99 Grand Cherokee overheating when in heavy traffic, with or w/o A/C on - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > 99 Grand Cherokee overheating when in heavy traffic, with or w/o A/C on

Savvy Billet LED Tail LightsWant to be able to SEE? DOT Approved Headlights for under We have FLASHLIGHTS! Great for your Emergency bag!

Reply
Unread 07-20-2009, 04:39 PM   #1
roxygirl25
Registered User
1999 WJ 
 
Join Date: Jul 2009
Location: Portland, OR
Posts: 1
99 Grand Cherokee overheating when in heavy traffic, with or w/o A/C on

My 1999 Jeep Grand Cherokee is having overheating problems, usually only if I am in heavy traffic. When travelling on the freeway, it's fine even with the A/C on. I replaced the thermostat about two months ago, so I'm wondering now if it could be something with the water pump.....

Any advice is appreciated

roxygirl25 is offline   Reply With Quote Quick reply to this message
Unread 07-20-2009, 04:52 PM   #2
SnowLeopard
Registered User
1997 ZJ 
 
Join Date: Apr 2009
Location: Texas
Posts: 4,456
You're going to have to provide more specifics on your Jeep in order for anyone to help you.
__________________
Yes, it snows in Texas.

"Roads? Where we're going we don't need roads"
SnowLeopard is offline   Reply With Quote Quick reply to this message
Unread 07-20-2009, 05:12 PM   #3
WhiteOut
Web Wheeler
 
WhiteOut's Avatar
1998 ZJ 
 
Join Date: Dec 2007
Posts: 8,192
Check to see if the rad is dirty, I had overheating issues and the lower rad was packed with mud and junk.
WhiteOut is online now   Reply With Quote Quick reply to this message
Unread 07-20-2009, 05:53 PM   #4
SaturnICL
Registered User
1999 WJ 
 
Join Date: Mar 2009
Location: Sparks,NV
Posts: 602
Wj's are notoriouse for the radiators going to crap.

First: drain coolant and look at it. is it dirty? oily? Green, yellow, red?

Second: remove rad hoses and flush the crap outof it from the top inlet.

Third: Boil a pot of water and lower t-stat into it to se if it opens up.

try that if it doesnt work replace radiator and i personaly if you are going to have the fron clip torn apart I would spend the $70 to buy and install a new water pump regardless of condition. (preventative medicine) Especialy for a 10 yr old rig.

Refill with yellow and or red coolant, never the green.

Good luck.
SaturnICL is offline   Reply With Quote Quick reply to this message
Unread 07-20-2009, 06:34 PM   #5
Jubei
Registered User
 
Join Date: Mar 2006
Posts: 47
Was it doing this before or after you changed the T-Stat? I've seen quite a few bad T-Stats right out the box.
Jubei is offline   Reply With Quote Quick reply to this message
Unread 07-20-2009, 08:07 PM   #6
MEinSoCal
Registered User
2001 WJ 
 
Join Date: Sep 2007
Location: Los Angeles, CA
Posts: 1,423
BTDT... i'm 99% sure you need a new electric fan.
__________________
Are you in SoCal? CLICK HERE!!
MEinSoCal is offline   Reply With Quote Quick reply to this message
Unread 07-20-2009, 08:18 PM   #7
BluThunder
Registered User
1997 TJ Wrangler 
 
Join Date: Feb 2009
Location: Binbrook
Posts: 33
x2 on the fan
BluThunder is offline   Reply With Quote Quick reply to this message
Unread 07-20-2009, 08:42 PM   #8
iluvtruenos
Registered User
2000 WJ 
 
Join Date: Dec 2006
Location: Chicago
Posts: 1,345
Get a mechanical fan, the V8's and I6's are the same, just make sure the **** doesn't hit the fan.

It sprays on the underside of the hood quite nicely.
__________________
My Jeep is a chick magnet with reverse polarity.

Rampant Pack of Retards group president.
2000 WJ, 4.5l, AX15, 242 D60/14b, 5.5" lift front, 7.5" rear. Ford Expedition rear coils, Ram 350 shocks, JKS, IRO Long Arms, cool Badlands flag thingy.
1987 XJ - Gone but not forgotten
iluvtruenos is offline   Reply With Quote Quick reply to this message
Unread 07-20-2009, 10:43 PM   #9
SnowLeopard
Registered User
1997 ZJ 
 
Join Date: Apr 2009
Location: Texas
Posts: 4,456
Quote:
Originally Posted by SaturnICL View Post
Wj's are notoriouse for the radiators going to crap.

First: drain coolant and look at it. is it dirty? oily? Green, yellow, red?

Second: remove rad hoses and flush the crap outof it from the top inlet.

Third: Boil a pot of water and lower t-stat into it to se if it opens up.

try that if it doesnt work replace radiator and i personaly if you are going to have the fron clip torn apart I would spend the $70 to buy and install a new water pump regardless of condition. (preventative medicine) Especialy for a 10 yr old rig.

Refill with yellow and or red coolant, never the green.

Good luck.
Why not the green? I guess it's too old school. It's what my ZJ has, but then it's from 97. I think it's been changed, as the coolant is clean, but it is green.
__________________
Yes, it snows in Texas.

"Roads? Where we're going we don't need roads"
SnowLeopard is offline   Reply With Quote Quick reply to this message
Unread 07-21-2009, 12:40 AM   #10
MEinSoCal
Registered User
2001 WJ 
 
Join Date: Sep 2007
Location: Los Angeles, CA
Posts: 1,423
Quote:
Originally Posted by SaturnICL View Post
Wj's are notoriouse for the radiators going to crap.

First: drain coolant and look at it. is it dirty? oily? Green, yellow, red?

Second: remove rad hoses and flush the crap outof it from the top inlet.

Third: Boil a pot of water and lower t-stat into it to se if it opens up.

try that if it doesnt work replace radiator and i personaly if you are going to have the fron clip torn apart I would spend the $70 to buy and install a new water pump regardless of condition. (preventative medicine) Especialy for a 10 yr old rig.

Refill with yellow and or red coolant, never the green.

Good luck.
the only time i worry about radiator problems is when it leaks. other than that, based on what the OP described with the overheating associated to the car not being in movement, it should be a bad fan. basically the fan is not able to keep up to proper speeds when still, but only turns normally because air is being rushed into the engine
__________________
Are you in SoCal? CLICK HERE!!
MEinSoCal is offline   Reply With Quote Quick reply to this message
Unread 07-21-2009, 08:40 AM   #11
Double E
2000 Laredo V8
 
Double E's Avatar
2000 WJ 
 
Join Date: Oct 2003
Location: Raleigh, NC
Posts: 3,684
What engine are we talking about here Roxy?

Miles?

Who did the most recent service to the t-stat?

No more replies till you give good info...
__________________
2000 Laredo 4.7L Selec-Trac. 177K miles, Leather, 245 tires, tow package, crappy CD changer, full size spare, roof cross-rails & sunroof.
Changes & fixes: Rear Addco sway bar & greasble bushings, upgraded headlights, upgraded tail lights, new hood struts (replaced 2X), new rear hatchglass struts, new radiator (replaced 3X), new oil pressure sending unit (replaced 4X), 2 new speed sensors, 2 new door lock actuators, new ignition key cylinder, chrome front tow hooks, Mobil 1 Synthetic 5/30, Purolator Pure One oil filter, EBC slotted & dimpled rotors, EBC Greenstuff pads, new front shocks (replaced 3X), new rear shocks (replaced 2X), new IRO steering stabilizer, new timing chain cover, new water pump, thermostat, new thermostat housing, new high pressure power steering hose, Michelin-X radials, new sunroof assembly, new single-piece lug nuts, new exhaust manifold studs & gasket on driver's side, new Durango alternator. Jeepforum.com sticker, Visit cobaltboatsforum.com when you can!
Double E is offline   Reply With Quote Quick reply to this message
Unread 07-21-2009, 10:49 AM   #12
SaturnICL
Registered User
1999 WJ 
 
Join Date: Mar 2009
Location: Sparks,NV
Posts: 602
Quote:
Originally Posted by SnowLeopard View Post
Why not the green? I guess it's too old school. It's what my ZJ has, but then it's from 97. I think it's been changed, as the coolant is clean, but it is green.
The green will eat the impellar in the waterpump over time.

Good source of info on your jeep!
http://www.wjjeeps.com/service/cooling.htm


COOLANT TYPES
There are essentially three basic types of antifreeze:

Traditional North American GREEN antifreeze, the original universal formula that everybody used until the introduction of today is extended-life coolants. The fast-acting silicate and phosphate corrosion inhibitors provide quick protection for bare iron and aluminum surfaces, and have a proven track record of providing trouble-free service in virtually any vehicle application (domestic, Asian or European), assuming the chemistry is correct. For example, OAT coolants should not be used in a vehicle that specifies the use of a hybrid OAT coolant. Again, always defer to the owners manual. But the short-lived nature of the corrosion inhibitors means this type of coolant should be changed every two to three years or 30,000 miles (though some products now claim a service interval of up to 50,000 miles with improved chemistry).

OAT-based extended-life coolants. OAT stands for Organic Acid Technology, and includes such ingredients as sebacate, 2-ethylhexanoic acid (2-EHA) and other organic acids, but no silicates or phosphates (except in the case of Toyota's pink extended-life coolant, which adds a dose of phosphate to its extended-life OAT-based antifreeze). OAT-based coolants are usually (but not always) dyed a different color to distinguish them from traditional North American green antifreeze. GM OAT-based Dex-Cool is orange. Volkswagen/Audi uses a similar product that is dyed pink. But Honda has an extended-life OAT coolant that is dyed dark green and does not contain 2-EHA.

The corrosion inhibitors in OAT coolants are slower acting but much longer-lived than those in traditional North American green coolants. Consequently, OAT coolants typically have a recommended service life of five years or 150,000 miles.

OAT corrosion inhibitors provide excellent long-term protection for aluminum and cast iron, but may not be the best choice for older cooling systems that have copper/brass radiators and heater cores. It depends on the formula.
SaturnICL is offline   Reply With Quote Quick reply to this message
Unread 07-21-2009, 10:55 AM   #13
SnowLeopard
Registered User
1997 ZJ 
 
Join Date: Apr 2009
Location: Texas
Posts: 4,456
Quote:
Originally Posted by SaturnICL View Post
The green will eat the impellar in the waterpump over time.

Good source of info on your jeep!
http://www.wjjeeps.com/service/cooling.htm
I've got a ZJ though, and I'm pretty sure it's always had the green stuff in it. That'd be 13 years or there around now. Why does the green eat the impeller, and why would design the waterpump in such a way that the coolant would damage it? It makes no sense, but then engineers don't often seem to make common sense decisions. I wonder how many ZJ owners run anything but the ol' green.
__________________
Yes, it snows in Texas.

"Roads? Where we're going we don't need roads"
SnowLeopard is offline   Reply With Quote Quick reply to this message
Unread 07-21-2009, 11:34 AM   #14
TJsZJ
Registered User
1995 ZJ 
 
Join Date: Jun 2009
Location: Omaha,NE
Posts: 47
I run the green 50/50 mix in mine as well. Thats what most older cars are made to run off of. They didnt change to the newer orange stuff until right around '99 or 2000. If there is ever any doubt which to use, look at your owner's manual.
TJsZJ is offline   Reply With Quote Quick reply to this message
Unread 07-21-2009, 11:36 AM   #15
311LJ
311Popo
 
311LJ's Avatar
2004 LJ Wrangler 
 
Join Date: Sep 2008
Location: Springville, Utah
Posts: 7,446
If you have the hydrolic fan you should check your power steering fluid and pump. If you low on that, then the fan won't work. since it feeds off the power steering system for its power / hydrolic needs
__________________
John
04 TJ Unlimited, GenRight Armor, 37's Unlimited Build Thread
89 XJ Laredo, 31's
07 WK Overland, Hemi, Chrome bug deflector
[SOLD] Jimmer 01 WJ *2009 GCOTY* WJ Build Thread
*UTAH JEEPCREW #01*

Quote:
Originally Posted by Tuffjeeper View Post
I ♡ John
311LJ is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

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:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

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.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.