Dark/brown coolant after track day

[Somnambulist]

I was out at Silverstone on Sunday, and was running my 182 for just under two hours solid. I popped the bonnet at the end and my coolant (which was changed in November) had gone from a lovely vibrant pink to a very dark brown/black colour. No overheating issues or cream on the oil cap to indicate head gasket issues.

Someone has suggested the sustained heat has just lifted rust out of the radiator, but any other ideas or anyone had this before?

 

[dangerous dave]

flush it, hose out the rad and block, go again..

I've had to do it to my gtt's over the years..

 

[Somnambulist]

Great thanks! Will report back soon.

 

[MG cup]

If it does cloud up again I would be very surprised of it being a head gasket having never heard of one fail oil-water.

Where they can mix is on the thermostat housing gasket as it seals two oil galleries and a few waterways on the same gasket... Just something to bear in mind if a flush doesn't work.

 

[Somnambulist]

That's really helpful thanks. Just spoke to Terry at Two Techs who mentioned it may also be because I didn't give them Type D coolant when it was changed in November. Apparently you should only ever run Type D coolant and these cars aren't keen on water-mixed solutions, so I'll be picking some up tomorrow and changing it on Friday!