'01 V70 Coolant Debacle

cham · Post by **cham** » 06 Mar 2025, 17:04

Just an update; got through with the flush a few days ago. Ended up using 6 gallons of distilled water just to be sure the old coolant was almost non-existent. FDP Euro claims my N/A 2.4L V70 has a coolant capacity of 8L. When draining the radiator I was getting only about 4L of coolant out. Naturally I added a an entire gallon (3.8L) of concentrate as theoretically there should still be 4L of only water still in the block. This should work out to be about a 50/50 mix.

Got a cheap Peak Coolant tester and the results showed a maxed out freeze and boiling point. Unfortunately does not give ratio but clearly a large bias towards glycol. Surprised considering the calculations work out to actually give a slight bias towards water. Anyways, I'll be draining some out and adding water to get it closer to that 50/50 ideal ratio.

Post by **matthew1** » 06 Mar 2025, 17:53

Welcome to MVS, cham.

IIRC, the concentrate:water doesn't scale linearly in freeze protection. It's an irregular curve. Meaning 100% concentrate has worse protection than proper mix.

Post by **Blacklab467** » 06 Mar 2025, 18:58

matthew1 wrote: 06 Mar 2025, 17:53 Welcome to MVS, cham.

IIRC, the concentrate:water doesn't scale linearly in freeze protection. It's an irregular curve. Meaning 100% concentrate has worse protection than proper mix.

Good point Matthew, also the coolant doesn't hold as many BTU's as the water so is less efficient at removing heat.

Post by **abscate** » 06 Mar 2025, 23:41

Welcome to the magic of boiling point elevation. There are not meaningful differences in thermal capacity between water and coolant and mix, but the boiling point elevation is near optimal at 50-50.

That being said, in temperate VA you dont have to worry about this, extreme temperatures are desert and top of Canada, not really anywhere in the lower 48 except maybe in the SW.

cham · Post by **cham** » 07 Mar 2025, 10:06

Very good points guys, since water alone has a higher specific heat capacity, heat transfer is improved across the fluid compared to a mix in my experience. When I was running just distilled water during the flush, getting the engine up to the thermostat opening temp was more difficult then when compared to my current mix.