Overheating: Radiator Fan Issue?

[HeX]

After a leisure 50-60 mile drive the other day, my temperature gauge began to climb up to 3/4 of the way. It normally operates at about 2/5 of the way. I turned on the heater and I was able to drive home with the temp. needle at half. I verified there are no leaks anywhere and there is no foaming in the oil to indicate a potential head gasket issue. Once the engined cooled down, I checked the fluid to find it was a bit low so I filled it up. Since then Ive driven it & it seems to warm up quicker than normal. After about 15 minutes it starts to climb again. I just removed the radiator cap and ran it for 30 minutes with the heater on full blast and it stayed on the low bar of the gauge. I then turned off the heater for another 20 minutes and the gauge leveled off at about normal. The fluid did not fluctuate either. It seems the radiator fan never kicked on in the many times in inspected the process.

Thus, I'm leaning toward the issue being either the fan motor or fan relay. If it is the fan motor, is it worth replacing or should I consider upgrading the fan altogether? Please let me know if there's a way to verify one or the other being the issue. Your expertise & suggestions will be appreciated.

 

[2slo4u]

I would change the thermostat.

 

[ReedMann]

Yeah it sounds like the thermostat. I'm pretty sure you can just run a 12V wire and a ground to the fan connector to test if it is working on not. If the fan works then your thermostat is not opening.

 

[HeX]

UPDATE: It was the thermostat! As you can see below, it was shot! There were even wax bits in the coolant from the internals leaking (I looked up a video on how thermostats work to know that they have wax inside). It definitely isnt a Honda part and it looks like it hadnt been changed in a long time. I drove about 30-40 miles with the new Honda (Denso) thermostat and the temperature is stable. I must add it was remarkably easy to swap it out,even with the seal being quite baked onto the housing.

 

[lethal6]

Thermostat failure is a very common cooling system problem. Next time start there.

 

[mymmeryloss]

Good stuff!

 

[2slo4u]

Glad it was an easy fix.

 

[HeX]

I'm resuscitating this thread due to a fan issue yet again. It actually still may be the same reason why the fan didn't turn on back then but I hadn't noticed because the car doesn't overheat anymore.

Anyways, the fan is not turning on. I confirmed that it works with direct power. I also swapped in another fan relay but nothing changed (I went off the diagram below). I confirmed it is the Coolant Temperature Sensor by using a wire to jump the harness pins and the fan turned on. I've seen that another test is to submerge the sensor in boiling water then test it with an ohm meter. It seems to me that the jump-pin test makes the most sense.

My question now is if its safe to leave a jump-pin in the sensor harness until I buy a new sensor, for longer drives that is?

This is the sensor...

 

[Anthony_76]

So I had this exact issue as you did.
And the fan relay was good as was the fan motor. I jumped it and grounded it to the body and the fan came on.
I even bypassed the thermostat switch and it never would come on.
That left me only one option.
To run a switch to turn the fan on and off manually.
So that's what I did.


By the time I was done, you could hardly tell it was there.
The switch has two tabs on it, one you will ground to the steering wheel column the other is the main power from the battery.
Flip the switch the fan comes off and on.
You just have to remember to turn it off though. (You can hear it though)

 

[HeX]

I already ordered the sensor. I also read elsewhere of the idea to add a switch to it but I rather not rig it. You should add a picture of the switch too.

 

[TS2008]

Did you sand the contacts ? Sometime this could caused by the oxide on the contact surface. But since you already ordered the switch, it's better to put a new one instead to find out what's the problem with the switch.

 

[HeX]

The new coolant temperature sensor came in today and I installed it using a 15/16" long socket with an extension and it was pretty easy. I preferred changing the sensor because the old one looks to be original. I figure I'll know for sure that it works after a long drive tomorrow.

 

[HeX]

After about two weeks and a roughly 500-600 mile road trip last weekend, the fan is functioning just fine now.