Cannot drain ALL coolant

[Diamondbackdude]

Posted 5 hours ago
Hi

I changed the coolant in my 08 Avensis this weekend. Opened the drain on the radiator and also connected a piece of tube to the engine engine block drain and opened that.

I got about 4l out of the radiator and when I opened the engine block drain nothing came out. I fired it up for a few seconds and got about half a litre it of the engine block.

I connected a small air pump to the overflow in the expansion tank to push that through the radiator.

I set the blowers to hot too.

So all in all I got 4.5l out however the capacity is meant to be 5.9l. I tried squeezing the hoses etc to get more out but that was all I could get.

At this point I just thought well it will have to do and filled out back up.

Am I missing something? If I took it to a garage to get this done would they really go removing all the hoses, thermostat etc to get every last drop out?

Another thing is the engine block drain doesn't seem to be that near to the bottom of the engine for it to be able to drain out...?

[Dogwatch]

Have you set the heater controls to max? Coolant can be trapped in the heater otherwise.

Does it really matter about the couple of pints still (possibly) lurking in the depths of the system?
If yes disconnect the radiator bottom hose, drain and replace, with a new clip.

If the radiator end of the bottom hose is difficult to get to, disconnect at the engine block and push a tube down to siphon out any remainder.

And finally, don’t chuck the waste down the drain take it to the tip for proper disposal.

[Smint]

For getting it all out shove a hose pipe in all possible holes and let the water flow through in all directions.

Getting it all out depends really if you are changing types of coolant, because the old stuff and OAT far as i can recall don't like each other and can form a gel which won't be very handy, if you're replacing like for like, typically Toyota Red coolant which is good stuff, then don't worry about flushing every drop out.

[trickywoo]

My favoured method is to do a couple of changes a few months apart.

Just drain the rad. You will have 4l new in 5.9 first time. Next time you get another 4l of new in the 70% new mix. That’s good enough and not too wasteful if you use Prestone which has a ten year life and is pretty cheap.

[Chris32345]

It will be trapped in the engine block as it's unlikely the have a drain point at the lower point of the coolants pathways

You'd probably need to remove the water pump the drain it all out

But what you have changed will be more then enough on a good condition engine

[Buzz84]

Not really something a DIYer would have and maybe even a little specialist for a garage to have, so this post is of very little use.
But as a interesting (possibly?) bit of info, If you really needed to get it out you need a vacuum pump, connect it via a sealed cap on the header tank and the reduction in pressure reduces the boiling temperature of the coolant, it boils and the vacuum sucks the coolant vapor out. (Problem is then that the coolant vapor then condenses in the vac pump and doesnt do it any good at all)

The vac pump can also be helpful for filling as I'd there is a vacuum in the system when the coolant is introduced, you can't get air bubbles. Meaning no bleeding is needed.

[dhutch]

Just flush it a few times with clean water?

[Diamondbackdude]

Thanks for all the replies.

Problem with flushing with water is that the coolant I bought is the Toyota Pink super long life and they don't do a concentrate version so if I have distilled water left in from flushing it would dilute it.

I took it an independent specialist a few years ago and they said that whilst Toyota say the pink coolant lasts 10 years/100k in their experience it lasts a lot longer.

As my car has now done 130k I thought best to renew it. As has been said replacing 75% of it should be fine to rejuvenate it there's nothing wrong with the car it's in good condition.

I actually like the idea of doing it twice as was suggested but I'm going to resist the urge to let my OCD get the better of me particularly as the Toyota stuff cost £35 for 5 litres!

[Krikkit]

I'd fill it back up with clean water, run it for a minute, then drain again.

Once drained refill with your Toyota coolant - it'll be slightly under-mixed, but I'm assuming you won't be using it at the extremes of temperature that it'll go down to so it won't matter. If you were you could add more concentrate later (although another source)