412matt Posted September 21, 2020 Share Posted September 21, 2020 So my 09 legacy 2.5 currently has green coolant in it, not sure if it’s subaru coolant or not. I planned on changing it so today I bought blue subaru long life coolant to put in it. I also planned on running distilled water through it to get most of the old stuff out. How could I do this to get most of the old coolant out? Also, should I use the subaru coolant conditioner? I didn’t buy it because I think it’s a scam. My head gaskets seem to be leaking a little bit and from what I’ve read adding the conditioner won’t help if they already started leaking. Thanks in advance Link to comment Share on other sites More sharing options...
apexi Posted September 22, 2020 Share Posted September 22, 2020 (edited) I looked into this since no one has replied yet. Seems like pulling off the thermostat housing is the best way to drain the engine block. In the attached image, step 4 is just draining the coolant from the radiator, it doesn't say anything else. Spill free funnel is also handy to have for burping the system https://www.amazon.com/Lisle-24680-Spill-Free-Funnel/dp/B00A6AS6LY Also, I don't use coolant conditioner, I don't think our 09's need it. Our cars leak oil from the head gaskets, never heard of them failing and leaking coolant. Edit: After thinking about it a little more, I wonder if this is why subaru calls for shorter coolant change intervals after the first one, because they don't expect you to get all the old coolant out by draining the radiator. Edited September 22, 2020 by apexi Link to comment Share on other sites More sharing options...
412matt Posted September 22, 2020 Author Share Posted September 22, 2020 I looked into this since no one has replied yet. Seems like pulling off the thermostat housing is the best way to drain the engine block. In the attached image, step 4 is just draining the coolant from the radiator, it doesn't say anything else. Spill free funnel is also handy to have for burping the system https://www.amazon.com/Lisle-24680-Spill-Free-Funnel/dp/B00A6AS6LY Also, I don't use coolant conditioner, I don't think our 09's need it. Our cars leak oil from the head gaskets, never heard of them failing and leaking coolant. Edit: After thinking about it a little more, I wonder if this is why subaru calls for shorter coolant change intervals after the first one, because they don't expect you to get all the old coolant out by draining the radiator. If I didn’t pull off the thermostat do you think it would be fine because I have green coolant in it now and I’m putting in blue coolant? I don’t think it would be enough to make a difference but I have heard of people saying that green and blue coolant can’t be mixed. Link to comment Share on other sites More sharing options...
jaylew Posted September 22, 2020 Share Posted September 22, 2020 (edited) I am not sure if blue and green can be mixed. I use the peak long life (cheap at HF, and actually really good). Coolant should be changed on a time interval primarily rather than mileage (it is all about how the coolant's additives that prevent corrosion wear off) If you are doing a flush and don't wish to remove the T-Stat (which is the easiest way, though get a new gasket for that), then the solution is dilution. Run the car a few cycles of straight water (di water from the store, not tap water). 1) drain old coolant at radiator + T-Stat hose 2)fill up with DI water 3) run the car for a little (like 10-20 min) to dilute the old coolant 4) repeat 1 through 3 a couple times until draining is nothing but water 5) final refill with new coolant You can be fancy and add coolant flush half way through the water cycles I also second the spill free funnel, super handy Edited September 22, 2020 by jaylew Wagon is LIFE! - 265,000 miles and climbing Unofficial Build (Restoration) Thread Steering Rack Rebuild Link to comment Share on other sites More sharing options...
59ctd Posted September 23, 2020 Share Posted September 23, 2020 The green and the blue coolant should not be mixed as they are different chemistries and are incompatible. As mentioned a flush after draining as much green out as possible with distilled water is probably enough to get almost all of the green coolant out. Keep in mind that once you drain the distilled water solution there will still be an amount of water in there and if you use a 50/50 pre-mixed blue P-HOAT coolant the end result will be a higher freeze temp due to the water that was still in there. IMO, the color of the P-HOAT fluid does not matter at all. Whatever wally mart has on sale is what I use. Link to comment Share on other sites More sharing options...
Max Capacity Posted September 23, 2020 Share Posted September 23, 2020 FWIW, since 2007 my wagon has been on Prestone or Peak Global coolant. I change them out when the timing belt is replaced. You don't need anything more. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
412matt Posted September 24, 2020 Author Share Posted September 24, 2020 The green and the blue coolant should not be mixed as they are different chemistries and are incompatible. As mentioned a flush after draining as much green out as possible with distilled water is probably enough to get almost all of the green coolant out. Keep in mind that once you drain the distilled water solution there will still be an amount of water in there and if you use a 50/50 pre-mixed blue P-HOAT coolant the end result will be a higher freeze temp due to the water that was still in there. IMO, the color of the P-HOAT fluid does not matter at all. Whatever wally mart has on sale is what I use. Do you think it would raise the freeze temp enough to make a difference even if I got most of the water out? Link to comment Share on other sites More sharing options...
Max Capacity Posted September 24, 2020 Share Posted September 24, 2020 Have you removed the green coolant yet ? If no. I would not put the blue stuff in. Just stay with the green. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
59ctd Posted September 24, 2020 Share Posted September 24, 2020 Do you think it would raise the freeze temp enough to make a difference even if I got most of the water out? I was enough worried about it that I disconnected one of the heater core hoses and blasted air through there to force any water back to the engine block so it could drain out as much as possible. I don't disagree with Max - the green coolant works just fine too. Link to comment Share on other sites More sharing options...
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