Stupid question, I know. But I'd like to know for sure before I remove the plastic rock guard thing to drain it.

I've never drained it on an oil change, and I'd like to start doing that.

Thanks

 

Yes, a rather large bolt right near where the cooler line connects. It's something like 28 or 29mm. I couldn't get it loose until I had the cooler off the car.

Good luck!

Greg O

 

The large "nut" you are referring to is the special bolt that holds the oil cooler bypass thermostat valve in place. It is not a drain and is most certainly not designed for frequent removal. There is also a thin copper gasket washer that will not withstand reuse.

The bolt is steel and the oil cooler is aluminum. Frequent removal without proper precautions will result in galled threads and a leak at best, and most likely a ruined oil cooler.

There is no reason to drain the oil cooler when changing the oil. There is a negligable amount of oil in the cooler. If it were necessary to drain the cooler Mazda would have made it easier to get to and furnished a drain plug there.

 

Okay, thanks for the advice, I'll leave it alone.

I guess I thought it held more than it actually did.