Have Jeep questions? Ask a Jeep repair expert for answers

Ask an Expert, Get an Answer ASAP!

Jeep Thermostat Problems

A thermostat is a device installed in your Jeep that monitors and controls the flow of coolant to the engine. The Jeep thermostat is either located on the top of the engine in the outlet leading to the radiator or at the bottom of the engine near the hose inlet. The thermostat is one of the main components of your Jeep’s cooling system. If you are having Jeep thermostat problems you should seek professional assistance. Read below where Experts have answered questions on Jeep thermostat repair, installation and replacement.

What is causing my Jeep thermostat to overheat?

You need to bleed the coolant whenever you open the system. If you don’t bleed the system after replacing the thermostat it could cause the thermostat to overheat. The jiggle pin in the thermostat has to be at 12:00. If it is not at 12:00 then air gets trapped in the system and the thermostat will not open. If there is no air trapped then when it is cold you need to remove the radiator cap and make sure the coolant is almost full and start the engine. You need to let the engine run till it warms up and the thermostat stays fully open. Top it off before you put the radiator cap on. As it warms the air will come out and the coolant level will keep fluctuating. When the thermostat opens it will drop and you will have to top it off. Be careful while performing these steps, as the coolant and steam are very hot.

If the thermostat runs at normal temperature on the highway and you are not able to hear the electric fan come on there may be a bad fan relay or bad fan.

If you have jumper wires you can unplug the fan connector and jump the fan to see if it works. If the fan does not come on or it runs slowly there could be a bad motor present and you will need to replace the fan assembly. A bad fan motor will burn up the relay. If the fan motor is drawing up too much of current, it will overload the relay and burn it up. If the fan runs and the fuse is good there may be a problem with the fan relay.

How to replace the thermostat in a 1999 Jeep Grand Cherokee?

The thermostat is located where the lower hose connects to the engine. You will need to take the belt off a couple of pulleys for easy access. Drain out the coolant from the bottom of the radiator. To remove the thermostat you need to first disconnect the negative battery cable at the battery. Then drain the cooling system until the coolant level is below the thermostat. Remove the accessory drive belt. You then need to remove the lower radiator hose clamp and lower radiator hose at the thermostat housing. Proceed to remove the thermostat housing mounting bolts, thermostat housing and the thermostat.

Why does my 2008 Jeep Commander heater take a long time to turn on and how do I get it to heat up quickly?

In most cases if the heater core is restricted it takes longer for the heater to warm up. You will need to flush the heater core and see if it is dirty. You should also check the temperature sensor to make sure that it is working properly and all connections are good.

You can flush out the coolant system, especially the heater core and add some antifreeze. Don’t add too much water in the system. A higher volume of water will take a longer time to heat. You can also try installing a heater block in the engine. The heater block keeps the coolant warm inside the engine block. The heater will also come on faster as the coolant is warm.

The most common signs of a faulty Jeep thermostat are poor fuel efficiency, overheating, and low heater output. Failure to detect and fix Jeep thermostat problems can cause severe damage to the engine. To learn how to diagnose and repair problems with your Jeep thermostat you should contact an Expert.
Please type your question in the field below

3 verified Jeep Mechanics are online now

Jeep Mechanics on JustAnswer are verified through an extensive 8-step process including screening of licenses, certifications, education and/or employment. Learn more


Shop Foreman

3723 positive reviews

22 Year Factory trained technician

Vocational, Technical or Trade Scho

2668 positive reviews

ASE Certified Technician

Vocational, Technical or Trade Scho

1130 positive reviews
See all Jeep Mechanics
JustAnswer in the news:
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
Web sites like
...leave nothing to chance.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.