I just bought a Rover with a 300TDI. I get it home and am looking underneath and see a threaded hole under the flywheel. Looks like there's supposed to be a plug there. I ordered one, but my question is what's the plug for? Oil doesn't come out there, and neither does transmission fluid. What is it meant to drain? And what fluid have I lost if there's no plug there?

 

It sounds like the drain off hole for the Bell housing ,,and there is/should be absolutely no oily fluids or grease in the flywheel area , some water if any , so don't worry .. , if you off road or go wading put the bolt you ordered in it .. ( before )

because that's the transfer point of the drive from the engine to the gearbox and transfer case to the wheels ...

 

That makes sense. Do you know why there is a drain hole there at all?

 

its really for water mostly , because LR's were designed to go just about anywhere , and so does water...... so it makes it easier to drain off ,after wading in a river or so...

 

An old series owner trick is to remove the plug storage bracket from the bell housing (yes, Series Rovers had a storage bracket for the plug) and bolt it to your dash. That way there was never any question in your mind if you had the wading plug (official name) installed.
The bracket was just an 'L' shaped piece of flat stock drilled and tapped to accept the plug.

 

Wading Plug! Brilliant. Thanks for that. I guess question is why would ever not want it in? Does the engine run better when air can get in?

 

Found this on another forum: "However, clutch slave cylinder can leak into the bell housing, also, gearbox and engine oil seals can leak into the bell housing.

I believe the hole at the bottom is there to allow these fluids to escape, and indicate that something might be amiss, so wading plug out for normal operations, back in when wading."

 

That's pretty much it.