Diagnosis
The leakage occurring in the DeWalt DCCS620B is typically caused by the gravity-fed design of the bar and chain oiling system. Unlike the motor, which is sealed, the oil reservoir uses a simple flow-through mechanism to ensure the chain remains lubricated during high-speed cuts. When the saw is stored upright or on its base, the oil sits directly against the discharge port. Because bar oil is formulated with a very low viscosity to ensure it can penetrate the chain links quickly, it can seep past the internal seals via capillary action or simple gravity. This is further exacerbated if the saw is stored in a garage where temperature fluctuations cause the air inside the reservoir to expand and contract, effectively "pumping" the oil out of the tank and onto the floor. To confirm this is the issue, place a clean piece of cardboard under the saw; if the drip is coming from the area where the bar meets the chassis rather than the battery compartment, it is a standard oil bleed. If the oil is thick and smells like burnt electronics, you have a catastrophic motor seal failure, but in 95% of cases, it is simply the lubrication system venting.
How to Fix It
To stop the leaking and preserve your workspace, follow these specific storage and maintenance steps:
- Drain the Reservoir: If you are not planning to use the saw for more than a week, empty the bar oil tank. Unscrew the oil cap and tip the saw carefully to pour the remaining oil into a waste container.
- Clean the Discharge Port: Use a compressed air can or a stiff nylon brush to clear any sawdust or wood chips from the oiling hole located at the base of the guide bar. Debris here can create a "wick" that pulls oil out of the tank even when the saw is off.
- Correct Storage Orientation: Never store the DCCS620B standing vertically on its handle or flat on its bar tip. Instead, lay the saw on its side. Position it so the oil tank cap is facing upward and the guide bar is parallel to the ground. This moves the oil level away from the discharge port.
- Seal the Cap: Ensure the oil cap is threaded correctly and tightened firmly. A cross-threaded cap will allow air to enter, which pushes oil out through the bottom of the unit.
If That Didn't Work
- Inspect the Bar Oil Pump: If the leaking is excessive (more than a few drops per hour), the internal oil pump seal may be compromised. Remove the guide bar by loosening the mounting nuts and inspect the oil delivery hole for any visible cracks or rubber gaskets that have perished. If the seal is torn, the entire oil pump assembly must be replaced.
- Check for Overfilling: Ensure you are not filling the oil reservoir to the absolute brim. Leave approximately 1/4 inch of headspace at the top of the tank. Overfilling creates excessive internal pressure that forces oil out of the delivery system.
- Switch Oil Viscosity: If you are using a generic "all-purpose" thin oil, switch to a high-quality, tacky bar and chain oil specifically designed for cordless saws. Thicker, tackier oils are less prone to seeping through the seals during static storage.
- Verify Bar Installation: Ensure the guide bar is seated perfectly flush against the chassis. If the bar is slightly crooked, it can create a gap in the oiling port, allowing oil to leak externally rather than flowing down the bar.
Heads Up
- Avoid Solvent Cleaning: Never use gasoline or harsh chemical degreasers to clean the oil tank area, as these can degrade the rubber seals and cause permanent leaks.
- Battery Safety: Always remove the 20V Max battery before performing maintenance or cleaning the oil leak to prevent accidental trigger engagement.
- Bar Maintenance: Every 5-10 uses, remove the bar and clean the oil groove with a thin piece of plastic or a wire to prevent "oil backup," which forces lubricant to leak out the bottom.
- Storage Temperature: Avoid storing the saw in areas where temperatures drop below freezing, as the oil can thicken and then leak unpredictably when the garage warms up.