# 99 grand cherokee overheating...



## bravesjtd (Dec 1, 2011)

My 99 Grand Cherokee is overheating. It is the 4.0 V6 4x4 Laredo model. The temp gauge rises way past the normal 210. I have changed the thermostat and it is still happening. I hear a bubbling sound coming from the upper hose/t-stat housing area when it is hot. The heat is ice cold when I turn it on also. There are a few drops of antifreeze dripping from somewhere, I think from the bottom of the coolant resevoir. Does anyone know how I could test the fan relay? This engine only has the one fan by the radiator, not 2 fans. This fan does turn. Any help would be greatly appreciated. Thank you...


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## Basementgeek (Feb 7, 2005)

Hi and welcome to TSF

Are you saying that the fan never comes on ? The bubbling sound may be air in the system.

BG


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## bravesjtd (Dec 1, 2011)

The fan is turning but it stays on and it doesn't seem like it picks up speed when the engine gets hot. I'm going to change the fan relay today and see if that solves it.... Thank you...


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## SABL (Jul 4, 2008)

I'm seeing the V-6 as a 2.8L....the 4.0L is an inline 6cyl and there may be a big difference when it comes to this problem. 

Pressure test the cooling system and look for leaks. If the coolant in the reservoir is bubbling or churning......not good.


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## wolfen1086 (Oct 4, 2007)

If the engine is a V in a Grand Cherokee it should be one of the following: 4.0 L (242 CID) - 4.7 L (287 CID) - 4.7 L (287 CID) - 3.1 L Diesel - 2.7 L Diesel.
And an electric fan COULD also be the motor on its way out


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## kjms1 (Jun 4, 2010)

> The heat is ice cold when I turn it on also


doesnt 1 of the heater hoses hook right to the water pump ???? 


i would look at the water pump not pumping or the radiator stopped up ... when it gets hot FEEL around the top of the rad and the bottom, should be a small dif in the two .... feel the heater hoses both cold or just 1 ... is the bottom rad hose sucked together

with the fan working and the thermostat changed that leave Radiator, water pump, head gasket problem, or air in the system


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## wolfen1086 (Oct 4, 2007)

kjms1 said:


> doesnt 1 of the heater hoses hook right to the water pump ????
> 
> 
> i would look at the water pump not pumping or the radiator stopped up ... when it gets hot FEEL around the top of the rad and the bottom, should be a small dif in the two .... feel the heater hoses both cold or just 1 ... is the bottom rad hose sucked together
> ...



A hose connecting to the water pump all depends on the engine, some do some don't, but I'm with you on this one, I too would start checking the water pump along with the fan motor


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## bravesjtd (Dec 1, 2011)

Thank you for your replies. I have changed the fan relay and the electric fan. The fan comes on when the temp reaches around 210 but it is still overheating. I removed the t-stat to see if maybe I had gotten a bad one but it is still the same. The lower radiator hose is not getting warm at all. The upper hose is boiling hot. The radiator was installed brand new in April. ?????


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## Basementgeek (Feb 7, 2005)

I too think possible water pump.

BG


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## SABL (Jul 4, 2008)

Basementgeek said:


> I too think possible water pump.
> 
> BG


I have seen the impeller vanes completely erode away on some water pumps....better check the pump.


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## wolfen1086 (Oct 4, 2007)

I've never seen one completely eroded away, but I HAVE seen them break loose from the pulley a d the pulley spin but not the impeller


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## kjms1 (Jun 4, 2010)

bravesjtd when you say the rad is new do you mean new new or a used one that is new to your car

but if you got the thermostat out and the lower hose is staying cold, water is not moving thru the rad ... which if the pump is working it will circulate all the time provided the rad is not stopped up or lower hose to soft that it collapse 

some water pumps you can remove the lower hose from it and with a mirror look up in the pump and turn the pulley and see if is turning or with a screwdriver see if you can move the impellers and hold the pulley

plus make sure all air is bleed out of system using the air bleed screw


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