What are the causes of oil entering your cooling system? What repairs can be done to fix this problem.?

Looks like antifreeze hasn't been changed in a long time and liquid is of brown muddy color. temperture indicator reads normal. no over-heating yet. Was told can not flush out cooling system until cause of oil leak is found. How costly would these repairs be?What are the causes of oil entering your cooling system? What repairs can be done to fix this problem.?
Just because it is brown doesn't mean that it's oil in the coolant. Coolant will usually turn brown due to rust deposits if it hasn't been changed in a very long time.





Have an experienced mechanic perform these two tests: first, apply a coolant system pressure gauge on the radiator or expansion tank opening. Have the engine run and see if pressure builds and fluctuates. If it does then combustion pressure is entering the cooling system indicating a bad gasket or cracked or warped head.





Second, have the mechanic probe the radiator or expansion tank opening with an exhaust probe. A higher than normal hydrocarbon reading indicates oil in the coolant.





You can usually see streaks floating across the water if there is oil in the system. You can always flush the coolant, it won't hurt anything. It's just that it won't solve a bad gasket, cracked or warped head or cracked block.What are the causes of oil entering your cooling system? What repairs can be done to fix this problem.?
is your anti-freeze orange or green if its orange then drain it flush the system and add new antifreeze you probably have a chevy car that's normal condition cause of the orange anti-freeze.but now say it was oil and it was brow-redish color then check you trany oil is it pink or red automatic transsmission cool the oil usin the radiator coolant like a heat exchange if that's crack then you'll see oil in coolant an coolant in trany oil. hope this helps you
Oil in the coolant would be floating on top and have a very distinct petroleum smell to it.





If the coolant is just a muddy brown color, it's probably just rust. Get it flushed and put in new coolant.
the place on the radiator where the transmission lines are hooked up to probably has a hole in it and you are mixing transmission fluid and anti-freeze together.
Probably a bad head gasket is causing the oil to mix with coolant.
IT COULD BHE A BAD HEAD GASKET OR A CRACKED BLOCK.