2008 Toyota Tundra with a 5.7L V engine
I noticed last month that my coolant reservoir was well below the 'low' mark. I filled her up, only to find out last week that it was back to the same spot (about an inch above dead empty). What could be causing this behavior?
An internal leak would completely use the remaining coolant, then, when depleted, overheat my engine. But an external leak (a crack in the reservoir itself) would be obvious, and I would've noticed a huge puddle under the truck the next day.
I had the dealership replace a bad water pump two months ago, at about 80k miles, so that could have something to do with it. Before going back though, I'd like to at least diagnose and understand the issue. Any thoughts?