Low Coolant - Top it up or flush and replace all?

[smokey7722]

So I've had my truck garaged for 2 months or so now and I decided last weekend to start looking it over for any maintenance items. I noticed that the coolant was below the low line (about an inch or so) and so I bought a gallon of coolant (Toyota stuff) to top it up.

The question I have... Should I top it up and if so, do I go right up to the H line or do I go in between the L and H lines? Or should I flush it and get another gallon? I'm pretty sure the coolant was flushed when I did my timing belt @ 90,000 miles and I'm now at about 125K however I also now live in Vegas so its a LOT hotter. 35K really isn't old for the Long Life stuff but do I want to mix old and new?

 

[fourwd1]

First just see how it looks. If it looks dirty, cloudy, weak, etc it may be time for a flush.
Since coolant is the most important thing after engine oil, you really can't go wrong by changing it.

 

[Acidmeld]

You'd be good to do a drain and refill. Coolant will steam off over time naturally. Especially in a climate as dry as Vegas.

 

[KB084RUNNER]

I would just top it off.

 

[SUBTEGRAL]

Drain it, fill it, then watch the level.

 

[cobhobaroblobie]

If it's brown, flush it down

If it's neon green, top it off.