After countless attempts to help disseminate the correct way to troubleshoot overheating issues i've finally decided to write an article about it.
Note: if nothing on this list fixes your overheating problem, sell your car. It's possessed and only god can help it now.
So you're overheating. Maybe it's only when you turn your A/C on. Maybe it's only when sitting in traffic. Did you install a FMIC and all of a sudden your car is sweltering?
Read through the list. Of course not everything may apply to you, so address the issue accordingly.
Replace your thermostat. Try a 180° F Mitsubishi thermostat. It is part number MD997607.
Your radiator cap might be old, and leaking too easily. Try a 16 lb radiator cap from a Nissan 300Z TT. Watch out - you might blow old heater or coolant hoses with the higher pressure, so be careful, or replace your hoses beforehand.
Your fans might not be running. Replace the fan temperature switch at the bottom of the radiator.
Low coolant levels. Top up your overflow bottle. There should always be coolant in the bottle. If your system is perpetually low on coolant, your bottle isn't big enough.
Your overflow bottle is not allowing coolant back in. Check the overflow bottle still has a
hose leading to the bottom of the bottle. The system must be able to draw coolant back in.
Flush your radiator. Old coolant (or a clogged radiator) could be the problem.
Try adding some Water Wetter or RMI-25 to aid cooling. Note that some of these products promote corrosion to a small degree.
Try a 90/10 to 70/30 water/antifreeze mix. More water leads to more cooling, but easier freezing and more corrosion.
Try running with no thermostat. If you still overheat, the problem is probably not in your cooling system per se; probably your difficulty is airflow through the radiator. (TEMPORARY TROUBLESHOOTING TECHNIQUE. Do not keep the thermostat out of the car to fix your problem...)
Wire both fans to run simultaneously. Obviously this only works if you have an secondary (air conditioning) fan to hotwire.
Run both fans permanently. That is, wire them to be always on. Note that the driver's side of the radiator probably doesn't cool as much as passenger side, because of where the radiator inlet and outlet are placed.
Remove the rear hood weatherstripping. Or, shim the rear hood hinges to raise the rear hood edge about 1/4-1/2". This promotes airflow out of the engine bay.
Install better fans. There are "high-performance" models available - get the ones with the best airflow.
Try shrouded fans instead of unshrouded fans. Shrouded fans seem to cool better.
Install some ducting to force incoming air into radiator. This mostly works only if you are having problems only when driving at highway speeds.
Install some high-temperature weatherstripping on top of radiator to try and force more air through it.
Open up front bumper fascia to allow more air flow to radiator.
Replace or upgrade the radiator. Fluidyne and Arizona Performance make upgrade models. You can try to get your radiator cleaned (or "rodded out") if you want to.
Install an external oil cooler to try and lose some heat that way. Leave a gap between the oil cooler and the radiator, if possible.
Wrap the water pipe near the turbo with heat wrap or jet hot/ceramic coat it.
If you have the air conditioning still in, remove the A/C condensor.
Maybe the water pump belt is slipping.
Install a new water pump.
Check your crankshaft pulley has not separated.
Check that your A/C refrigerant level is correct. Only applies if the A/C causes the overheating.
If all else fails, maybe a leaking headgasket is the problem. Run a compression test. Don't forget about the torque specs for the head bolts/studs also. Sometimes a simple torque wrench can fix your problem.
Special thanks to www.vfaq.com
Note: if nothing on this list fixes your overheating problem, sell your car. It's possessed and only god can help it now.
So you're overheating. Maybe it's only when you turn your A/C on. Maybe it's only when sitting in traffic. Did you install a FMIC and all of a sudden your car is sweltering?
Read through the list. Of course not everything may apply to you, so address the issue accordingly.
Replace your thermostat. Try a 180° F Mitsubishi thermostat. It is part number MD997607.
Your radiator cap might be old, and leaking too easily. Try a 16 lb radiator cap from a Nissan 300Z TT. Watch out - you might blow old heater or coolant hoses with the higher pressure, so be careful, or replace your hoses beforehand.
Your fans might not be running. Replace the fan temperature switch at the bottom of the radiator.
Low coolant levels. Top up your overflow bottle. There should always be coolant in the bottle. If your system is perpetually low on coolant, your bottle isn't big enough.
Your overflow bottle is not allowing coolant back in. Check the overflow bottle still has a
hose leading to the bottom of the bottle. The system must be able to draw coolant back in.
Flush your radiator. Old coolant (or a clogged radiator) could be the problem.
Try adding some Water Wetter or RMI-25 to aid cooling. Note that some of these products promote corrosion to a small degree.
Try a 90/10 to 70/30 water/antifreeze mix. More water leads to more cooling, but easier freezing and more corrosion.
Try running with no thermostat. If you still overheat, the problem is probably not in your cooling system per se; probably your difficulty is airflow through the radiator. (TEMPORARY TROUBLESHOOTING TECHNIQUE. Do not keep the thermostat out of the car to fix your problem...)
Wire both fans to run simultaneously. Obviously this only works if you have an secondary (air conditioning) fan to hotwire.
Run both fans permanently. That is, wire them to be always on. Note that the driver's side of the radiator probably doesn't cool as much as passenger side, because of where the radiator inlet and outlet are placed.
Remove the rear hood weatherstripping. Or, shim the rear hood hinges to raise the rear hood edge about 1/4-1/2". This promotes airflow out of the engine bay.
Install better fans. There are "high-performance" models available - get the ones with the best airflow.
Try shrouded fans instead of unshrouded fans. Shrouded fans seem to cool better.
Install some ducting to force incoming air into radiator. This mostly works only if you are having problems only when driving at highway speeds.
Install some high-temperature weatherstripping on top of radiator to try and force more air through it.
Open up front bumper fascia to allow more air flow to radiator.
Replace or upgrade the radiator. Fluidyne and Arizona Performance make upgrade models. You can try to get your radiator cleaned (or "rodded out") if you want to.
Install an external oil cooler to try and lose some heat that way. Leave a gap between the oil cooler and the radiator, if possible.
Wrap the water pipe near the turbo with heat wrap or jet hot/ceramic coat it.
If you have the air conditioning still in, remove the A/C condensor.
Maybe the water pump belt is slipping.
Install a new water pump.
Check your crankshaft pulley has not separated.
Check that your A/C refrigerant level is correct. Only applies if the A/C causes the overheating.
If all else fails, maybe a leaking headgasket is the problem. Run a compression test. Don't forget about the torque specs for the head bolts/studs also. Sometimes a simple torque wrench can fix your problem.
Special thanks to www.vfaq.com
