overflowing expansion tank - JeepForum.com
LinkBack Thread Tools
post #1 of 6 Old 08-27-2004, 08:51 AM Thread Starter
Registered User
Join Date: Jan 2004
Location: North Texas
Posts: 22
overflowing expansion tank

.hey guys.
my sons 92 xj is starting to puke water from the overflow tank. i did a search but nothing helpful came back.
it doesnt seem to be overheating, drive & idling temps are normal. however, when the engine is shutt off, out it comes. the first time we noticed it the puke was white & foamlike, coupla times after just watery. seems there isnt a lot of antifreeze it there.
ideas on what we should look into first? have it flushed? new t-stat? water pump? or radiator?
thanks, we're baffled by the foam!

rokclimbertx is offline  
Sponsored Links
post #2 of 6 Old 08-27-2004, 10:08 PM Thread Starter
Registered User
Join Date: Jan 2004
Location: North Texas
Posts: 22

gonna pull out the t-stat and see what that does first as soon as i can find a place that has gaskets... still looking for ideas on why this is happening... thanks!
rokclimbertx is offline  
post #3 of 6 Old 08-27-2004, 10:31 PM
Registered User
Join Date: Aug 2004
Location: South Bay Los Angeles, CA
Posts: 2,534
Suggestion if you can't find a gasket: try using hi-temp silicone in place of gasket, it works well. just use a good brake cleaner to clean ALL crud, grease off of metal surfaces, and let it dry a couple of hours after boting back together before refilling coolant and starting engine. Use only enough silicone to do the job, it does not take much.
BrunoS is offline  
post #4 of 6 Old 08-28-2004, 01:00 AM
Senior Member
coppertop71's Avatar
1990 XJ Cherokee 
Join Date: Jun 2004
Location: Vancouver, WA
Posts: 953
You can try to change the T-stat and see what happens but if you want to solve the problem for good get rid of the pastic expansion tank. Here is a link from one of my earlier post with a picture of what I have on mine. If you can find a machine shop show them a picture and see if they can make one cheaper than the $140 or so I had to pay.

The white foam is probably caused from air bubbles from boiling water in the head. The plastic tank doesnt hold in pressure to increase the boiling point of the coolant water begins to boil inside the head probably near the #6 cylinder and floats the air bubbles up through the system.

My link to replace the plastic tank

2006 Jeep Wrangler X, 4.0 4:11 gears

'90 Cherokee XJ,W/'91 4.0L reman/ 3.5" RE lift, W/31" M/S tires, 4:11 Gears W/Speedo gear change/ Aluminum Coolant Tank
A/C Conversion/Home Built Roof Rack/K&N Box Filter
Derale 15" Rigid Radiator Fan PT# DER-17415, through Summit W/2"X5/8X5/8"" spacer

Jeep Pic's
coppertop71 is offline  
post #5 of 6 Old 08-28-2004, 07:43 PM Thread Starter
Registered User
Join Date: Jan 2004
Location: North Texas
Posts: 22
update... went and had the radiator flushed and pressure checked... cooling system came up fine but the rad. cap was bad... replaced it and all seems to be well...
rokclimbertx is offline  
post #6 of 6 Old 09-08-2004, 08:35 PM Thread Starter
Registered User
Join Date: Jan 2004
Location: North Texas
Posts: 22
Update Cont...


after a few weeks of good running it's back... the strange foamy overflow... not everytime the engine runs though... here's what happened today:

son was on his way home from work, stopped at a friends, turned the engine off and immediately heard the foam dripping from the overflow tank... after letting things cool down we drove it home and let it cool before taking the t-stat out (which we never did)... went out to pull it and we popped the rad cap to see if it was full, it wasn't so as we were off gettin a jug of water the foam started pouring out of the radiator itself... got the jug, poured water in until full which stopped the foam... rad cap back on and watched the temp gauge... heats up to almost in the red, fans kick on & cools back to 210... over & over 3 or 4 times then gets into the red and we shut it off... an hour later the kid leaves for home on the way there he says it did the heat up/cool off thing all the way home... come to a stop, heat up... start moving, fans kick in and cools off... 5 or 6 times then as he's pulling up to house it gets in the red...

tomorrow we are pulling the t-stat to see if that will keep the temp down but thats obviously not the problem... ideas? suggestions?

thanks for the help! anyone goin to moab next month for the NAXJA thing?
rokclimbertx is offline  

Quick Reply

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
engine coolant overflowing m_w_m XJ Cherokee Technical Forum 6 08-04-2005 05:19 PM
A/C Expansion Valve SmittysXJ XJ Cherokee Technical Forum 4 06-29-2005 09:14 PM
How do you fix an expansion plug leak? GDSQDCR MJ Comanche Technical Forum 2 06-26-2005 02:01 AM
Resolve your overheating problem on expansion tank cooling systems coppertop71 XJ Cherokee Technical Forum 3 07-22-2004 02:30 AM
coolant overflowing........... jerryhipp XJ Cherokee Technical Forum 3 10-25-2002 10:01 AM

Posting Rules  
You may post new threads
You may 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 On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome