There room a couple of reasons why her Jeep grand Cherokee would certainly be overheating when idling. The most common ones incorporate a negative thermostat, water pump, electrical fans, and also low coolant level. This overview is intended to help you uncover the cause of this overheating in the most efficient method possible. So, let’s begin with what’s easy and take that from there.

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If your grand Cherokee is running and also driving fine, but you finish up stopped somewhere and it begins overheating as soon as idling, this guide is for you. If it’s overheating at all engine speeds, check outJeep grand Cherokee Overheating.


Make sure to inspect and also work ~ above the engine when it is cold. Electrical fans can kick top top at any time.

Grand Cherokee: Overheating as soon as Idling Causes and Solutions

1. Low Coolant

While that seems respond to intuitive, when your grand Cherokee is short on coolant might run ok v wind hitting the radiator, but when idling there’s simply not sufficient coolant to correctly cool the engine.

Solution: to fill the radiator and also coolant reservoir earlier up. Never ever do this once the engine is warm. The cold engine coolant have the right to “shock” the block and cause a cracked or also a frozen plug come drop out.

Filling it ago up is no the fix. The coolant had actually to leak indigenous somewhere. Look under the automobile when it is parked and see if you can see pool of coolant. If over there are, begin directly above those puddles in your search.


A coolant leak is usually brought about by:

Cracked Hoses– There room two hoses the come and also go to your grand Cherokee’s radiator. One sends out the hot coolant earlier from the engine come the radiator to it is in cooled. And also the various other one sends the coolant back to the water pump come cool the engine. This hoses deserve to crack with age. Take it a look in ~ them and also see if they have actually been leaking. Even if they are dry, they should still have a chalky look to them where they have been leaking coolant (it’s mineral deposits).

2. Poor Electric Fan


If the coolant level appears to it is in fine, then the following easiest point to look in ~ is the fan. Many vehicles use electric fans to cool the radiator as soon as it gets warm enough. This fans space most crucial when the auto is idling. These fans can and do fail.

Solution: v the engine hot and also idling (but no yet overheating) pop the hood open and see if the pan is turning. If it is not turning at every you understand you have a bad fan.

Check the fuse and fan relay to check out if lock are acquiring power. If castle are, you’ll need to replace the fan. Here’s a an excellent guide to troubleshooting a radiator fan.

3. Negative Thermostat

Next on the list is the thermostat. Your grand Cherokee’s thermostat controls as soon as coolant does and doesn’t get in the engine. It’ll either be ~ above the block or water pump.

Solution: It can be hard to tell if a thermostat is bad without simply replacing it. Does the auto get hot within a couple of minutes of control (and the coolant is full)? That can be sufficient to tell the the thermostat isn’t opening all the way. It typically takes an engine a while come overheat when it is complete of coolant.

You’ll have to replace it, which is around a 2/10 in mechanically difficulty. Most likely you’ll simply need a ratchet, extension, and 10mm socket.

Here’s more on this: Jeep cool Cherokee: poor Thermostat Diagnosis

4. Bad Water Pump


The water pump in your vehicle is turn by the grand Cherokee’s engine accessory journey system. Together the engine rpm increases, so does the rate of the water pump. When the automobile is idle, the water pump is turning slowly.

Solution: A negative water pump isn’t efficient. Once the vehicle is overheating when idling the water pump is not able to move the coolant through the radiator and earlier to the engine. You can test this by placing the auto in neutral or park and also revving the engine to around 1000 RPM under the redline for a couple of seconds. You must see the temperature dip as the water pump spools up.

Replacing a water pump is only as complicated as acquiring to it. Which, depending on it’s location, can be fairly easy or a full nightmare.

Here’s much more on diagnosing a negative water pump.

Honorable Mention: Temp Gauge

While your grand Cherokee’s temperature gauge is typically pretty reliable, the still is an electrical an equipment that have the right to fail. A mechanic would inspect the temperature that the engine manually v a warm gun in order come ensure the the gauge was reading correctly prior to tackling the repair.

When the auto is overheating when idling and you smell the smells linked with a temp the is also high, you have the right to throw the temp gauge theory out.

See more: Where Is Paris In France And How Far Is Paris From The Ocean ?


Conclusion: Jeep cool Cherokee Overheating once Idling

Hopefully, this guide to why your cool Cherokee may be overheating as soon as idle helped you settle your vehicle. If over there is anything that you would like to add that could help the next human being with theirs, your comment below is most welcome.