How about this:
1/ No health on tanks
2/ Below a set point, as is now, the tank begins to smoke - At this point, if not further damaged soon after, the tank will 'repair itself' to full health.
3/ Below that, it begins sparking and this is equivalent of a bleed in humans (ie. health begins to fall)- Passengers either need to bail or get out and repair it (AHEM or use the hatch and repair it) - Screen begins flashing red or something from the crew in the tank so they know how bad it is , besides the sparks seen from outside
4/ As it falls further in health, it begins to burn as currently exists (on the engine plate) - but by this point, it will be too late to reapair as it will be repaired slower than it self-destructs, even with you in it (It takes a while to blow up, but it has to be abondoned no two ways - So after really bad battles, youl would have tanks lying across the battlefield, not blow out yet, but abondoned for good reasons - And more so since you cant tell how long you have till cookout)
5/ Shermans etc, basically smaller tanks, will thus have a chance to keep their crews among the living while being rendered unusable (For all intents and purposes) and yet, remain not completely blown up at one hit from an 88 tank or cannon shell
*You get to know how badly your tank is hit from the 'bleed effect', the fricking cannon that hit you should be a clear sign too
And we get a more real-to-life representation of tank combat and tank damage