temp? problem Please help!!!!!

in Oldsmobile
I have a '91 Silhouette that recently has started to stall out at the first stop getting off the freeway or when it gets hot. I've tried 2 separate mechanics and both tell me there is no problem they can diagnose. Anyone have a similar problem???? I have to fix or sell it and can't afford to pay yet another mechanic to tell me there's nothing wrong.
0
Comments
Some mechanics will tell you to convert to the green coolant after a flush. Some will say it's the gasket design. I think the DexCool is a more sensitive coolant if you have a leak since it thickens and sludges with the air. Thus the need to flush once you see a leak. On your car, the real question is what's leaking. The intake manifold gaskets are known to be issues on this and other GM vans. The last one I replaced, the mechanic said GM tried to fix the issue by putting in a more durable gasket, so that's good, but he also gave me a life expectancy and he felt the intake gasket failed because of where the one bolt hole was placed and how much plastic encasement was left to hold the O-ring. Once the plastic holder became soft, the o-ring doesn't seal as he put it. GM as he suggested has tried to redesign the palstic part, and I think he mentioned they went to a metal sheath to reinforce the plastic, but he still didn't think it solved the bolt hole placement. In any event, I have no idea if what he was saying is factual of not. While he didn't think the DexCool itself was the issue, my opinion says the DexCool needs to be watch more carefully thyan the green coolant if it gets low. The DexCool is an OAT or organic acid technology, which is said to be a better corrosion inhibitor, but that is if it's wetting the metal parts on your coolant system. If it isn't, I've read that it isn't as good as the green since the green forms a silicate film on the metal, which will still provide corrosion inhibition if not wetted. But the down side is the silicate film isn't as ggod a heat conductor, so the system can run a little hotter just from that, plus I think the DexCool has better thermal conductivity in the coolant itself. Some people really like the green, some say stick with the DexCool since it's tough to guarantee all the DexCool is flushed out even after a flush. The Dex and the green coolants are not compatable. On my first van, when it had the intake manifold gasket replaced, they actually recommended in flush and convert it. You should get of course an oil change, and my trusted mechanic thought it'd take about 3 oil changes to get the water out of the oil system if the two mixed. Anyway, good luck with it, hopefully there wasn't more sludging in other parts which could cause corrosion.
But all the temp problems, for me, always go back to the head gasket. Been replaced twice. :lemon:
For the record, I got my settlement check yesterday! Yay!