Engine coolant change question
 

Hi, this weekend I am planning on changing the coolant on my 05 impreza sti.this will be my first time doing this. Looked on the internet so many different ways and not clear if you ask me. Questions are can I drain the whole sytem from the radiator drain plug? Can I get to the drain plug without jacking the car up? Cheers

Up for interest

Yes, drain from the rad drain plug, or remove bottom hose. Set heaters in car to hot while it drains, leave them there.

Inspect rad for the core turning to dust, if it's bad, replace it, internet ones are fine.

Use a decent quality anti-freeze, as at a motor factor for one suitable for an alloy engine and having anti-corrosion added. Dilution is usually 50/50.

Replace plug or bottom hose!!!

Remove the rearmost pipe from the metal header tank on top of thengine, remove the cap from said tank. Jam a funnel down that hose and fill SLOWLY via the funnel, do NOT allow it to gulp.

Watch for the header tank to fill, once it reaches the top, remove funnel and replace that pipe.

Now, with cap still off, start engine and allow to warm up until fan comes on. Watch for bubbles, top up or mop up as necessary.

Once fans start, switch off, replace cap, drive round block, leave to cool.
When cool, remove cap, check level, top up if necessary, replace cap, job's a good'un.

It takes a while, but bear in mind, THERE IS NO KNOWN WAY TO BLEED THE SYSTEM IF YOU AIRLOCK IT.

Needs to be jacked up and under tray removed. You cant get every drop of the old stuff out just from the radiator drain athough the amount left in the block etc wont cause a problem. If you really want it all out then its going to mean refilling with water. Running the engine and draining again. Will probably have to do this a few times to remove every last trace of the ild stuff

Cheers feel like im getting proper information now and the step by step is much appreciated Alcazar. What coolant would you personaly recommend.i no its got to be allyminium freindly but some bottles just dont get down to the important info.Turbotits do you recomend jacking the backend of the car up aswell.only got front axle stands but read something about car needs to be level? Think im going to flush the system with water to get all the old stuff out.how long should I run the engine with just water in?

Just stood running with water should be fine for as long as required in this weather, jacking up just the front should be sufficient

Jacking the front up will raise the car so the engine is pointing front up. If you want to flush the block through it would make more sense to remove the thermostat and jack the car up off the rear diff. Just use a hose pipe on the top rad hose.

Take the rad out to flush it through, there's only the hoses and 2 brackets that hold it in place.

Just front up should be fine. Its suprising how long it takes to get every last drop of coolant out. Mine had green antifreeze in it. When i changed it two years ago i wanted to flush it as didnt want to mix colours. I flushed it and ran it 3 times with water. Refilled with pink stuff and still could see particules of green stuff. Ive since had a bottom hose replaced and header tank at different times. Both times i drained the system and refilled with new stuff. Im lucky not to have to pay for my antifreeze.
I still see the odd glistern of green mixed in with the pink stuff.

Another quick question. Car hasnt been drove or even turned over since saturday.checked the radiator cap and its full to the brim but the resevoir tank has got coolant in but it is below the min mark.
Never checked the coolant level since ive had the car till saturday.
Does this mean the coolant is seriously low and will cause damage if I try and drive it around untill I change coolant. Thanks for advice am not clued up on cooling at all

No, it's fine.

I've never bothered removing every last drop...unless your collant is seriously fekked or contaminated, I'd just do as I said.

As for make, just find a decent motor factor, ask there. should be cheaper than a car shop and certainly cheaper than HellFrauds.

Cheers for all the advice, going to do it sunday aslong as the weather is ok.

This might not be the best method for refilling, and I'm no mechanic but the method I have used for a few years with my classic has worked fine with no problems.

Once it's all emptied out on level ground, tighten up your drain plug or hose, Jack the car up on the offside front by a good few inches, and fill slowly from the header tank, bubbles will glug and vent etc etc until your full. Lower the car back down and top up the remainder, again slowly.As alcazar says, then fire her up until the fans come on and top up etc.

My theory (being a plumber) is that by douing it from the highest point, it will fill the radiator "backwards" and thus vent itself of air by itself to a certain extent.

As I say, it may not be the best way, but it works for me.

:-)

The glugging you describe is air escaping...having been trapped. You don't need much to remain trapped to airlock the system.

The best way to ensure no air remains trapped is to fill from the bottom...which is what my method does.

Yes, older plumbing systems filled from the top...but each rad had an air=bleed valve.

Don't modern systems fill from the boiler?

The original radiator on my bugeye has decided its had enough after 13 years so will be fitting a new japspeed one tomorrow.

Will be using the Alcazar method for re-filling the system and never done a rad and coolant change before,so should be interesting.

https://cimg4.ibsrv.net/gimg/www.sco...5a08d83995.jpg


A decent sized crack on the old radiator which does leave a bit of a mess under the bonnet.

New Japspeed rad now fitted with no major poblems apart from some difficulty getting the bottom hose back on and i'm pleased to say the Alcazar re-filling method worked a treat.:thumb:

"Holy thread revival Batman" etc!!

I've got a set of new coolant hoses to fit on Monday and was planning on trying to change them as quickly as possible to avoid loosing too much coolant (as it was only changed a few months ago!)
I will refill using the rear header tank hose as suggested, but should I leave the car on the ramps (I will have to put it on ramps to get access to the bottom hose!) whilst I refill and run the engine, or is it best to put it on the ground?

Don't fek about, you'll trap air.

Drain it into an old washing up bowl, £1 from a pound shop, then refill properly.

Ok then, I won't try to save the coolant, lol!
Should I have the front of the car in the air and how much coolant do I need?

Drain into washing up bowl and reuse???
Front down.

Coolant is around 7l, but needs to be diluted 50% with water, so 3.5l. My own experience is that you get about 5.5-6l in.

That's cool, I'll replace it for what it costs.
Cheers bud, I feel a bit more confident about doing it now.

Easy job, use new stainless clamps, or new jubilee clips, take your time filling.

Thanks mate, I've got new jubilee clips ready for the change.
I've done this job a million times on my old car and never had a problem, but for some reason I'm petrified of touching this car!

I used to be.

Now the thing that worries me is having to remove say, six bolts, and knowing, just KNOWING, that the sixth one will round off. or snap, or something....That's 18 year old cars for you.

Wheeler Dealers always cracks me up as he NEVER has problems from a far older car........

Well, I've started and it's draining as I type. But I've got three hoses that I can't see in my engine bay! Do you know where they go?

https://cimg7.ibsrv.net/gimg/www.sco...9394a75a45.jpg

Well, they're in:

Attachment 38269

Attachment 38270

My top hose doesn't seem to fit quite right though. Should I trim it, or will it be ok:

Attachment 38271

Where did the spares go?

not read the entire thread but this works for me:
park car on level surface.
rad cap off.
disconnect bottom hose. leave to drain. it take a while to get past stat.
connect bottom hose.
disconnect top top.
fill rad SLOWLEY
fill block SLOWLEY
connect top hose.
top up header tank SLOWLEY.
run car with cap off till it over flows.
cap on.
top up by battery.
Job done.

No idea fella, they're on my workbench!

Will work with a bit of luck. Sadly, both rad and block are being filled from the TOP, which is the no-no. So not 100%.

I used alcazar's method and it worked perfectly. Refilling can take a bit of time, but I'd rather that than an airlock.