I've tried in full sun and total darkness, and everything in between, and
there's just no way to see what the coolant level is in the reservoir bottle
without taking out the battery, and maybe not even then. I don't know how
they check it at the dealers.
Anyway, I thought it might work to use the rubber hose that goes down into
the bottle as a dipstick. If the hose extended three inches into the coolant
when the engine is cold, does that sound like a reasonable fill level? As
the engine heats up, the level would rise, and the only danger is that it
would end up too high. (Although I don't see that that would actually hurt
And three inches would allow for a fair amount of time between checks without
the hose ever being out of the coolant.
What do you think? Three inches? More? Less? I don't suppose there's an
official coolant dipstick designed for this car. Nah.