Coolant, difference between brands?

I'd rather not use cheapo fluids for the sake less than £5 difference!
 
Coolant shouldn't disappear unless it's boiling over... my MX bike used to lose coolant, but that was because it was a highly strung race engine that used to spend a fair amount of its time burping out various fluids through breathers...
 
It gets hot enough to evaporate even on all cars though which is why you never open the cap until the car has been off for the system to cool down a bit
 
It gets hot enough to evaporate even on all cars though which is why you never open the cap until the car has been off for the system to cool down a bit

Isnt that due to the 1bar or so pressure rather then "evaporating"

Also doesnt the extra pressure also change the boiling point?
 
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Water can escape through the plastic cant it? In the same way water enters the braking system over time and the fluid has to be replaced.
 
That leads me back to what the Snows BMW service dept guy told me on the phone back then about it escaping over time through microscopic holes so eventually will need topping up!

Isnt that due to the 1bar or so pressure rather then "evaporating"

Also doesnt the extra pressure also change the boiling point?

Well you will get steam burn injuries if you open the coolant cap on a freshly driven engine so therefore evaporation!
 
Lets be blunt about this.

If your coolant system is properly sealed and you lose coolant, your car is in some way defective. There is no normal 'evaporation', you dont lose some 'through the hose'.

It's either broken, or it isn't losing coolant. There is no middle ground.
 
I have to top mine up every 2 - 3 months and normally just top up using water.

I replaced most of the hoses last year, but it think the one from the expansion tank to the rad is where its seeping out, so im going to buy a new one then do a complete flush and refill on mine.

As for brands, I just use whatever is in the shed! Never had a problem yet.
 
But as I updated today^ the cap wasn't closed properly 2 days ago hence the rapid loss of it so must mean it wasn't closed (but to a lesser degree) the last time which attributed to the slower loss of some coolant.

If something was broken then there would be a sign, a leak or engine light or even odd driving behaviour but there's none of it and my engine bay is cleaner and dryer than the outside of the car right now.

I have MOT booked for the 18th, I'll sure mention it but don't expect them to have found any problems in the pre MOT checks they do. Anyway the problem has been solved ages ago, I was merely posting an update.
 
[TW]Fox;12638738 said:
You'll mention coolant at an MOT :confused:

Autotechnik can check anything you'd like them to during the checks - I did the same with my last car and they didn't find anything wrong back then and didn't get charged for it either.
 
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