brown water might be a sign of something else, it should be either blue or red depending on what colour coolant/antifreeze you have in there

they were very prone to cracking header tanks so it could be as simple as that (although the last time it took 3 weeks for one to turn up at the local ford dealer as the whole country was out of stock of them)

ask someone who you can trust to look at it and see what the problem is, it may well be more than the cars worth to fix or it might be a cheap fix, if you drove it overheating for any length of time it might have done more internal damage than you may first think

aa membership is sometimes worth its weight in gold