loud roar when starting 4R

[TRD04RUNNER]

??? I notice that the 4R make a really loud roar when you start it. sound like a big ass fan then it is? but i only notice this with 4R? why does the fan kick in soo loud at start up??:zoom:

 

[mike_d]

do the new 4runners have the mechanical fan or is it electric? i know that my fan clutch is engaged during start up and makes the roaring sound. i never worried about it, every vehicle i've had with a mechanical fan has done that.

 

[TechWrench]

do the new 4runners have the mechanical fan or is it electric? i know that my fan clutch is engaged during start up and makes the roaring sound. i never worried about it, every vehicle i've had with a mechanical fan has done that.

It is a mechanical (silicone clutch) unit. And I don't have what I would consider any unusual fan noise on start-up. Do you have the gas pedal depressed on start up to make it rev when it starts?

 

[tkr128]

I've noticed this with the 3rd-gens, but my 4th-gen isn't as loud. I kinda like it, makes it a bit more masculine.

 

[iontrap]

I kinda like it, makes it a bit more masculine. [/B]

My wife made that comment when I got my Runner.

 

[Kanab]

Cold engine = no roar
Hot engine = roar

Has to do with the temp which engages the fan. If yours is doing it all of the time you have a problem with the fan clutch. Take it into the dealership. Warranty work time.

 

[TRD04RUNNER]

I think it sound loud to me it's because I started it everday in the garage and I guess the noise bounce off the wall and just make it sound loader then it it??

 

[mike_d]

Cold engine = no roar
Hot engine = roar

not quite true (at least in all the silicone fan clutches i've seen). everytime i start my engine the clutch is engaged, even if it's cold from sitting all night. the if it's cold the clutch will disengage real quick and you can hear the fan slow down, but every time the engine is started the clutch is engaged. my guess is that when the engine is off, the intermolecular forces in the silicone oil are strong enough to stick together and cause the fan to move, then as you start the engine, if it's cold then you start to break the bonds and the oil slips like it's supposed to, but it's not instant.

 

[EDGE]

It's normal, most all cars do it to some degree, usually cause on 1st start up the engine works harder to get to normal operating temp, thats also the reason for when it's colder out the tach will rise life your holding the gas pedal down:

I've always noticed it on cold start up or after it been sitting for awhile, if it is hot and I start it up it's good to go:

 

[CMiYC]

I kinda like the roar.

When I'm in the garage it sounds like the 4r is pissed. Makes me smile. :-D

I've noticed other small V8's (Tahoe and F-150) do similar. Its most likely just the fan kicking on and the engine reving kinda fast during warm up.