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jazzmaster, ASE Certified Tech
Category: Jeep
Satisfied Customers: 2951
Experience:  ase certified--32 yrs experience
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Wrangler: why is my 2000 jeep 4 liter wrangler overheating

Customer Question

why is my 2000 jeep 4 liter wrangler overheating ? I changed thermostat and raised front off the ground to remove air pockets
Submitted: 2 years ago.
Category: Jeep
Expert:  jazzmaster replied 2 years ago.
did you have an over heating problem before changing the thermostat ?
Customer: replied 2 years ago.
I just bought it, and noticed when I went to change it, there was a new one in it. So I will say yes. I Have not done anything to the radiator. Looks good down inside with the naked eye
Expert:  jazzmaster replied 2 years ago.
ok, here is what I would do.
make sure the level is up in the radiator
start it and run it around 10 minutes with the cap on.
Then shut it off and wait about 10 minutes
when you feel no pressure in the upper hose remove the cap and let the level drop a bit if it already hasn't .
Ad coolant and repeat the procedure until the level doesn't drop anymore . then put the cap on and run it (watching the gauge)
this method is the best way to get any air out .'
if it doesn't over heat after doing tis then good and take it for a short drive to be sure .
if it is still getting hot ,then when it's cooled down take off the cap and start it.
look at/in the rad cap hole and see if you see a lot of air bubbles in the coolant or if the coolant is starting to come out the rad fill
if it is then shut it off (cap it first)
You will need at this point to rent a block test kit at a parts store -you will have to buy the fluid that this tester needs -
the bottles costs around 7 or 8 dollars .
follow the instructions .
what you are doing is checking for hydro carbons(exhaust gases) in the cooling system with this tool.
if the blue liquid turns color then there is either a problem with a head gasket/cracked head or even cracked block in rare cases.
I forgot to mention .is the cooling fan working ?
Customer: replied 2 years ago.
The cooling fan is not electric, how can I tell if it has any problems. Could the radiator be plugged.It usually takes about 5 miles for it to get hot. When I was adding coolant I had the cap on and off and did not notice any little bubbles after it burped the bigger air out
Expert:  jazzmaster replied 2 years ago.
can you see the coolant flowing in the radiator after the thermostat opens ?
is the bottom rad hose cold while the top one is hot ?
Customer: replied 2 years ago.
The fan is on a clutch , the level in the radiator dropped when the thermostat opened. Is there any way to tell if the fan is bad, it does not wiggle when I shake it.
Expert:  jazzmaster replied 2 years ago.
Excessive Free-Wheeling when spun manually (when engine is stopped) - With the engine stopped, manually spin the fan. If the Fan spins excessively, over 3 revolutions, as though there is no resistance it should be replaced.
I dont think that will cause your motor to over heat after driving 5 miles ,I would do the cooling system air bleed as I stated and then if it still over heats then do a block test on the cooling system ...jazzmaster ..