View Full Version : ok to dilute coolant?

06-20-2012, 09:04 PM
I noticed the coolant level in the barf tank was low, and being too short on cash to flush and replace it at the moment, my dad (who I got the car from) told me it would be ok to dilute the remaining coolant with water since it wouldnt freeze in summer. But i notice the sticker on the hood says not to do this. Is corrosion in issue? Or am I just too worried? I have been running on the diluted mixture for a few weeks now.

06-21-2012, 12:34 AM
A couple facts for ya:
Coolant is mostly "Ethylene Glycol".
In cold weather it helps prevent freezing (duh).
However, in terms of acting as coolant, water is the more effective coolant. E.G. IS needed even in hot climates though because it is there to stop rusting.
As long as you're sure you're not going to dilute it too much then you're better off with diluted coolant as opposed to low coolant. 50/50 mix is seen as ideal, but you can run it more diluted than that (like maybe about 30% Coolant BARE MINIMUM) it will just take longer to get up to operating temperature. Obviously you can run straight water if necessary but I would never let it go too long like that. Oh, and when you top up the burp tank, be sure not to overfill it!

06-21-2012, 12:46 AM
thank you good sir!

06-21-2012, 10:07 AM
Coolant does a number of things in the engine. It provides freeze and boilover protection, obviously. It includes corrosion inhibitors to prevent rusting, and it lubricates the water pump bearings. There isn't, actually, one specific ratio of coolant to water that everyone should follow. The ratio will change depending on your ambient conditions. If you live in an area where it gets very cold (like Chicago), then you might want to increase the amount of coolant to 60-70% of total (but no more or the freeze point starts to go back up). If you live where it gets very hot (like Arizona), then drop the coolant to 20-30% of the total and throw in some Water Wetter too. If you need to know what your mix is right now, you can get a hydrometer from the auto parts store for relatively little money and it will tell you.

If you run too little coolant, it will corrode the engine OVER TIME. If you run it that way for a few years, you will start to have a lot of cooling system failures, freeze plugs popping out, radiator leaks, water pump noise, etc., and you'll notice a lot of corrosion in the head and block at your next rebuild.

In other words, you should be fine.

06-21-2012, 07:32 PM
thanks snooz!