I'm about to do the same type of service. I'll be watching this thread with great interest.

 

Drain and refill, idle for 20 minutes and topped off. After 5 days of commuting 75 miles a day it dropped below the max (but above the minimum). and got one more top off. It is a 2.5 4 cyl BTW.

 

i did let it idle for till bubbles stopped for a while (both spontaneous and manually burping) but didn’t time it. I used one of the nifty no spill coolant funnels which worked great. Maybe it didn’t idle long enough so I’ll probably let it idle some more with the funnel on and see what happens.

This is kindof a 'trick' question.... the number of 'heat cycles' before level in reservoir settles out (cold engine!) really depends on how much air you were able to purge out when the system was refilled.

I always pull the upper radiator hose off the radiator and FILL THE ENGINE (thru the hose) before putting the hose back on. Even when filling like this, it may take several weeks heatcycles before the reservoir settles out (cold engine!)

That makes sense it only equalizes on a cold engine. And the couple days my outback sat without driving I had the biggest drops.

I did read something like the reservoir gets closed off during engine operation unless the engine over heats or needs to dump some coolant out. Then as the engine cools down, it sucks up coolant when reservoir access opens back up. I’ll be the first to say I’m mechanically retarded and google/YouTube everything 🤷‍♂️

Not unusual at all. On just about every vehicle I have replaced the coolant in, multiple drive cycles have been required to finally get the system topped up properly. I check the cold level first thing each morning and add coolant as required. By the third or fourth morning, the coolant level finally remains where it should be for normal operation.

I’ve only don’t coolant on my previous vehicle which is a civic that I’ve had for 10 years and that was an easy 1&done. In fact the outback’s coolant level dropping made me go check my civics coolant level bc I have never check it after it’s flush/drain/fill a couple years ago 😅. The civic came back normal haha. My civic is super easy and I’ll be bummed/sad when I sell it after getting the outback in order

 

This is kindof a 'trick' question.... the number of 'heat cycles' before level in reservoir settles out (cold engine!) really depends on how much air you were able to purge out when the system was refilled.

I always pull the upper radiator hose off the radiator and FILL THE ENGINE (thru the hose) before putting the hose back on. Even when filling like this, it may take several weeks heatcycles before the reservoir settles out (cold engine!)

 

Not unusual at all. On just about every vehicle I have replaced the coolant in, multiple drive cycles have been required to finally get the system topped up properly. I check the cold level first thing each morning and add coolant as required. By the third or fourth morning, the coolant level finally remains where it should be for normal operation.

 

Yep, I have to add a couple ounces of my "Asian Blue" coolant perhaps once per year, usually during the summer. I am certain it is due to nothing but normal evaporation.

 

3 drive cycles after drain and fill after replacing the coolant pipes that feed oil cooler

 

I would say I needed to add a bit to the reservoir a couple of times until the level stayed consistent. And this was after spending quite a bit of time letting the bubbles out using a no spill funnel. Obviously, the reservoir level will probably drop a bit over time.

 

I should update to say right after I posted there was one more drop and now it seems to be settled out. So I think we are good!