Overheating issues

Asked by May 18, 2017 at 06:02 PM about the 1999 Jeep Grand Cherokee Laredo 4WD

Question type: Maintenance & Repair

I have a 99 grand Cherokee Laredo and I'm
at my wits end with overheating issues
jeep runs great on the highway but as soon
as I hit traffic it starts to over heat as soon
as traffic lets up and I start moving again
temp goes back down I have already
replaced the thermostat and water pump
flushed radiator it's self and threw engine
block and still the same problems I pulled
the thermostat out and ran it it's fine until I
hit traffic and temp starts to rise again I'm
at my wits end with this issue help please I
read the overheating issues posted by
others and I have done most of what they
said already

8 Answers


Flushing a radiator may not always clear the passages. Radiators are known to burn engines and transmissions, so if it's suspect, update it. It sounds like a small head gasket leak could do it also. Buy a kit from any parts store that sits on top of the coolant reservoir and had a liquid that changes colors if combustion gasses are present in the cooling system.

I have already changed the fan last year cause it burnt out and replaced the radiator 2 years ago what is the name of the kit you are talking about


Head gasket test kit


Block tester kit


Brian is correct. But also note: the forward movement of the vehicle is cooling the engine/radiator because the fan isn't. That means the fan is not running for whatever reason. That could be a bad fan or a bad fan control switch. Open the hood with motor running. When the temperature guage says 210 degrees F, the fan should be running. Listen and look with a flashlight. Don't touch blades.

1 of 1 people found this helpful.

my 99 is doing the same thing. and i have replaced the fan,radiator, water pump, temp sensor and thermostat, coolant ,hoses ,head gasket and other things. plus, when mine over heats,the ac stops blowing cold. i just now posted a question looking for help. good luck dude!

1 of 1 people found this helpful.

this is my question https://www.cargurus.com/Cars/Discussion-t15886_ds805557

Ok gear heads found out that my fan was running in the wrong direction didn't do the block test cause there wasn't a need for it the easy way to test if the fan is running in the right direction is while car is at temp at 210 take a paper towel and put it right in front of the grill where the radiator is if the paper towel gets sucked in fan is running correctly if it's gets blown away fans running in wrong direction easy fix is switch the to wires around and that fixed my issue a week later I blew the lower hose from water pump to radiator that was a fun fix lol now I'm having a check engine light issue check engine light comes on flashes and goes off and it does it basically when it wants to but this time it stayed on and got multiple misfire codes so I changed coilpack plugs all to mopar specs and reset codes ran for 50miles and still getting the same thing but this time misfire and say I have a bad camshaft sensor so changed plugs and sensor and I'm still getting these codes could I be having a electric shirt some where

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