Water Consumption

pkastagehand

I have a 2002 Malibu with the v6 with AL heads and cast iron block. I bought it with about 112,000 miles on it. Shortly after discovered oil in water. Mechanic said it needed intake manifold gaskets; factory gaskets fail around 90,000 to 100,000 miles. OK, got that fixed. A few weeks to a month or so later, start losing water. Never a drop under it while sitting after driving unless it got low and it trapped air and started gurgling and steaming out the overflow. Mechanic tests it and says combustion gases present in the cooling system. Diagnosis: heads warped. OK, so at great expense I had him tear down and regrind, etc. That was late August. Ran fine all winter. This month drove from MI to PA (600 miles) no problem. Left central PA to drive to Baltimore and got a low water warning. Put some water in and drove back to central PA the next day and again got the low water warning. Worrying now that I either need to unload this car or pay to have heads replaced or whatever it needs at GREAT expense. Car maybe not worth it, especially if it is just going to warp the heads a third time (if that is what is going on).

So on Friday, the day after getting back in central PA from Balt. MD, I drove to north west VT. I drove around a fair amount in the Montpelier/Stowe area all weekend and on Monday back to PA, no problem. (Over 400 miles one way).

Before driving back to MI I checked the water and it seemed a bit low but not much. (Car was cold where before I was checking it hot often, so maybe that is the difference.) I drove from PA back to MI this past Sunday. Again No problem.

So, here is the question. Why would it use water that one time and then be back to normal? And following on that, am I likely looking at a huge rebuild/new heads, etc. or was it possibly something else like maybe not having the cap on the tank tight?

I'd rather not have to buy another car right now but also don't want to keep putting a ton of money in something this old. All advice welcome.