1998 Pontiac Bonneville coolant

[quote:9a8d0db630="lisa achenbach"]Steering problem
1998 Pontiac Bonneville V8 Front Wheel Drive Automatic 160000 miles
----------------------------------------------------------------
coolant low light came on;added coolant, engine running funny, had to go 80 miles and filled reservoir 2x. overheating. got home and empty again. heater not working.[/quote:9a8d0db630]

If you pull sparkplugs do you find antifreeze. I had this problem. took it to a garage and it was hydro-lock and they fixed it for me for about $500. I also have a 1998 Pontiac Bonniville 3800 6 cyl with about 155000 mi.

The 3.8 motors are notoriorious for intake manifold problems. Don't fool around with this as I have seen them allow enough coolant to get into the cylinders and cause a hydrolic lock up.

The manifold self-destructs on the top passenger side of the manifold where the poor engineering made for a pressure point for coolant to erode the plastic.

That would be my first suspicion.
If you pressure test the cooling system and see no external leaks, be sure to pull the plugs and spin the motor over to be sure there is no coolant in the cylinders. Look at the plugs carefully for abnormal conditions.