radiator cooling fan

[bosco]

In the 2005 C6 there is one big cooling fan. My questions are does it have 2 speeds? I noticed mine running but wisper quiet when first started and after driving and heated up it was running faster and louder indicating there are 2 speeds. my fan was on when first started running in low I presume because it was quiet and just wondering how often that fan runs. I did have a tune and believe some minor adjustments as to when the fan comes on so maybe that has something to do with it. Just thought it odd to be on at all when first started but really never payed attention to it before.

thanx for replying
bye

[zidane]

The speed of the fan is variable all the way and the computer (ECM) controls it.
thnx for asking

[worldguru]

The speeds are variable by %. The speed of the fan is determined by the programming related to engine coolant temperatures and air conditioning line pressure. I have my fans set at 90% across the provided temp range, and it keeps my coolant around 185F at all times.

hope i may be of some help