This question is for a guy at work with a 2005 pontiac Aztek mini van.He changed his oil but can not figure out how to reset the oil change reminder light and he says it is not in the book. I told him there is a way with turning on the key and stepping on the gas a few times. Anyone know how to reset it?

1995 Olds Achieva 3.1L V6, 110,000 miles. Original symptoms are that there was no heat and the temp gauge was going into the red. On popping the hood, I noticed coolant leaking past the cap. Had the thermostat replaced. Now have heat, but the temp gauge is swinging a lot - will creep into the red, then drop back to about the middle of the gauge. I can smell coolant when I started the car and stepped out of it and then again when I shut it off and got out, but not when inside the car. Popped the hood and saw that there appears to be coolant leaking from the cap again. Questions: 1 Should I get a new cap? 2 Is the new thermostat not performing correctly? 3 Is there something else wrong that I'm missing? There does not appear to be any coolant leaking from the water pump. I bled the system and think the air is out.