Why Would My 2000 Buick Century Have Oil In The Radiator?

It could be one of 2 things. It could be that the transmission cooler is leaking through in the radiator. Most radiators also have a tranny cooler on the side. I had an older vehicle that did this back in the 80's. I had to replace all the hoses and flush the system repeatedly to get all the oil out. I also put an external tranny cooler on it and caped the plugs. All was fine after that.

The other thing is that it could be is a blown head gasket letting engine oil get into the water jacket or maybe a crack in the head or block. This requires you to tear down the engine and while you are there, might as well do a complete valve job. Much more work.

Which oil level is going down would be the best answer to take the right action. I hate to say it but it is usually the head gasket that fails.

Second Opinion: Motor will fail should captive cooling system experience an internal pressure greater than the cracked engine block and/or head gasket break or a warped, possibly aluminum head. Get an individual cylinder pressure test done. Do it now or be walking in the near future! Check for any engine leaks everyday & keep the coolant level filled and don't run the vehicle for long periods of time so to produce sustained high temperatures. Take an aspirin and call a technically knowledgeable garage in the morning. Then, call your bank to verify the amount of funds that are on standby for a new location to be at!

3.1v6 oil in the radiator

Blown head gasket or a cracked head. Neither is good.

There is a simple answer to that you have done a head gasket could be expensive

Why would my engine have bubble in motor we correct the water pump that my brother put it on wrong. Now it say check engine light came on