March 2012 - changed coolant (mileage not recorded, but no more than 64,500mi)

Sorry I wasn't more clear... Actually, this is how I initially read your post. Apparently, I over-thought it trying to understand where the "trapped air" that JDS60R mentioned would be and how running the heater would clear it or could otherwise affect the flow of coolant through the heat...

never mind: I think I found a hint in a previous post "mix flaps in the heater box" here's my guess: the heater core can either have hot coolant coming directly from engine or cool coolant from the radiator - the mix flaps control the ratio of hot-to-cool coolant - so if I don't turn on th...

Yes - The heater core is always open. Thanks - this place and you folks are the bomb. Turn on the heat now to assure you do not have any type of trapped air. I will definitely do this, but for my edification: if the core is always open, how would running the heater do anything other that just blow ...

FjordMoCo wrote:I believe the heater core is permanently open to coolant flow...

That would be a relief.

Can anyone confirm, or express more certainty, that this is the case?

Thanks

I just realized something I failed to do: I never turned on the heater during this process. I'm freaking sick to my stomach. Obviously, I'm going to have to repeat some of this process. If I know how much the core holds, I can probably calculate how many drain/fill cycles I need to do. Anyone have a...

For anyone stumbling upon this prior to changing his/her coolant, here's the block petcock: Here's the radiator petcock highlighted But, that thing is flimsy - you want drain by detaching the lower radiator hose:

With the helpful info from the folks here and a little bit more contemplation, I finally got back to this on Sunday and thought I'd share my experience: After finding the block petcock valve, I realized that simply opening the valve would make a monumental mess. But I also noticed that the valve was...

I haven't drained it yet (wasted all my daylight trying to figure out what I was doing) - and I want to wait to see how the conversation goes with the insurance co. On my monitor, it's a pretty accurate representation of the color - an opaque, Orange Crush/Orange Nehi color. I'm hoping "rust in...

Here's a pic of the coolant that is currently in my car.

Before I have this conversation with my insurance company, can someone confirm that Volvo has never used an orange coolant?