I prefer to do it more often and keep things fresh. While there surely is some benefit to flushing the whole system, I haven't necessarily seen it.
I agree with Bill's concept for the most part, but mine is a bit more "expensive", foolproof and time-insensitive...
I drain the radiator (or if feeling especially lazy, just suction out the coolant in the pressurized expansion tank on cars that are set up that way). On some cars with an integrated expansion tank on the radiator (some BMWs for example), you can actually "suction" out all coolant through the expansion tank, out of the radiator.
Anyway, drain the coolant from the radiator, refill with 50/50 of the right chemistry. Close it up, and drive. Some time in the future, repeat.
I do this when I think of it and have time, and shoot for a few good turnovers every 36k or so. I generally do at least one exchange every year to keep things fresh.
Since Im feeding 50/50, there is never any worry of an improper mix - it is just right there, correct as required. A gallon of distilled and a gallon of concentrate provide you two gallons to use, and will likely last you 2 years.
I also run Schaeffer's clean and cool in my cars.
Hey that was fast.Thanks!May I ask what is the conditioner?I have never heard of that.
Anytime you change the coolant (every 30k) you have to use the conditioner from Subaru no matter the year or model.
Here is a link where they discuss what you have to use plus the conditioner. info for subaru coolant
and this is it...
List price on the Subaru conditioner is only $3.96. But the genuine Subaru coolant is $24 per gallon. I went with Subaru coolant, but Peak Global (must say Global on the jug!) should be OK, if you can find it.
On my Subarus, I get 5 quarts out on a drain, system capacity is 6.7 quarts. I don't bother with flushing or drain/fill/drive/repeat cycles. But I do drain and fills every 2 years. Your choice, though, a flush with distilled water certainly won't hurt anything.
I'd simply drain it, and replace with the proper mix of coolant and distilled water.
Might as well give it a shot of the Subaru sauce, too.
This is best if there are no problems right now - no sludge or corrosion internally.
Just drain and fill for good maintenance.
Subaru wants us to to use the conditioner. It says to use it in the owner's manual, the maintenance schedule, and the FSM.
Direct quote from the maintenance schedule:
"To prevent cooling system leaks, always add Genuine Subaru Cooling System Conditioner (Part no. SOA635071) whenever the coolant is replaced."
Subaru had a problem for a while with leaking headgaskets. The Phase II 2.5l engines leaked externally - coolant would drip out. The conditioner was a "bandaid" and seems to help some, but with redesigned headgaskets since 2003, the HGs haven't been a common problem. Not sure if the conditioner is really necessary, but they still want us to use it.
The Phase I 2.5l engines had a different kind of HG problem: combustion gases from the cylinder would force their way into the cooling jacket. No conditioner will fix that. Properly done repairs with the latest revision OEM HGs seem to hold.
I'm guessing you're not familiar with the head gasket problems on Subaru four cylinder engines. Am I correct? [/quote]
Nope. Wow that is disturbing if it is a widespread problem. So much for Subaru quality.
We don't know if there are specific materials or problems with the Subaru that the mfr wants to address with the special sauce.
A few dollars extra every 2-3 years is OK by me.
It is rare that a mfr will call for something like this, so I'd put some in.
There is too much we DON'T know.
Wow, some of you change coolant often, at least compared to what my '06 Camry manual says. The manual says the factory fill of coolant is good for 10 years. After that, replace the coolant every 5 years with special "Toyota Super Long Life Coolant." Is the manual too optimistic on how long you can wait? I mean car manufacturers don't always get it right when it comes to coolant, ie, lawsuits against GM.
Actually, the Camry maintenance guide says to replace the initial factory fill of coolant after 10 years <i>or</i> 100,000 miles, and thereafter to replace the coolant every 5 years <i>or</i> 50,000 miles. How realistic is this for Genuine Toyota Super Long Life Coolant?
Someone at Geocities wrote:
"Some sites say "Do not run the vehicle while flushing the system. Even though this would likely do a better job, the cold tap water running from your home may cause aluminum engine components to warp as the engine heats up." [end quote]
Who would use cold tap water with all the minerals in it? But even when using store-bought diluted water (or even pre-diluted 50/50 coolant), I guess a problem could still arise if you were storing the diluted water (or 50/50 coolant) in your cold garage during the winter, and decided to do a drain-and-fill. Even during the winter, the engine will warm up, but the gallon of diluted water (or coolant) might be rather cold sitting in the garage, possibly leading to aluminum warping--or so I'm purely speculating.
I guess like motor oil, you need to keep your diluted water and/or coolant warm and sound inside your house, like under your mattress.