A frustrated friend of mine just asked me for advice about his car... a '95 Lumina. The car is in the shop for a coolant leak near the front of the engine (bad enough that he cannot drive it). The mechanic is saying that he used the wrong anti-freeze/coolant and this caused his leak. He said he should have used "Gold Seal" coolant instead of the regular "green" stuff ... the mechanic wants $500 to fix his car. I may be wrong, but this just doesnt sound right to me. Anyone ever heard of this?