headlights dimming and engine whirring on warm up

[mason001]

hey guys,

over the last few months i've had this problem where when the car is warming up for the first two minutes or so, the headlights will dim intermittently for a few seconds a time and when it does there's a strange whining/whirring noise from the engine. to try and rectify this i've got a new battery, new alternator and had all the earths checked and cleaned.

whilst i've had this problem i've not had a stereo installed as it seemed to drain the battery. after having the earths done the car seemed to be working 100% fine, so i thought i'd put back in my head unit, but as soon as i did the problem occurred again! so i took the unit back out, but the car is once again whirring and dimming.

any ideas as i'm coming to my wits end with it now!

cheers.

[javalin]

Radiator fan kicking in randomly?  Alternator belt slipping?

Anything else on whilst it does it?  Try with everything switched off and see if you can isolate something.

[MoshiMoshi]

This is surely normal? It will be the radiator fan kicking in and out as determined by the thermostat. Perfectly normal if you are idling/not moving. If it does it while you are driving along, then there may be cause for some concern.

[danny_p]

headlamps dimming combined with whiring is a sing of heavy electrical load.  a lot of power is been pulled so voltage drops alternator starts working hard the belt will make a whirring noise as its transmiting a lot more power.

my skoda diesel dose this when it's cold for a bout the first five minutes of driveing you can hear a relay click and the lights dim for a few seconds then t clicks and returns to normal.    i just ignore it as its allways done it and dosent seem to be developing