My 89 YJ still overheating and I have invested thousands of dollars trying to address the issue over the last few years.
Replaced the radiator with an all aluminum high performance radiator twice (2 different brands)
Replaced thermostat at least 5 times with everything from 160 degree too 190 degree and even tried leaving it out.
Had head checked for cracks and rebuilt.
Replaced head gasket making extra effort to insure correct orientation of the new gasket.
Replaced fan clutch with correct rotation clutch.
Replaced water pump twice with correct rotation pump.
Tried two different high output electric fans and fan shrouds.
Removed the freeze plugs and pressure washed inside the water jackets on the block.
Replaced all hoses (upper and lower radiator and heater) twice.
Replaced the distributor three times.
Replaced the carburetor twice including completely rebuilding the original 2bbl Carter/Weber 2 times before opting for a Motorcraft 2105.
Flushed entire cooling system with a chemical flush twice and also had a shop use a cooling system flush machine flush the cooling system as well.
Added a high efficiency coolant additive to the manufacture recommended coolant mixture.
Checked that the correct factory OEM radiator fan was being used.
Replaced the serpentine belt three times.
Replaced the harmonic balancer thinking that the outer ring with the timing marks may have slipped slightly causing a slight difference in the accuracy of the timing.
I raised the rear of the hood to allow the engine compartment to vent heat thinking that the heat was not able to escape.
Replaced the temperature sending unit.
Replaced the entire exhaust system from the exhaust manifold to the tailpipe (including the catalytic converter) thinking there was a little restriction.
I did install an a/c (the dealer installed type used in 89) and put an electric fan in front of the condenser (didn’t have that addition in 89).
The overheating issue occurs when the outside temperature is above 60 degrees and ether at idle or driving below 20 mph for around ten minutes (quicker with a/c is on) or when pushing it up above 60 mph especially on inclines (again worse when running the a/c).
If I run the heater it helps bring the temperature down where it stabilizes to around 240 degrees and as low as 220 degrees if it turn off the a/c (when it is 110 degrees outside running the heater becomes unbearable inside the cabin.
If I spray water through the grill the temperature drops to 210 degrees and stays there even when it’s 110 degrees outside and the a/c is on high.
WHAT AM I MISSING???
PLEASE HELP if you know of a fix!
Replaced the radiator with an all aluminum high performance radiator twice (2 different brands)
Replaced thermostat at least 5 times with everything from 160 degree too 190 degree and even tried leaving it out.
Had head checked for cracks and rebuilt.
Replaced head gasket making extra effort to insure correct orientation of the new gasket.
Replaced fan clutch with correct rotation clutch.
Replaced water pump twice with correct rotation pump.
Tried two different high output electric fans and fan shrouds.
Removed the freeze plugs and pressure washed inside the water jackets on the block.
Replaced all hoses (upper and lower radiator and heater) twice.
Replaced the distributor three times.
Replaced the carburetor twice including completely rebuilding the original 2bbl Carter/Weber 2 times before opting for a Motorcraft 2105.
Flushed entire cooling system with a chemical flush twice and also had a shop use a cooling system flush machine flush the cooling system as well.
Added a high efficiency coolant additive to the manufacture recommended coolant mixture.
Checked that the correct factory OEM radiator fan was being used.
Replaced the serpentine belt three times.
Replaced the harmonic balancer thinking that the outer ring with the timing marks may have slipped slightly causing a slight difference in the accuracy of the timing.
I raised the rear of the hood to allow the engine compartment to vent heat thinking that the heat was not able to escape.
Replaced the temperature sending unit.
Replaced the entire exhaust system from the exhaust manifold to the tailpipe (including the catalytic converter) thinking there was a little restriction.
I did install an a/c (the dealer installed type used in 89) and put an electric fan in front of the condenser (didn’t have that addition in 89).
The overheating issue occurs when the outside temperature is above 60 degrees and ether at idle or driving below 20 mph for around ten minutes (quicker with a/c is on) or when pushing it up above 60 mph especially on inclines (again worse when running the a/c).
If I run the heater it helps bring the temperature down where it stabilizes to around 240 degrees and as low as 220 degrees if it turn off the a/c (when it is 110 degrees outside running the heater becomes unbearable inside the cabin.
If I spray water through the grill the temperature drops to 210 degrees and stays there even when it’s 110 degrees outside and the a/c is on high.
WHAT AM I MISSING???
PLEASE HELP if you know of a fix!