I just had a race with the Group A BMW. After fuel calculations, I needed ~37L of fuel for a race. I put in 42L as I don't like being the guy who died on the penultimate lap. Aaaaanyway, fast forward to lap 3 of the race, crew chief tells me I need to come in for fuel before race end I look down at my fuel gauge, seeing I am already down to 14L with. I continue on expecting to be down to 4L by lap 4, but no, it hangs at 12.5. Next lap is 10.2. The question lies in the title, are fuel leaks a mech fail?
You may have just added fuel in quali, didn't save the setup and it reset back to the qualifying fuel for the race.
Great idea I think oil leak is already a part of mech fail, isn't it? Or an air leak, the engine is getting false air and therefore a loss of power....misfires, damaged generator, damaged fuel pump,.... I can write books what I experienced with my MB190e (W201). But everything was repairable, except the hole(s) in the cunstruction of the car --- bad rust, killed the car with just 28 years...
Rust failure might be a bit too long term for most sim drivers. A 24 years of Spa race is difficult to fit in with other things in your life.