temp fluctuating again...

I have a 99 Venture 3.4L..not long after getting the van it started overheating, with the temp going up & down randomly. Eventually, the temp would not go down & it was undrivable. I inevitably had to have the engine "rebuilt" due to seriously blown head gaskets. After getting it back, it drove like a champ for quite sometime, then I noticed a coolant smell again along with the dreaded low coolant light. When getting my tires changed, the mechanics noticed a leaking hose & changed it. The smell went away, but the low coolant light did not....it started coming on as soon as the temp would go up...then go off when the temp went down.
I took the van back to where it was "rebuilt" and they told me the temps going up & down was a water pump issue. So, we bought the parts..changed the water pump. Not fixed. It has started overheating again more frequently. I added Bars Leak on a whim, following a suggestion that it could be a small pinhole leak somewhere that was letting pressure out. This actually stopped the overheating for about 2 weeks. Now I am back to the same. Running hot...heat goes cold...have to pull over. Start again & the gauge will suddenly go down...heat will come back on. We have also bled the line to try & release any air...this fixes it for a short while only.

This is the SAME issue I had BEFORE rebuilding my engine!!!!! What did they NOT FIX when I brought it in?? Any suggestions? I do NOT want to bring it back in & have them scam me..I already gave them enough money!
I'm so sick of this overheating issue that has plagued me since I bought this thing...used..and now I have 2 payments left! UGH.

Real bad luck....once is "normal" for this engine, but twice is too much...you have all reasons to fulminate....
My brother had his head gaskets (a 2002) done a few months ago: mechanics told that with new type gaskets, NEW head bolts, planing the heads , and all the rest coming with it, it was better than new.....
That is really annoying, but is there some kind of warranty you are entitled to...but there is no way to escape, it must be done again....

the new itake gaskets that gm came out with are the same gaskets as before fluctuating temp could be that you have air still in the system there are two bleeders on the system one above the waterpump one on the thermastat housing try bleeding till you get antifreeze to come out don't turn all the way out jut enough to bleed. but i bet the intake have blown . i have put one set of head gaskets and two sets of intake gaskets in two years. the intake gaskets are made of plastic some kind of rubberized silicone and a ***** to put in. if gm had to recall all of the 3.4 they have sold then we wouldn't have to worry about gm anymore.