Coolant drain and fill question (more out than in?) Topic is solved

[cantabrian]

While doing my PCV system, I drained coolant from the lower radiator hose. Probably 5 quarts came out. While filling it back up, only about 4 quarts went into the reservoir tank. (I started the car and let it run, but the level didn't fall.) Is this normal? Is the problem simply that the coolant won't really start flowing through all the hoses until I'm driving? Just checking. Seems weird.

[cantabrian]

Well, answered my own question. I took some extra coolant mix when I headed out. When I left, it was at the max line. About 15 minutes later, the "coolant low" indication came on. The reservoir was almost empty. Filled it back up to the max. And then another 15 minutes later, checked again, and it had settled close to the min line. I guess it just took a while to get into all the fins of the radiator and to circulate through the system. Sorry for asking a dumb question!

[vtl]

Fully drained system (when the block is dry also) may be hiding trapped air for couple of days.

[cantabrian]

Thanks, vtl. One more coolant question: in my haste to drain enough coolant to do the PCV system this weekend, I drained from lower radiator hose and got out about 5-6 quarts. I drained out some sort of dark green coolant (I bought the car used). I put blue volvo coolant in (mixed 50/50).

My problem: I didn't read about the plug on the back of the engine block till I was almost done, and it was dark out. So I was lazy and didn't get everything out (I guess about 2.5 quarts are back there?). I thought it would be fine. But I just learned now about the potential problems from mixing OAT and HOAT coolants (sludge/plastic). I don't know what kind of coolant was in there before.

My questions: should I worry about this mixture (5-6 quarts HOAT, probably 2.5 OAT or whatever else)? If so, how soon should I drain and fill? That is, TODAY? Or is it ok to leave for a week or so? I don't want to ruin my cooling system! How hard is it to access that plug on the back of the engine block? It seemed kind of high up and potentially messy, though I suppose I could catch it in a funnel.

I imagine that this mixture happens all the time in cars serviced at various places. So, would I be overreacting to drain and fill again?

[vtl]

OE coolant gets darker greenish with years, it could be that you've drained original coolant.

[cantabrian]

Interesting. So, you suggest not worrying about it for now?

Perhaps the path of least resistance (or, at least, easiest to do int he driveway after work), is to drain it again from the radiator, and refill. I don't know the math on it, but I imagine that would dilute the previous coolant down pretty well.

[vtl]

If you worry so much, get a sample from cooling system and send it for analysis. Or, better, the old coolant which you drained.