Mitsubishi Repair: Diamante, coolant level, radiator cap

Question
I have a 1998 Diamante . I have terrible coolant fumes inside the car. I thought it may be th eheater core. Although, the core is not leaking anywhere. A local repair shop told me the heater core is not leaking. what else can be causing the fumes?

Answer
Terry,
You're right, the most obvious cause would be from the heater core.  But if you cannot find any leaks, than it must not be that.  Another possibility is that you have too much coolant in your system, so when you car warms up, a lot of coolant goes into the overflow tank.  The cap on your overflow tank might be loose and leaking excessive vapors from it.  When you have your vents set to "fresh air" and your fan on, you can be sucking in those fumes from the engine bay.  Coolant may be dripping on some thing hot in the engine bay, which would amplify the smell.

The best thing to do is keep an eye on your coolant level.  When you engine is cold, you can twist off your radiator cap.  The coolant should be just below the cap.  NEVER remove the cap when your engine is hot or very warm.  If you notice that the level continuously goes down, that means you're leaking coolant somewhere.  You'd probably need a mechanic find out exactly where that's leaking, if that's the case.
Good luck!