I'M stuck??? Sniper elite V2

I have blown up the bridge, that the Russians were crossing, now it wants me to destroy a tank and the only thing I have is the gernades to throw at it from across the moot. How do I destroy a tank with only gernades from that point?? Have been trying to figure it out now for 3 weeks. Other than hints about hitting the fuel tank, I see no fuel lines from where I am. HELP??