Radiator Overflow Cap Left Open

[Inv4drZm]

I just noticed the radiator fluid reservoir (more of an overflow right?) cap was just sitting on top of the container, and not latched down. Now I can barely see any fluid in the container (below 'low' level). I haven't noticed the gauges running hot or anything (yet).

I'm due for an oil change, so I could take it in next week (installs full suspension system in one weekend, but too lazy to change oil).

Or should I just go buy a quart or two of coolant and fill it myself; would it be alright to mix with what's in there already, or should I flush it out from the cap letting in who knows what?

I kindly refer to your good advice. (AKA I'm a noob at vehicle maintenance) Thanks!

 

[BlackWorksInc]

If you're going in next week, just mention to them to check the fluid level. Was the hose for the reservoir in the bottle at least?

 

[Inv4drZm]

Yeah, the hose was still inside. Unless that stuff evaporated, it was probably low to begin with as I don't see any splash marks on the top. Must be one of those amazing Toyota engineering feats; the cap pops off telling you the coolant is low...

 

[Slowgoat]

Xerex Asian or Genuine Toyota SLLC (Super long life coolant)

Anything else and you could run the risk of damaging the system.

http://www.amazon.com/Zerex-675130-Vehicle-Anitfreeze-Coolant/dp/B0033QO022

Amazon.com: Toyota Genuine Fluid 00272-SLLC2 Long Life Coolant - 1 Gallon: Automotive