My 02 Buick LeSabre has oil coming from the radiator into the coolant reservoir. Just recently I had a new motor put in to fix the issue. What would be the best/proper way to flush the radiator? It has a new water pump and thermostat.

  • Hi and welcome. I'm having a hard time understanding your question here since it lacks formatting and punctuation. Could you please edit the post to clarify the question?
    – JoErNanO
    Apr 18, 2016 at 8:51
  • Mike, I have updated your question to make it a bit clearer. If this doesn't capture exactly what you were trying to say, please feel free to update. Apr 18, 2016 at 11:11

2 Answers 2


Use a coolant flush kit

You can add a 'T' to one of your radiator hoses that allow you attach a garden hose to your cooling system.

Once you have added the 'T' to your system you can run your car and the garden hose simultaneously in order to fully circulate the fluid in your cooling system as well as flush out all of the contents of the system to ensure that any oil in it is completely removed from the system.


Flush it out with a hose (ordinary garden hose will do fine), backwards - so that the water flows though in the opposite direction to which it would do in normal operation. Generally they flow from top to bottom, so you want to flush it from bottom to top - it's often easiest to take the rad out and turn it upside-down for this. Keep going until the water comes out clear.

  • I believe that would make it pretty difficult to properly dispose of the oil-coolant-water mixture. Apr 18, 2016 at 12:36
  • 2
    Indeed it does, but you don't want the stuff that's being flushed out going into your engine, as it'll be full of dirt and crud that's been dislodged from within the radiator.
    – Nick C
    Apr 18, 2016 at 12:40
  • 1
    I agree and also add some low suds detergent, such as dishwasher soap. In my experience this is the only way to remove oils from cooling systems. Apr 18, 2016 at 16:25

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