Hello I have an old Subaru 2008 Impreza, it was a used car I bought from someone a few months ago. When I emptied the coolant out of the radiator (I had to do it from the hose because the plug was stripped) about a bit over a gallon of coolant came out. Reading the manual, it says that you need to put in 2 gallons of coolant. So I decided to start filling it up with a radiator flush + cleaner and then give it distilled water , but it only took 1 gallon of distilled water, again, which I thought it should be 2? Even while running the car, I could still only fit 1 gallon of water. I’m about to drain it out and put in the new coolant, but am I doing some thing wrong? Shouldn't I be able to put the 2 gallons that is required on the manual? Why am I only getting 1 gallon out and can only fit 1 gallon in? I’m a newb with cars and this is my first flush. Any help would be appreciated, thanks!

You are draining the radiator..... Lets get educational:

1. What other items contain coolant but were not drained? Format your response as an essay. One page, college ruled, double spaced. 

2. Write at least two paragraphs, in the argumentative essay format, convincing the reader that radiator flushing a 2008 Subaru is both useful and necessary. 

GD

Hello and thanks for your response. 

I came here to seek some help, so I was expecting that, I didn’t know I needed proper formatting for this but now I do. Also I don’t know much about cars, what I’ve learned is through friends and YouTube, the very basics. I’m learning.

I bought this used car and noticed that the reservoir was dirty and that the coolant was on the low end. I though that perhaps doing a flush would be a good idea as I didn’t know how well the owner took care of this car.

Besides the radiator it appears that the engine block also holds coolant but this is just a guess from watching 1 tutorial, all other tutorials I watched did now show me to drain the engine block. Please correct me if I’m wrong and thanks again for taking the time to reply.

edit: my problem is with the manual, why is it showing me how to drain only 1 gallon of the coolant but tells me to buy 2 gallons before draining it the way it is shown on the manual. Shouldn’t the manual have shown how to drain all 2 gallons it it’s making me buy and use 2 gallons of coolant? 

Edited July 5, 20205 yr by CtrlP

I'll make this easy. Don't flush it. It's not necessary.

If the radiator is original, just go ahead and throw that right in the trash. Order a radiator (Koyo), and new hoses from the dealer.

If you really want to drain it all, pull the thermostat  housing off the water pump. And pull the plugs off the bottom of the engine block. 

If the car hasnt had a timing belt in 10 years or 105k then it needs to be done along with the water pump. At which point all the coolant gets drained again. 

Subaru's aren't hard on coolant. It pretty much lasts forever or till the water pump shitz the bed. 

Manual..... what manual are you using? 

Let me set you straight on something - people that do this for a living (mechanic's, technician's, etc) don't consult manuals for changing coolant. We just don't. And generally you drain what's in the radiator and put in new. Whatever that amount is.... not all that important really since all the fluids we use are in bulk. It is what it is. And unless the coolant is REALLY nasty (like rusted shiz), changing 75% of it is perfectly acceptable to renew the additive package (zinc and stuff). 

Don't worry about the coolant. Worry about the radiator and the timing belt. Those are what's going to strand you. 

GD

Edited July 5, 20205 yr by GeneralDisorder

yup, the radiator itself will only hold about a gallon. the entire system holds the 2-ish gallons - block, heater core, etc.

the "flush" stuff is not necessary, at all, as already noted. I would be more concerned about why the reservoir is dirty - what kind of dirt? oily dirt? just dirt, dirt? and how dirty is it? oily dirt can suggest other, more serious problems..

The timing set is far more important to keep things running reliably. unless you have verifiable proof it has been done, it needs to get done asap.

for a proper factory service manual, go here, locate your model and year, and download: http://jdmfsm.info/Auto/Japan/Subaru/

if the overflow is milky/dirty, take it out, bust up some ice cubes and put a coupla handfuls of the biggedr chunks in the bottle and shake the 4311 out of it. Try that a coupla times if the filth is stubborn inside.