Added water to the cooling system

[craigdm]

Car is not being used much at the moment, but yesterday when I got in I saw the coolant warning light.
The expansion tank was low so I topped it up with water.
Didn't think anything of it until about 3am this morning when I remembered doing a coolant change on my MX5 for which I had to but specific pre-mixed fluid for it's 10 year scheduled change.
Suppose I have two questions:
1. Should I have topped up with a specific fluid, and will just adding water have exposed any risks?
2. What is the schedule for coolant replacement, and is it an easy home project?

TIA

Craig

 

[colb]

Topping up with plain water will obviously dilute the coolant mixture you have in the car but won't do any harm in the short term. You can buy a coolant tester to check what temp its capable of dealing with with regard to freezing protection. You could have a premixed coolant on hand for topping off and keep it in the garage rather than topup with plain water. You must ask the question of why has it needed topping up, check for any leaks in the system.
Usually a change of coolant every 2 years should suffice but an annual check with a tester before winter is always advisable.

Changing coolant is a DIY task, the only issue likely to crop up is bleeding the system when you refill, get the front of the car as high as you can when refilling and have the heater controls set to Hotm so the coolant flows through the heater matrix to get the air out of it. Initially run the engine with the rad cap off to bleed the air out, put the cap on after the level stabalises then continue to bleed using the bleed screw till no more air bubbles are expelled. Keep an eye on the heater performance for hot air and the temp guage sitting at 12 o'clock is stable with the engine running.

 

[flybobbie]

Just running engine won't bleed.
Need ignition on, foot on accelerator 10 seconds and the electric pump runs for about 30 seconds.
Just repeat until any gurgling stops and water flows free from the small pipe on the side of reservoir.

Drain plug is the blue screw thing bottom left of radiator.