Radiator Fans wont turn on help Diagnose!

[BostonGST]

Was driving about 5 miles, when I stopped I heard a noise from under the hood and my overflow tank was bubbling out coolant. I let it cool for an hour, refilled overflow and turned the car on to see if the fans would kick in. Nothing, turned on the heat and AC full blast, nothing. Tried a new fuse. Then hotwired it directly to the battery and it turned on. I taped it up and drove it home like that so it wouldn't overheat.

On the way home I made sure to look at the temp guage and it was at half way the whole time. Could it be the coolant temp sensor? But if that was the issue wouldnt the fans turn on when I blasted the heat/AC?

Also, if I got some real equipment and had the fans run through the battery and 30A fuse to always be on would that be bad in any way? Hurt performance ect.

 

[spyderdrifter]

It could be your ect, the t-stat, bad radiator cap, or even something else. Test each one. The cap should hold 13 psi, the t-stat should open between 180°-200°. There should be a post on here about testing the ect sensor. Make sure to properly burp your coolant system if you remove any of those parts. You can remove the cap without needing to burp it if the engine is cold.

 

[bo0st]

If you have ECMLink you can turn them on manually under the Misc menu.

In Misc you'll see it under "Devices & Diagnostics"

Just hit the check box where it says Activate fans full on and if they don't turn on you know you got a problem for sure.

 

[BostonGST]

pulled the thermostat and through it in boiling water and it didn't open. I was thrown off, thought the temp gauge would still be reading hot/max if thermostat was bad, mine was sitting in the middle the whole time

 

[Mauispyder]

I recently changed my thermostat. I threw the 16 year old one into boiling water. No change. I threw the new Stant thermostat into boiling water. Also no change. I ordered a new Mitsubishi thermostat and installed it (didn't throw it in boiling water). All good so far.

 

[Mauispyder]

For what it's worth, I've had overheating on my 2g twice. Both were related to loss of cooling system pressure. First time the housing the thermostat cap sat on had a tiny corrosion defect. Kept changing caps without fixing the boil over. Finally found the defect and filled it. The second time a 16 year old clamp on one of the small front coolant hoses gave up losing pressure and coolant in the process. Silver lining was it inspired me to do my water pump and timing. Sorry I don't know much (yet) about fan troubleshooting.

 

[dsmrafa]

hi, i would double check the relays of the fans.... sometimes they are not all into the socket and they don`t let the fans fuction well, also check if they turn on in the moment you unplug your temperature sender, if both fans turn on then all the wiring is ok... plug the conector back in... and just if it is necesary change the fan relays....


have a nice day

 

[BostonGST]

Awesome tip, didn't know unplugging temp sender would do that!! Will try tomorrow, thanks! Also at first when I put the thermostat in the water it didn't open, decided why not and tried again and it did open.. going to replace anyway and hopefully that's it

 

[dsmrafa]

thats good, hope the problem gets solved!

 

[luv2rallye]

thought the temp gauge would still be reading hot/max if thermostat was bad, mine was sitting in the middle the whole time

Temp sensor needs to be in water for accurate measurement. Usually upon overheating the water is half gone. Check the things spyderdrifter says in post 2. ECT test: http://www.dsmtuners.com/threads/bucking-for-a-couple-of-minutes-after-start.385461/#post-152374418

 

[BostonGST]

Tried the thermostat this morning and it opened fine, put everything back together.. Unplugged the temp sender and fans kicked on! And plugged in and everything works. So not sure what initial problem is, thermostat was stuck and now opens or my temp sender was messed up, i'm going to replace both with OEM to be safe, thanks for all the help!!