Oil Drain Plug torques petrol & diesel different ?
 

Why is the recommended torque for the diesel drain plug double that of the petrol ?
54Nm (40ft-lbs) (seems a little excessive) to 20 ft-lbs on petrol

Could be down to a different sized thread, or different materials being used. Or it could just be the wrong info has got into the owners/service manuals (wouldn't be the first time).

I don't know anybody who torques sump plugs anyway. I just tighten the plug on my TJ as much as I think it needs. Tight is tight.

Diesels are a higher compression engine so internal pressures are higher.

So will the sump for the diesel be more robustly made compared to petrol ?

Yes it will be as diesel engines are built stronger to cope with the pressures.

That sort of makes sense, but the sump shouldn't be pressurised... It has breathers that connect to the rocker covers & the PCV to suck the fumes out & feed the vapours into the inlet of the turbo.

So while the material of the sump might be stronger, the sump & sump plug are not structural parts, so why would it need to be tighter in the diesel?

It’s simply because the engines are made by different manufacturers.