Oil in the coolant

Is it motor oil or trans fluid? The trans cooler is an integral part of the radiator and can leak. Make sure there is no issue with the fluid in the trans and let me know what you find.

no water in oil, does not overheat until running several minutes, however plenty of brown (not red) oil floating in water. Just had air intake manifold butterfly motor worked on by local mechanic (last week} but not sure I can trust. Oil clear, transmission fluid clear

Hello,

This means the oil cooler inside the radiator has gone bad and is leaking engine oil into the coolant. Here is a guide that will help you get the problem fixed.

Also see if there is an engine oil cooler by the oil filter which can leak too.

https://www.2carpros.com/articles/coolantantifreeze-in-the-engine-oil

and

https://www.2carpros.com/articles/how-to-replace-a-car-radiator


Please let us know what happens.

Cheers, Ken