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-   -   99 Grand Cherokee overheating when in heavy traffic, with or w/o A/C on (http://www.jeepforum.com/forum/f13/99-grand-cherokee-overheating-when-heavy-traffic-w-o-c-820802/)

roxygirl25 07-20-2009 03:39 PM

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 :)

SnowLeopard 07-20-2009 03:52 PM

You're going to have to provide more specifics on your Jeep in order for anyone to help you.

WhiteOut 07-20-2009 04:12 PM

Check to see if the rad is dirty, I had overheating issues and the lower rad was packed with mud and junk.

SaturnICL 07-20-2009 04:53 PM

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.

Jubei 07-20-2009 05:34 PM

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.

MEinSoCal 07-20-2009 07:07 PM

BTDT... i'm 99% sure you need a new electric fan.

BluThunder 07-20-2009 07:18 PM

x2 on the fan

iluvtruenos 07-20-2009 07:42 PM

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.

SnowLeopard 07-20-2009 09:43 PM

Quote:

Originally Posted by SaturnICL (Post 7614588)
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.

MEinSoCal 07-20-2009 11:40 PM

Quote:

Originally Posted by SaturnICL (Post 7614588)
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

Double E 07-21-2009 07:40 AM

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...

SaturnICL 07-21-2009 09:49 AM

Quote:

Originally Posted by SnowLeopard (Post 7616726)
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.

SnowLeopard 07-21-2009 09:55 AM

Quote:

Originally Posted by SaturnICL (Post 7618992)
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.

TJsZJ 07-21-2009 10:34 AM

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.

311LJ 07-21-2009 10:36 AM

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


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