities with the sealer. Tighten the cap bolts and make sure you follow the proper torque measurements. (Refer to the owner's manual if you are unsure.)
- Clean your oil pan and mount the new gasket. To re-install the parts you took out, follow the steps in reverse.