Coolant Flush

[Guss23]

Hello, I have had some strange issues with my car and I think I might have figured out why. Now, how to fix it....
My car is a 9,000 mile car that sat for quite a few years. Since I bought it I have chased a few demons but have it running ver good. One issue that I could not fix however is an oil leak. It is random however. I’ve noticed that it only happens when it has been run for a while and gets hot. The gauge shows that it’s not overly hot. I looked in the coolant overflow tank and the coolant was brown. After draining it has a brown sludge in it. I think that the heads are not getting even cooling. Has anyone ever flushed out the cooling system before? Any suggestions?

 

[1bad89]

I'll be putting my 160 thermostat back in so that's when I'm going to flush mine out. My car has 16k and I flushed it twice so far. Didn't notice much brown though. I never power flushed it. Just used a spray nozzle with water through the radiator and let it drain. Then 50/50 mix and let the thermostat open. Just basic stuff. But the oil leak is a different story. Been there before !!