The last time I went to change my oil, I noticed a small drip of oil coming from the drain plug. I didn't think much about it. I just changed the oil and forgot about it. I never saw a spot of oil under the car, and I never have to add oil between the 5,000 mile oil change interval I'm currently following.
Yesterday I changed my oil and noticed that the slight drip of oil was there on the plug again. After draining the oil and looking at the factory drain plug, I found that the washer on the OEM drain plug is really thin. Probably too thin to do anything meaningful. So I headed up to AutoZone and picked up a $4 assortment of M14 drain plug washers. While I was there, I saw that that they had a magnetic drain plug that fit the Mirage, so I went ahead and picked one up for $5.
So here's a look at the new and original drain plugs...
The assortment of washers had just about anything you would want to try: copper, nylon, steel, and steel with rubber. I decided on the steel with rubber washer (pictured below)...
Everything went together easily...and after 24 hours, no drip on the new plug.
The size of the drain plug is M14-1.50.
The size of the washer is M14.
Here are the AutoZone part numbers:
M14-1.50 Magnetic Drain Plug...Part # 652166
M14 Drain Plug Gasket Assortment...Part #653336
Note: I didn't like the gasket that came with the magnetic drain plug, so I bought the gasket assortment so I could use the steel/rubber gasket/washer.