Fan clutch question

[Cloud Strife]

I changed my oil out yesterday and my engine temp was cold. It was a 40 degree day. But as soon as I started up my engine, the fan was running at a pretty good speed.

I thought that the fan wasn't supposed to become active until a certain temperature was reached.

This is on a 99 blazer 4x4 4.3 vortec.

[scholzee]

You can search on the topic and there are many descriptoions from people more knowledgeable than me. On my 1996 at startup and for a few minutes ( less than 5 ) the fan will roar, some say it is because the fluid settles when sitting and it slightly engages at start up. I would not worry about it as long as mechanically things look ok, such as ENGINE OFF if you grab the fan and try to wiggle it to make sure a bearing is not bad or something loose. Usually whne the cltuch fan goes bad it shows up as not engaging when in stop and go traffic or at idle the engine temp will tend to overheat. On the highway there is enough air flow through the grill to the radiator to keep things cool.

[Cloud Strife]

That is why I am asking as there is very little consensous on this. Some are trying the theory of spin the fan while cool and spin it after the engine is warm.

[MT-2500]

Hand spin does not tell you much.
When they are cold they will turn quit a bit.
They are controlled by a thermostat in the fan clutch.
They should idle warm untill around 200-210 degrees rad tempt and the kick in full force.
You can feel the air blowing by holding your hand a few feet behind them or hear it when they do.
If they do this it is good.
MT

[Cloud Strife]

Well mine turns no matter what temperature.

[MT-2500]

Just turns or blows full force all the time?
If blowing full force all of the time it is time to replace it.
MT

[BlazerLT]

Yea, it will turn a bit all the time, if it doesn't, you have problems, if it full roar, you also have problems.