How to determine the cause of leak in a Mazdaspeed 3?

Question

When stopping for gas on the way home, I noticed a red fluid running out from the front of my car. It had a reddish tint to it and was coming out from under the passenger side wheel. I checked the anti-freeze resevoir while at the gas station and it was completely full.

I drove my car home (less then a mile), and left it running while I got out and looked under the car; there was no drip. However after idling for a few minutes it had a steady drip of fluid.

Checking the resevoir again, it was still at the fill line.

Is it a anti-freeze leak, or could it be something else? How do I determine the origin?

EDIT

It's definitely an anti-freeze leak, I just went out and checked and the resevoir was entirely empty.

So 2 questions: 1. What could cause that? 2. Can I fill it and drive it to a mechanic in the morning and be ok?

Answer 1

As long as the engine hasn't overheated, you should be fine. If it has, you may be looking at an expensive repair bill...

There are two likely sources of a coolant leak - a burst hose or a leaking radiator. Open the bonnet and check any hoses you can see for either signs of damage, or signs of the leaking fluid - Red OAT often leaves a slight orangey deposit as it evaporates, so you may be able to spot where it has leaked from, or follow the trail of fluid back. Bear in mind that a small leak in a damaged hose may not be obvious to look at, so you might bnot be able to spot it easily - and it doesn't need to be a big leak to lose a lot of coolant. Radiator damage is harder to spot, but again the tell-tale deposits may give you an idea (assuming you can see the rad of course, and it isn't hidden behind loads of other stuff)

Whatever you do, don't try and run the engine with no coolant in it, as it will overheat very quickly! If it has lost that much coolant in that short a distance, I would not recommend driving it anywhere until the leak is fixed, although for a smaller leak I'd refill with water and bleed the system, drive it to a close place of repair and then flush it through and refill with the correct coolant mix.