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Hi guys,

Dont know if I really want to hear the answer to this one. I have a turbo NA, got the engine rebuilt about a year ago (connetic head gasket, ARP studs, rehoned cylinders, checked head etc) ................before my trackday yesterday I gave a small top up to my radiator water. The water was a clear red (the coolant Im using is red) When checking the radiator today, the water is still red but very cloudy, you cant see through it like you could yesterday. I cant see any oil in it. My engine temps stayed good on the track yesterday and didnt go high.
Can anyone help me, Im really hoping its nothing major

cheers Nicky

I guess maybe the radiator cap is not working properly or something that related to the pressure is not working right. Therefore the coolant that already inside the radiator will run back to the coolant box, because the coolant in the radiator is not fresh and cloudy so its causing the coolant in the coolant also cloudy. Just my guess, did you hear any "bubble" sound from your car after its get really hot?

When the car gets really hot I do usually hear a slight bubbling sound when the engines turned off. It confuses me why its gone from running with clear coolant to turning cloudy all of a sudden after my track day yesterday.

I hate to say it but probably a pinhole leak from combustion chamber to water jacket through blown head gasket.
Things to check for:
- coolant loss
- coolant will often appear milky due to presence of superfine bubbles
- take the cap off and rev it, coolant will often foam (rather than just flood) out the cap hole
- if you use glycol in the coolant then there may be a sickly sweet smell of cooked glycol in the general vicinity of the car
- compression test; leak between 3 and 4 is most common if you don't have a coolant re-route

edit: bubbling after switching off is called afterboil, not normally a problem, you're more likely to hear it when you're worried.

Good news, the mechanic gave it a Co2 test and pressure test. All came up good. I put some of the cloudy radiator water in a jar and let it settle for a couple of days, its just gunk/rust out of the engine. The engine did have a small amount of rust in it when I got it to rebuild as it had been sitting around for a while. I think the water may have been like this since the coolant was put in with engine rebuild, but hadnt checked it directly after a track day, only the day before a track day so by then it settles and looks clear (as it does now). May do a coolant flush and refill before radiator starts blocking.

Glad to hear its nothing tragic nicky

Cheers
Dale

Yh, thats a good result.