my printer is making a loud grinding or crunching noise when it tries to print.

Diagnosis

The loud grinding or crunching noise in a Canon PIXMA MG3620 is almost always caused by a mechanical obstruction in the carriage path or a failure in the timing belt system. When the carriage motor attempts to move the printhead assembly across the platen, it encounters resistance. Because the motor is geared to move at a specific speed, it continues to spin against the obstruction, causing the plastic gears to slip or the rubber belt to skip teeth, which creates that characteristic "crunching" sound. This typically happens due to a "micro-jam"—a small piece of torn A4 or letter paper that has ripped off during a previous jam and is now lodged in the far right "parking" station or the far left limit switch. Alternatively, foreign objects like paper clips, staples, or accumulated dust clumps can fall into the track. You can confirm this by attempting to move the carriage manually while the power is off; if you feel a hard stop or a "catch" before the carriage reaches the end of the rail, there is a physical blockage.

How to Fix It

Follow these precise steps to clear the obstruction and reset the carriage mechanism:

1. Power down the printer immediately and unplug the power cord from the wall outlet to prevent the motor from engaging while your fingers are inside.
2. Lift the scanner unit (the top lid) and open the risk-access cover to expose the printhead carriage.
3. Check the far right side of the printer (the home/parking position). Use a flashlight to look for small scraps of paper or debris lodged in the cleaning station wipers.
4. Gently grasp the printhead carriage. If it is locked in the home position, apply light pressure to move it toward the center. If it resists, do not force it; use a pair of tweezers to remove any visible debris from the track first.
5. Once the carriage is centered, slide it slowly to the far left and then back to the far right. It should glide smoothly without any clicking or jumping.
6. Inspect the clear plastic encoder strip—the thin, translucent ribbon that runs horizontally across the width of the printer behind the carriage. If there is a smudge of ink or grease on this strip, the printer may "hunt" for its position and crash into the side, causing the grinding noise. Gently wipe it with a dry, lint-free microfiber cloth.
7. Close all covers and plug the unit back in. Perform a power cycle by holding the power button for 5 seconds.

If That Didn't Work

• Check the Paper Feed Tray: Sometimes the grinding isn't the carriage, but the paper pick-up rollers struggling with a jammed sheet. Open the rear tray and use a can of compressed air to blow out any debris from the feed mechanism. Ensure the paper guides are snug but not overly tight against the stack.
• Inspect the Carriage Belt: Look at the black rubber timing belt connecting the motor to the carriage. If you see frayed edges or a gap where the belt has slipped off the pulley, the motor will spin uselessly and grind. If the belt is snapped, the carriage assembly must be replaced.
• Clear the Rear Access Door: Open the back of the printer to ensure no paper is jammed in the output rollers. A piece of paper stuck in the rear duplexing area can put tension on the entire chassis, preventing the carriage from moving freely.
• Reset the Encoder Strip: If the noise persists, the encoder strip may be displaced. Ensure the strip is tensioned correctly and not sagging. If it is loose, the carriage will move erratically and hit the side walls.

Heads Up

• Never use oil or WD-40 on the carriage rails; the MG3620 uses a dry-glide system, and lubricants will attract dust, creating a sludge that will eventually seize the motor.
• Always turn the printer off before manually moving the carriage to avoid damaging the stepper motor or triggering a "Carriage Error" code.
• Avoid using overly thick cardstock (above 200g) in the rear tray, as this often leads to the "micro-jams" that cause these grinding issues.
• If you see a "5100" error code on the screen, this is the specific system code for the carriage being unable to move; it confirms a mechanical blockage.