Having had to half fill my rad with plain water, what's the best way to drain it before adding more coolant?

mrtask

Well-Known Member
This afternoon my car began to suddenly expel hot coolant. Billowing plumes of sweet smelling steam from the gaps between the bonnet and wings. Pulled over straight away. Engine temp up to the red! The electric fan had ceased to function. It had blown its fuse. The ever so helpful AA chap diagnosed an exposed bit of wiring adjacent to the fuse, up behind the passenger glovebox, which was arcing to the metal bulkhead. Some insulating tape, a new 15 amp fuse and a couple of litres of water got me back home.
So now I need to drain the diluted mixture back out and refill the rad with the proper coolant, right? Not all that keen on draining it by the drain tap at the bottom of the rad. Always very messy! Can I syphon or syringe it out via the filler neck? Or shouldn't I worry about the coolant now being too diluted? I didn't think to ask the AA guy if he was topping it up with distilled water, but I imagine it was just plain water. What are your thoughts, chaps?
 
Oh no!

I would siphon some out the rad and then top up with antifreeze, I have done this before when removing the rad and its easy if not the best fun when you get a mouthful. If you are worried maybe you could get one of those tester things and see what concentration of antifreeze you have?

I use water from the dehumidifier in mine, or failing that its tap water that's gone through a Brita filter jug (the water is very hard here). If it was only a couple of litres from the AA guy then I would think you should be ok.
 
Whatever means that you choose to remove or add coolant, please don't manage to swallow any as it is quite toxic.
Antifreeze Poisoning: Symptoms and Treatment (healthline.com)

The water added is not just in the radiator but is now throughout the entire engine. Easiest way to ensure a proper concentration is to drain the lot, radiator and engine (using the drain taps), then refill with the correct concentration. Easy as pi (mathematical constant) and then you can sleep easy knowing your engine won't corrode rapidly due to an inadequate coolant concentration.

Ron.
 
Thanks for your suggestions, fellows.
Ron, I appreciate your concern for my health! If I syphon, I'll use a hand operated pump. I don't want to ingest any coolant!
I'm not going to crawl right underneath the car and try and loosen the engine drain taps! They'd probably just snap off anyway!
 
Yes
I used it in my blue car, Classic Cool 180. I tried various ways of plumbing in a header tank in order to keep a full rad, in the end I settled on an overflow bottle and a double seal rad cap. I kept around 1 1/2" of Evans in the bottle, enough to cover the pipe from the rad and the Evans expanded quite a bit when hot, the bottle capacity was 1 litre. The rad always kept full to the brim. I never had any issues using Evans, it kept the 4.6 cool on road and track.
 
Having never had the luxury of drain taps on any other car, I love them.....as opposed to undoing a bottom hose and the inevitable drip..... drip..... slightly bigger drip.........(all landing in container) then Tsunami (missing container!) situation I am used to, a bit of aquarium hose on the tap, which I put through a hole made into the cap of a five litre container (needed two), and for the first time ever Ive managed to drain radiator and engine block without soaking everything else. I admit though, that like you MrTask, I was rather worried about them snapping off, but then relieved to see they behaved just grand, seem to be well made wee taps, and having long arms, was able to do them both from above - these Rovers seem well designed!
 
If you are worried, why not drain and replace all the coolant. Antifreeze is much cheaper that a replacement engine.
What is there to worry about?
Anti-freeze not strong enough to protect against expected frosts?
Not giving expected corrosion protection in an aluminum engine?
Risk from either should out-weigh the cost of anti-freeze.
 
Back
Top