00 wrangler 4.0 coolant is very dirty black - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today

Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 04-28-2013, 10:21 PM
Thread Starter
Join Date: Apr 2013
Posts: 2
Lightbulb 00 wrangler 4.0 coolant is very dirty black

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??

c.busby94 is offline   Quote
Old 04-28-2013, 10:31 PM   #2
mrpotatohead's Avatar
Join Date: Jun 2012
Location: Happy Valley
Posts: 783
When water and oil mix it makes a nasty milky goo. Was your coolant oily or just dirty?

mrpotatohead is offline   Quote
Old 04-30-2013, 12:22 AM
Thread Starter
Join Date: Apr 2013
Posts: 2
Yes it is pretty oily.
c.busby94 is offline   Quote
Sponsored Links
Old 04-30-2013, 06:24 AM   #4
homebrwd's Avatar
Join Date: Mar 2011
Location: Ashburn, VA
Posts: 1,354
Head gasket is a probable cause.
homebrwd is offline   Quote
Old 04-30-2013, 08:04 AM   #5
flflash's Avatar
Join Date: Mar 2013
Posts: 519
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)
flflash is offline   Quote
Old 04-30-2013, 08:19 AM   #6
Founder, ThumbJeeps

WF Supporting Member
Chris Larabell's Avatar
Join Date: Sep 2009
Location: Mid-Michigan/Thumb
Posts: 4,062
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.

Founder, ThumbJeeps. Mayville, Michigan
"roads are boring"

1994 Wrangler YJ I6 4.0 H/O Auto 3 spd. 3:55 Gears
Chris Larabell is offline   Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 12:15 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, Gladiator, Mopar and Grand Cherokee are copyrighted and trademarked to FCA US LLC.
Wranglerforum.com is not in any way associated with FCA US LLC.