Realised the other day that my coolant level is below the minimum mark on my MK6 Fiesta. Would i be alright just adding some deionised water to the fluid that's already in the tank or should i go and buy the ford specified coolant/antifreeze mix and just add that? General rule is always 50/50 coolant/water mixture right? or can you just add ready mixed coolant to the tank and not use any water? not sure whether the current fluid is just 100% coolant or if its a 50/50 water coolant mix thanks.

Should i;

1. Just add deionised water to the fluid already in the tank?
2. Buy a bottle of coolant and just add it to the fluid already in the tank?
3. Do a complete flush out to be safe? 

 

Personally I go for premixed OAT. If you accidentally put in too much water you can cause yourself problems, so I don't put in any water.  

Has it ever been drained and re-filled? I think Ford recommend that it's changed every 10 years (it's what I did on my W reg ST24, changed it in 2010).

I would just drain and refill with premixed or mix yourself with deionised water.

I am totally confused as to which coolant to use to top up 1998 fiesta.  Manual says Motorcraft super plus 4but can't find it anywhere to buy.  Fordspec is ESDM-97B49-A.  I read that you only have to replace it totally if it looks dirty...

I think it's generally quite cheap to replace coolant. For what it's worth, I'd rather flush the system and put all new coolant in for peace of mind.

23 minutes ago, jbell said:

Personally I go for premixed OAT. If you accidentally put in too much water you can cause yourself problems, so I don't put in any water.  

Cheers think I'll just get a ready mixed coolant and forget about adding ionised water 

18 minutes ago, Frembrit said:

Has it ever been drained and re-filled? I think Ford recommend that it's changed every 10 years (it's what I did on my W reg ST24, changed it in 2010).

I would just drain and refill with premixed or mix yourself with deionised water.

Not that I'm aware of, it's a 2007 model so perhaps it is due a flush and refill if the recommendation is every 10 years. Maybe a previous owner has just topped it up once/twice and now it's needing fresh fluid. Suppose ready mix will be quicker and easier and for an extra few £ it's the better option. Would you recommend just using coolant from Ford or have you used other brands like Halfords/TripleQX ready mixed coolant before?

I used Halfords last time.

Just to note:

Any antifreeze, whether ethylene or propylene glycol based, picks up heavy-metal contamination during use. For this reason, special care must be taken to dispose of used antifreeze. It's safer to have a repair facility flush your cooling system, since they are required by law to dispose of the material safely.

Most communities have procedures for disposing of hazardous waste; if you do your own repairs and maintenance, take advantage of these procedures. Don't pour coolant down your sink or into drains.

Just top it up with tap water...honestly, it'll be such a small amount it won't make any difference.

If you do want to change it, Fords pink coolant is designed to last 10 years.  Triple QX pink coolant is only designed to last 5 years...but for the price difference, you could change it again in 5 years if you even still have the car by then.

You can test the freezing point of coolant, which is the most important part, with a cheap tester from Halfords or the like.