Overheating with fans on

[blueshark123]

So I have s13 sr with a aluminum koyo altima fans 50/50 coolant with watter wetter new nismo thermostat and new waterpump. No clutch fan.I also jacked the car to bleed till no bubbles were present. I also have no heater hoses connected. So when i am drivng my car and when i turn on the altima fans the car starts to overheat but when i turn it off it runs at normal running temps till i stop at traffic lights then i will need to turn the fans on it initally warms up and then cools down after sitting for 2mins. During Summer the car ran fine with no thermostat. What the hell could be the problem im stuck.

[Ninjabread]

Short in your wiring?
Don't see how turning on the fans would make it hotter.

[blueshark123]

yea its not a short because i wired them to a switch and that wouldnt make sense if there even was a short how would that cause it to overheat

[blueshark123]

I also have a arc 1.5 radiator cap i know when i turn on the fans it reliefs some of the pressure from the hoses but thats all i can tell that happens

[Ninjabread]

How does turning on the fan relieve pressure from the hoses?

Maybe your water temp gauge is playing tricks on you.

[alexrad]

your fans may be blowing air the wrong direction?
is it pulling air in, or blowing air through the front of the car?

i did that once.

depending on the motor on the fan, you can just swith the positive and negative wires, and it ill make the fan go the opposite direction.

or

you could try to mount the fan in the front of the rad. haha.

[blueshark123]

the fans are mounted inside the engine bay pulling air in towards the engine bay

[fliprayzin240sx]

How do you know its overheating? After market gauge or staring at the stockies?

[axiomatik]

and did you check that they spun the right direction? as alexrad said, on most fans, if you filp the 2 wires the fans will spin in the opposite direction.

[blueshark123]

How do you know its overheating? After market gauge or staring at the stockies?

Staring at the stockies but i do have a new temp sensor installed

[blueshark123]

and did you check that they spun the right direction? as alexrad said, on most fans, if you filp the 2 wires the fans will spin in the opposite direction.


Im pretty sure there wired in correct cause they flow the same way as my maxima stock one does so thats what im basing it off.

[98s14inaz]

and did you check that they spun the right direction? as alexrad said, on most fans, if you filp the 2 wires the fans will spin in the opposite direction.

I'm with you on that one. Just because they are on the inside doesn't mean they are pulling air. Check your wiring again and make sure the fans are pulling air in and not pushing.

[blueshark123]

they pullin air in felt it pulling air i put my hand on the radiator and felt the air being sucked in towards the engine bay.

[sillydrift]

i know you said you put in a new thermostat, did you make sure the little jiggly thing was on the top?

[blueshark123]

i know you said you put in a new thermostat, did you make sure the little jiggly thing was on the top?

yes for sure it was at top I also did test out the thermostat in a hot water pot and it opened up fine

[g6civcx]

When cruising on the freeway, you will overheat if you turn on the fans.

When you are stopped or driving at low speeds (below highway speed) with no fan on, air pressure in front of radiator = air pressure behind radiator = no air goes through radiator = overheat.

When you are stopped or driving slowly with the fan on, air pressure in front of radiator > air pressure behind radiator due to vacuum effect of fan = air goes through radiator = no overheating.

When you are cruising at freeway speed with the fan on, air pressure in front of the radiator is actually < than the air pressure behind the rad. because the spinning fans create resistance = no air through radiator = overheat

When highway cruising, turn off the fans. Air pressure in front of the radiator > air pressure behind the radiators with the fans freewheeling = air through rad = no overheating.


Electric fans are supposed to be turned off on the freeway. You don't need it.

Also, both clutch fans and e-fans are supposed to freewheel if the air is pushing the fans faster than the fan motor/pulley. This allows the fans to freewheel and create low pressure behind the radiator. If the fans hold a steady speed and you're going fast, the spinning fans create a lot of resistance and air doesn't want to fight the fans. Air will go around the radiator = overheat.

Provided you installed the thermostat correctly with the jiggle valve facing up, all your hoses are tight, no air in the system, then I would check the fan motor and pulley themselves to see if the fans can freewheel like described above.