Topping up coolant
 

Evening all.

I am in a situation where I need to top up my radiator expansion tank and I only have access to water. Obviously using water is better than cooking the engine but when I return to civilisation will I need to have the radiator flushed or anything drastic like that?

The coolant level is currently at the bottom of the expansion tank and I will fill it to the 'cold fill' level.

I have a 2011 JKU CRD.

Thanks in advance folks.

Really don't think you have anything to worry about introducing such a small amount of water into the system. I have used water in many aluminium / iron vehicles. If you think about it, when a flush of the whole system is performed people use water and there is always some residual left in the system when it is refilled with the correct mixture.

Not sure about your Jeep, but on mine you can pop the small expansion tank hose off the radiator and hold it below the bottom of the expansion tank to syphon out the contents.
Just refill the expansion tank when you get home with antifreeze.

The real issue is to establish why you have used / lost the coolant

Just do it....... when you work it out its only a tiny % change in the overall coolant concentration.

You didn't mention what engine you have ( IMHO always a good idea if you want assistance ) so I'll guess it a Pentastar.

Its not that unusual for a Pentastar to need serious topping up every service or so..... but just keep your eye on it to make sure its not happening more rapidly - in which case you might have a leak.

JKU CRD.... Bottom of original post. :-)

My Bad...... in that case top it up and keep an eye on it. A little coolant loss is normal, but not lots on a CRuD.

Thank you all for for your replies.

I have been driving around the WA coast for several weeks with quite a few days in the mid 40 deg range and the temp gauge has been getting pretty high so I suspect the expansion tank has boiled over a little from time to time. There is evidence of this in the engine bay so that would account for the missing coolant.

I'll top it up this morning and continue on!

Sometimes many cars find their 'happy' level in the overflow bottle, and no amount of topping up will prevent them from always going to their 'happy' level.

It is only a overflow for heated coolant that necessarily must expand and as long as the rad is full then the engine is cold it doesn't really matter what is in the overflow bottle, because its only job is to catch overflow and return it to the radiator as it cools down.
In short you only need to add to the overflow bottle if the radiator is less than full when cold and simultaneously the overflow bottle's contents are exhausted.