I just noticed that my readiator fan starts when I start the motor .Is this normal on a 2.7L ?I thought the fan only kicked in when the coolant temperature reached a certain point .Could this be why it takes so long for my motor to heat up?

 

Yes, it is normal for the fan to spin when the motor is running, it is an belt powered fan. You are probably thinking of an electric fan. How long does it take to warm up, under average conditions my 2.7's always got up to temp within a few miles. When it was single digits or lower they took a bit longer. Some may say I'm crazy but try not to use your heat until the truck is up to temp, and I mean not at all, turn the dial all the way to cold and put it on recirculate until its warm, then turn on the heat. The heater core is like a small radiator and will increase warm up time, it is very minimal but you may be noticing that.

 

It takes about 7 to 8km on the highway .

 

Is it an electric fan or clutch fan? A clutch fan will spin when the motor is on, but not be engaged. It will only engage when the temp gets warm enough for it to. Can you spin it when the rig is off and cold (not been run in a while) ?

 

The fan on a V6 will do exactly what you described so I imagine it is normal on the 4cyl as well. I think it comes on automatically to put more load on the engine to get it to warm up faster actually. Since the thermostat doesn't open until the motor warms up, there is no coolant flowing through the radiator on startup and any air flowing over it won't do much to cool the engine anyway.

 

Bingo! That is unless the t-stat is stuck open.

 

from what Ive read/learned about viscous fan clutches is that when the fan is not spinning for an extended time (overnight) the oil inside will settle to the bottom of the clutch and will provide drag when you first start it, once its spinning centrifugal force distributes the oil evenly around the clutch and the fan disengages

 

You make a good point too mt_goat. If the OP's t-stat is stuck open, it is going to take longer to warm up.

 

I have the 2.7 in my truck. Yes the fan is always on, it's belt driven. As mentioned some vehicles use an electric fan or clutch which only run when the engine temp gets to a certain point.

7-8km sounds about right for warming up in the morning. about 3-5 minutes.

And yeah if your thermostat is stuck open your engine will take a looooong time to warm up. One way to check that is:
1. start your engine (when it's cold)
2. feel the return line to your radiator. when you squeeze it, can you feel fluid moving through? It shouldn't be moving when you first start since the thermostat would be closed. once your engine warms up, you'll be able to tell the fluid is moving through.

 

This is correct.

All 4Runners and pickup trucks, 4 or 6 cy, use a viscous fan clutch. It has fluid in it that engages the fan at certain temperatures. Yes, your fan is spinning all the time, but its not "engaged" fully, meaning its not under a load.


These fan clutches do fail, and they can stick on, so the fan would be going all the time. Or, they could fail where they don't come on at all and cause an overheat.