They should have mentioned it. It could be just seeping slowly. A friend's radiator was leaking in the lower part due to rust. The fluid level was not changing very much, but you could see that the radiator was always wet on the bottom and had some pinkish coolant residue forming there.
The radiator is not difficult to change. On a manual transmission car at least. AT is bit more work since it has the trans fluid cooler in the radiator as well.

 

might have to get searching for an aftermarket one soon then? I wouldn't want to overheat on my way to or from work.

Hopefully it doesn't get too bad over next couple weeks as I need to save up some cash!

 

Just monitor the fluid level and your temp gauge. If it behaves weirdly in any way, like 2 notches above or below where it usually sits (the middle). Stop and check the fluid, with the usual precautions, like don't open the radiator while hot, etc.
Carry some fluid with you to add as necessary.
Basically the only danger would be that the leaking spot bursts into a big leak and you start losing coolant real fast. Then your temp gauge may actually drop since the sensor would no longer be submerged in coolant. That is the extreme case.
How long is your commute?

 

It takes me 40 Minutes One way to get to work, will keep an eye on it for now for certain

 

In that case you should not be able to lose a dangerous amount of coolant on one trip, unless it bursts of course.

 

I'm with ganda1f. Your long commute could be disasterous one morning or afternoon. Make sure its not a bad hose or loose clamp either.

-SP

 

I would get to the bottom of this sooner than later. My corolla only had 150k miles on it and the radiator was meticulously maintained. I only happened to figure out my radiator was leaking when I saw some steam in the headlights one night when the car was idling. I opened the hood and there were several small pinhole leaks in the radiator spritzing out fluid. Had I not noticed this one night, it could have been disasterous. I put in a new OEM radiator and hoses. (You can search for my thread if you want to see more details of the job and some OEM choices).

 

If the leak is small (a couple pinholes) or otherwise contained (a crack in a relatively flat spot) then you can patch it with some repair epoxy. A tube costs about $5.99 at the auto parts store. They make repair epoxies for plastic and metal on radiators, and both are meant for this application.

It's really easy to do. First, clean the area with 100% mineral spirits in a microfiber cloth, then take some 400-grit sandpaper and scuff the surface a little. This will give the epoxy a nice rough surface to grab onto. Then clean the area again with mineral spirits, wipe it down with a dry microfiber cloth, and let it dry for a few hours in sunlight.

After it's dry, pull out your repair epoxy and mix it up according to the instructions on the tube. Then just apply it liberally over the leak; make sure you use a good bit. Try to sculpt it like a proper patch so that it covers a wide area in and around the leak. After you've got it pretty much sculpted the way you want, take the palm of your hand and beat on it a bunch to flatten it. This will push it against the area and make it grab tighter and seal better.

After you're done with the repair leave it alone for about an hour to set up. After an hour, pop the hood, crank up the car, and have someone rev the engine while you check the patch. If it's not leaking when the engine is at high RPM that means you're good to go. The repair epoxy will be fully hardened after 24 hours. If it IS leaking after an hour, sand down the specific area it's leaking from on the patch and add a little more epoxy to that area, or just chisel the patch off with a flathead screwdriver and try again.

This takes an afternoon and about 20 minutes of actual work and it only costs $6 to try, compared to buying a new radiator at ~$80 and spending a couple hours of actual work swapping them. And if the patch just won't hold, you can always buy a new radiator and you're only out $6.