Coolant drain plug in 2000 4.0L block.
 

I have a 2000 GC 4.0L that I'm doing a coolant drain and refill on. Draining the radiator is no problem but I can't seem to find the one for the block located on the driver side behind the exhaust manifold. I thought I'd found it on my donor (same year and engine) and thought it might be similar to the drain plugs on differentials and take a simple ratchet (with no socket) to remove and reinstall but neither sizes fit in what I thought was the plug.

What am I missing here? And what socket, ratchet, etc. does it take to remove and reinstall? Or is that not an option?

Thanks in advance.

Usually between 3 & 4 just above the pan. Requires a 8mm square bit or a 5/16 allen to be modified.

Thank you, sir. Looks like I was in the right location just wrong tools.

Still missing something here. I thought I had identified the drain plug by feel from underneath - felt like it was a "screwed in" plug in the right location - but no size allen wrench, inch or metric, would fit and I don't have an 8mm square bit.

We're experiencing warmer than usual weather here in Middle Tennessee with freezing weather coming again tonight and expected to stick around a while so I went ahead without draining the block. The manual states the 4.0L cooling system capacity is just short of 3 gallons and I was able to get 2 gallons of fresh 50/50 antifreeze into the system (1.5+ in the radiator and the remainder in the drained and rinsed out overflow) so I'm happy with the results.

Attached is a scan of the diagram of the plugs location. Does anyone have an actual image?

[Okay, can't upload an image from my desktop for some reason. Sorry.]

https://cimg8.ibsrv.net/gimg/www.che...f83fdefb34.jpg

My coolant temp sensor is on the thermostat housing, what ones have it in the block?