Parts for your 2010 Mazda 6-Sump plug washers

2010 Mazda 6 sump plug washers — do they use one, and why it matters

Yes, the 2010 Mazda 6 uses a sump plug washer (also called an oil drain plug gasket). Technical sources confirm it’s a replaceable crush washer on the drain plug: the Mazda 6 (GH, 2008–2012) Workshop Manual, Engine Oil Replacement procedure, instructs refitting the drain plug “with a new washer” and torquing the plug correctly, the Mazda Electronic Parts Catalogue lists a 14 mm oil plug gasket (Mazda part number 9956-41-400) for GH-series Mazda 6, and the Haynes Mazda 6 Petrol & Diesel (2007–2012) manual also notes renewing the sealing washer whenever the plug is removed. Typical drain plug torque for these engines is 30–41 N·m with a new washer installed.

For the 2010 Mazda 6, that small crush washer is doing a big job. It’s designed to deform slightly under torque to seal the gap between the drain plug and the alloy sump, keeping engine oil where it belongs through heat cycles, vibration, and pressure changes. Because it crushes to form a one-time seal, Mazda and most service manuals recommend replacing it at every oil change rather than reusing the old one. It’s cheap insurance against weeps and drips that can leave spots on the driveway or, worse, slowly drop the oil level.

Most 2010 Mazda 6 models (petrol and diesel) use a 14 mm aluminium crush washer on an M14 drain plug. Genuine Mazda part numbers commonly supplied for this generation include a 14 mm gasket such as 9956-41-400, with plenty of equivalent aftermarket options in aluminium or copper. Aluminium is typical from factory and seals nicely at the specified torque range of 30–41 N·m. Over-tightening to “make it stop leaking” isn’t the fix, that risks stripping the sump threads. A fresh washer and correct torque is the proper approach.

During a service, it’s smart to have a couple of spare washers on hand. After draining the oil, wipe the sump face clean, fit a new washer to the plug, and torque it accurately. After refilling, run the engine, let it sit a minute, then check for any sign of sweating around the plug. If there’s still a weep, the mating face might have a nick or old gasket material—remove the plug, inspect, clean, and try again with a new washer. Avoid stacking two washers, and replace the plug itself if the flange is gouged. For everyday motoring in Australia or New Zealand, swapping the washer at each 10,000–15,000 km service (or annually) keeps the Mazda 6 tidy and leak-free.

• Replace the washer at every oil change
• Use a 14 mm crush washer that suits the M14 plug
• Tighten the drain plug to 30–41 N·m
• Never double up washers or over-tighten

How often should the sump plug washer be replaced on a 2010 Mazda 6?

Best practice is every oil change. The washer crushes once to form a seal, reusing it increases the chance of a slow weep. If it must be reused in a pinch, check for leaks after running the engine and replace the washer at the next opportunity.

What size and type washer does a 2010 Mazda 6 use?

It uses a 14 mm crush washer for the M14 drain plug—typically aluminium on factory parts. Genuine Mazda listings commonly reference a 14 mm gasket such as 9956-41-400, with copper or aluminium aftermarket equivalents also fine when sized correctly.

What torque should the oil drain plug be tightened to?

Torque the drain plug to 30–41 N·m with a new washer installed. Clean the sealing face, avoid over-tightening, and recheck for any signs of oil around the plug after the engine has run and the car has sat for a minute.