Radiator fans not coming on

L

LucasJ

New Member
Hi,

I recently did a 4g15 - 4g93 swap in my 2000 ce lancer. Everything works fine except for the radiator fans, they don't seem to come on even when the car warms up, they only come on when I turn the A/C on.

I have bleed the coolant properly, I have replaced the coolant temp sensor, water pump and thermostat, if the fans themselves work when a/c is on it can't be a wiring issue (I don't think). I have also noticed my temp gauge sits at just below half which from what I've researched means its too cold for the fans to come on, but I've driven the car for over an hour in aussie summer heat and the gauge never goes above half.

I haven't had any overheating issues yet but I can tell pretty obviously the engine is very hot, and I can smell a bit of burnt coolant from the engine bay after a drive. Oh and no coolant leaks or anything like that either.

Any help would be hugely appreciated, sorry if this has been posted before, i couldn't find any posts about this specific issue. (I don't want to cook brand new engine :O)
 
Let the engine warm up idling till the temp gauge goes above half and see what happens. Do you have a good heater? It can take 10 or 15 minutes to get up to temp just idling and when driven above 40kmh the air passing through the radiator cools the engine. Fans don't really have much affect above that speed.
 
I've done that, let it idle for a while (20mins or so) and still nothing. Heater works fine sorta. I've noticed there isnt much coming out of the air vents inside the car even when blower is on max. So not sure if that affects it or not, I just assumed they might've got clogged.

And yeah like I said the temp gauge will not go above just below half no matter how long I idle it or drive it.
 
Drive it then up to temp turn heater off then let idle till it overheats or turns fans on. It will only run one fan and it will be fairly quiet.
 
Had the same problem on my Proton Wira long time ago;
4G15 uses a thermo switch on the radiator to turn the fans on (check on the small old radiator).
Most 4G93 turn the fans on from the ECU (sends ground to activate the fan relay in the engine bay), so I suspect that's your problem - check and report. How many yellow connectors do you have on your ECU - 3 or 4?
 
I have 4 yellow connectors on the ecu, is there a secondary relay I need that the 4g93 has but the 4g15 doesn't? I checked the fan relay in the fuse box and its fine.

Another thing, when I unplug the coolant temp sensor the fans come on. The car idles weird and the fans stay on forever so I'm not gonna leave it unplugged, so Im assuming the ecu has a fail safe mode if its not receiving a reading from the CTS and just automatically turns the fans on.
 
LucasJ. Did you use the 4g15 radiator or the 4g93 radiator? I am also having a similar issue not 100% sure that mines turning on either also just completed a 4g93 swap. Did you find a solution? ill test to see if my thermo fan kicks on today. On the other hand I havent had any issues with airflow from my vents. I haven't used my ac yet ( needs to be regassesd) but i have used the heat from the engine bay and haven't had any issues. I did also notice that the engine bay retains heat alot more now. could be due to thermo fan not turning on??
 
AC will trigger one fan to spin. Coolant temp above i think its 89* will trigger the other fan to spin until coolant is below 86*
 
donki said:
AC will trigger one fan to spin. Coolant temp above i think its 89* will trigger the other fan to spin until coolant is below 86*
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ill let it itdle for about 20 min and see what temp it will get to but everytime ive taken the car out since the swap I haven't had the thermo kick on. I know the fan on the drivers side is ac. I haven't had an issuse with the thermo fan not working that I am aware of. i don't belive the thermostat is faulty either because I had open when i brought the donor car home(from memory). any solutions to really get it up to temp to confirm?
 
Idle for 10mins then hold revs at 2-3k rpm for 30secs, rest for 10, repeat until hot. Or drive it for 5mins
 
Phez2000 said:
LucasJ. Did you use the 4g15 radiator or the 4g93 radiator? I am also having a similar issue not 100% sure that mines turning on either also just completed a 4g93 swap. Did you find a solution? ill test to see if my thermo fan kicks on today. On the other hand I havent had any issues with airflow from my vents. I haven't used my ac yet ( needs to be regassesd) but i have used the heat from the engine bay and haven't had any issues. I did also notice that the engine bay retains heat alot more now. could be due to thermo fan not turning on??
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Still using 4g15 radiator and fans. I haven’t had any issues with ac or heater. Engine bay is definitely hotter and retains that heat longer.

Until I figure out the problem, whether that’s putting in a 4g93 radiator and fan or whatever the fix is. I’ve just been turning the ac on when idling or in slow traffic, as that triggers both fans to come on. Whereas when driving above 30-40kph the air coming in is enough to keep the engine cool…ish

I’ve replaced thermostat, water temp gauge, coolant temp sensor, all ac/rad fan relays. The only thing not changed is the radiator and fans themselves. Could probably pick one up from a wreckers and swap them over and pray that it fixes it. But other than that I’m not too sure what the issue could be. I’ve taken the car on long drives and fans have never come on so it’s definitely not an issue of the coolant/engine not being hot enough.
 
LucasJ said:
Still using 4g15 radiator and fans. I haven’t had any issues with ac or heater. Engine bay is definitely hotter and retains that heat longer.

Until I figure out the problem, whether that’s putting in a 4g93 radiator and fan or whatever the fix is. I’ve just been turning the ac on when idling or in slow traffic, as that triggers both fans to come on. Whereas when driving above 30-40kph the air coming in is enough to keep the engine cool…ish

I’ve replaced thermostat, water temp gauge, coolant temp sensor, all ac/rad fan relays. The only thing not changed is the radiator and fans themselves. Could probably pick one up from a wreckers and swap them over and pray that it fixes it. But other than that I’m not too sure what the issue could be. I’ve taken the car on long drives and fans have never come on so it’s definitely not an issue of the coolant/engine not being hot enough.
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I’m also still using the 4g15 instrument cluster. Not sure whether the water temp reading on that would be different to a 93 cluster but it’s never gone above halfway.
 
LucasJ said:
Still using 4g15 radiator and fans. I haven’t had any issues with ac or heater. Engine bay is definitely hotter and retains that heat longer.

Until I figure out the problem, whether that’s putting in a 4g93 radiator and fan or whatever the fix is. I’ve just been turning the ac on when idling or in slow traffic, as that triggers both fans to come on. Whereas when driving above 30-40kph the air coming in is enough to keep the engine cool…ish

I’ve replaced thermostat, water temp gauge, coolant temp sensor, all ac/rad fan relays. The only thing not changed is the radiator and fans themselves. Could probably pick one up from a wreckers and swap them over and pray that it fixes it. But other than that I’m not too sure what the issue could be. I’ve taken the car on long drives and fans have never come on so it’s definitely not an issue of the coolant/engine not being hot enough.
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I did end up getting the thermo fan to come on. Your definitley not wrong regarding the engine bay retaining alot more heat. I had to let it idle for about 20 min without moving for it to kick on. I now have to investigate my aircon fan had that working everytime I turned the system on. when I was testing the thermo fan I couldn't get it on for whatever reason
 
LucasJ said:
I’m also still using the 4g15 instrument cluster. Not sure whether the water temp reading on that would be different to a 93 cluster but it’s never gone above halfway.
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Im also using a 4g15 cluster. My 4g93 Cluster fuel and temp wasn't reading. I saw some comments regarding the clusters either not being interchangeable or not being able to read fuel and temp. I stayed with my 4g15 cluster so I could have the readings, although I can't get my tacho to work on it. Had a bridging cable work on the 93 briefly but wouldn't turn off, not sure what that was about. I tried hooking up tacho signal and a ground and still no luck. I may be able to get my hands on a genuine evo 4 cluster. I saw mike lakes work and follow the wiring diagram from mirage fourums.net so I may go down that route.
 
Put an aftermarket thermo fan switch in, set it to 90 degrees. Done.
 
Phez2000 said:
Im also using a 4g15 cluster. My 4g93 Cluster fuel and temp wasn't reading. I saw some comments regarding the clusters either not being interchangeable or not being able to read fuel and temp. I stayed with my 4g15 cluster so I could have the readings, although I can't get my tacho to work on it. Had a bridging cable work on the 93 briefly but wouldn't turn off, not sure what that was about. I tried hooking up tacho signal and a ground and still no luck. I may be able to get my hands on a genuine evo 4 cluster. I saw mike lakes work and follow the wiring diagram from mirage fourums.net so I may go down that route.
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still no fix yet, but I decided to get a fiberglass vented bonnet to help with the heat....and it looks cooler aswell. Once i get around to it ill most likely swap out the fans and all the wiring for the ones from a 4g93, I'm like 15% sure that's the issue so not really too confident, otherwise it might just be a job of swapping out the instrument cluster, and pulling the dash loom (kill me) and putting in a 4g93 loom and cluster (Ill miss my white vrx cluster:( ) and once every single thing is from a 4g93 then the car should have no issues turning fans on.

It genuinely still baffles me that they aren't compatible between the 2 different engines. Everything else on the car works after all I did was swap the engine, loom and ecu but for some reason the fans just dont agree with being used on another engine.

I've also got plans to turbo the thing eventually so I wanna make sure everything works and is stock-ish before I do that.

But then again I haven't had any overheating issues at all and the car is an absolute blast with the 93 in it so I'm not in any rush to get it done.
Ill reply to this thread if any changes occur.
 
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LucasJ said:
still no fix yet, but I decided to get a fiberglass vented bonnet to help with the heat....and it looks cooler aswell. Once i get around to it ill most likely swap out the fans and all the wiring for the ones from a 4g93, I'm like 15% sure that's the issue so not really too confident, otherwise it might just be a job of swapping out the instrument cluster, and pulling the dash loom (kill me) and putting in a 4g93 loom and cluster (Ill miss my white vrx cluster:( ) and once every single thing is from a 4g93 then the car should have no issues turning fans on.

It genuinely still baffles me that they aren't compatible between the 2 different engines. Everything else on the car works after all I did was swap the engine, loom and ecu but for some reason the fans just dont agree with being used on another engine.

I've also got plans to turbo the thing eventually so I wanna make sure everything works and is stock-ish before I do that.

But then again I haven't had any overheating issues at all and the car is an absolute blast with the 93 in it so I'm not in any rush to get it done.
Ill reply to this thread if any changes occur.
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I ended up getting my thermofan to kick on. Now that I have been driving it around properly. But in saying that I think the ac fan doesn't work for whatever reason even tho I didn't touch it. idk maybe it needs gas for it to allow it to turn on. But thermo fan defenitley works. I noticed that the engine bay holds ALOT more heat the the 4g15 did. and regarding the cluster issue. I gave up on the 1.8 cluster and bought an evo 4 cluster still in shipping. I saw the main things work not sure about coolant and petrol guage, in the demo video looks like they both didn't move so we will see. when it arrives. fingers crossed
 
Phez2000 said:
I ended up getting my thermofan to kick on. Now that I have been driving it around properly. But in saying that I think the ac fan doesn't work for whatever reason even tho I didn't touch it. idk maybe it needs gas for it to allow it to turn on. But thermo fan defenitley works. I noticed that the engine bay holds ALOT more heat the the 4g15 did. and regarding the cluster issue. I gave up on the 1.8 cluster and bought an evo 4 cluster still in shipping. I saw the main things work not sure about coolant and petrol guage, in the demo video looks like they both didn't move so we will see. when it arrives. fingers crossed
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update. I got my evo 4 cluster everything works straight away no wiring..... apart from my temp guage :((((
 
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