Radiator fan stuck on


jesse888

Ek9+Turbo+Nurburgring= Heaven
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So, was going to save this for the build thread but I started the engine today! Silky smooth and you can't even tell it's not a complete stock b16b! Chuffed with it so far.
Was warming it up, then it got to 60c(ish) and the rad fan comes on and stays on.
I had to pull the plug on it to get the engine up to temp.
What could cause the fan to stay on? I'm thinking I've got a plug or pipe mixed up somewhere but obviously don't know what I've got wrong.
I have a spare plug that's sitting under the inlet manifold(identical to iacv plug) could this be anything to do with it?
 
Is it all the wire harness original ?
Could it be something to do with temperature sensor switch ?
at least is working not the other way around.. lol
 
Probably the fan switch on the back of the thermostat, try running it and in plugging that plug.

I'd bet the spare plug down the back is the old power steering sensor(assuming you did remove the power steering)? as that's the same as the iacv plug
 
Will try that tomorrow.
Had the coolant hoses for the head alittle wrong compared to my mates dc2.
So changed them over and refilled the coolant. Still came on early but I'll keep trying.
The temp switch in the thermostat literally just unplug it and run the engine?
 
You don't have a low temp fan switch in? :lol:.

But on a more serious note, sounds like a fan switch issue.
 
Excellent, will mess about with the fan switch tomorrow and see what's what.
 
Disconnected the fan switch, fan still came on early?
I've got a spare oem fan switch I'm going to try along with 2 new coolant temp sensors(gauge sensor never worked anyway) hoping this fixes the issue!
 
Temp sensor maybe buggered? Mates accord throws fan on all the time sitting still and it's his sensor that's buggered
 
New temp sensor on the way
 
Right.
Two new temp sensors(interior gauge didn't work either)
Swapped thermostat for known working one and fan switch for known working one.
Fan is coming on at 75c but switches off again at around 70c so better than before but still not right.
I'm thinking my aftermarket gauge sensor is dodgy but open to suggestions?
 
I've no idea, I'll ask romain but I'm not sure he would have adjusted that tbh.
Clearly something was wrong before that isn't now as the fan goes back off again instead of being constantly on.
Checked the old thermostat and it works fine.
 
Could bad earths cause this? I'll take any suggestions.
 
So it continues, driving to work this morning (2.30am) and I couldn't get the temps above 50c. That's a half hour drive too so should have been hotter than that!
Think I'm going to stick an oem thermostat in, the two I've got say 78c on them, assuming this is opening temp.
 
Think 78 is the oem opening temp,

Fan still getting stuck on below 50c?
 
Think 78 is the oem opening temp,

Fan still getting stuck on below 50c?

Really? That not abit low?
No the fan now comes on at 75c after changing coolant temp sensor. I've found a tiny coolant leak from one of the iacv pipes. Will sort that tomorrow.

The sensor I bought says made in China on the Honda sticker, I got it from a vendor on here and asked for an oem sensor so I'm hoping that's correct and it's not a copy or something
 
Pretty sure Japanese thermostats are lower opening temp. 78 to our normal 82.
I remember ordering a thermostat from Autodynamics Honda in Singapore and it was 78 degrees
 
Would make sense that both of mine are 78c, one in my b16b had never been changed(in England atleast)
So that's that then, next problem is this fan and why can't it make temp? You'd point to thermostat stuck open but I know it isn't!
 
When I pulled up from work I squeezed the rad pipes and they had pressure in.
Got it up to temp without the fan and then I plugged it in the pipes went a fair bit softer.
This mean anything?
I mean most issues with coolant system end up with over heating, not under heating lol
 
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