Sorry, dude. Great car, flawed engine. Fix the engine and then the engine is great too. BTW, 1500/miles per quart is not good. My 87 with 250kmi (and also an OM603 engine, like yours but 3.0L) gets about 7500/quart, and my other one (now wrecked) was in the 4000-4500/quart range (due to a leaky turbo, IMO). But a quart every 1500 miles, well, that's not a good sign...
