I have a 2000 wrangler sport 4.0 with 94000 miles and i was changing the oil and it was very dirty, and then i checked the coolant and it was very dirty black, so we flushed it out with water then then put new coolant in and after it cycled through it was completely black again and we had it running and the radiator cap was off and we could see the coolant raising up to the top and going right back down (some one told me that could be a blown head gasket). what do you think??
04-28-2013 09:31 PM
When water and oil mix it makes a nasty milky goo. Was your coolant oily or just dirty?
04-29-2013 11:22 PM
Yes it is pretty oily.
04-30-2013 05:24 AM
Head gasket is a probable cause.
04-30-2013 07:04 AM
Oil gets black with normal use as long as you dont see metal particals or it looks like a milkshake ( literaly when coolant mixes with oil it looks alot like a Wendy's Frostie ) Your coolant turning black is a concern though, I'd suggest getting a block tester and checking the system. Sounds like you have a cracked cylinder head or head gasket leaking combustion gases into the cooling system.
Here's a link the explains more: Head Gasket or Combustion Leak Test Procedure (Gasoline Engines Only)
04-30-2013 07:19 AM
Is it an automatic? If so, the trans fluid runs through part of the radiator. Could be a crack in the radiator letting burnt trans fluid mix w/the coolent. If your oil is not looking like chocolate milk, and its an auto, it could also be this.
Could also be hoses wearing. If you pull a hose and wipe the inside with your finger and its all black... theres your culprit.