cardudeusa:
If the exhaust gas is white in color and smells sweet then coolant is getting burned in the engine. If you notice the exhaust more in the cold weather then it is just condensation (lucky for you). You can do a compression check on the engine and you can check the oil for cream-colored foam/scum (coolant mixed with oil). If you rev the engine in the driveway, you might see bubbles coming out of the expansion tank.
My money is on the intake failing after getting a little overly warm. Do you smell coolant just after the car is parked (after driving around for a while)? Is there any staining in the valley under the intake? Take a good look at the thermostat area for a very fine line (i.e.--hair-wide) of coolant around the thermostat. That is a common area for the leak to start to show up.
Some things that could cause the coolant/degas bottle light to come on would
1. improper water to coolant mixture.
2. pockets of air trapped in the actual coolant system.
O.p. get yourself a black light pen, and at night start your car in a dark area and start looking for bright green areas.
From cleaning my cooling system, sometimes very tedious to get all of the air pockets out, sometimes causeing the water pump to squeal.
The water in those 50/50 mixtures do evaporate, so replace w/ water.
The head gaskest in the mod engine are stout, if you did not over heat the engine to the point it stopped, chances are its not the head gasket.
My '95 honda civic blew a head gasket, there were no warning signs, just saw a ton of white steam out of the back of the car and it would not start again until the head and thermastat was replaced.
