I have a 1989 toyota 4-runner, 6cyl. 3.0 liter w/about 160,000miles. I have replaced the thermastat twice and the raditor keeps sucking the fluid somewhere in the engine and i'm seeing alot of white smoke coming out of my exhast. It is still overheating and I am wondering if my problem are my head gaskets bad? It has taken the rest of my money for this month to try to get my problem fixed. Any kind of help or advice you could offer would be greatly appreated.