Can anyone throw any light on this....since the snow/cold weather has started, on start up when the front/rear heated screens come on there is what can only be described as a rattle type noise. If the heated screens are switched off the noise stops and after a minute or two when the screens are switched back on the noise does not return. Could this be related to the alternator? All belts have been replaced when the timing belt was done (many thanks to @Stef123) and other than this the car drives as normal, no noises if I switch the heated screens off and just drive off.

Car is a 1.6 petrol (non vct) focus mk2 facelift with 62000 on it.

It could just be the additional load pulling the idle down to the point where the engine shakes a bit. What happens if you just increase the revs slightly to, say, 1000rpm?

13 minutes ago, mjt said:

It could just be the additional load pulling the idle down to the point where the engine shakes a bit. What happens if you just increase the revs slightly to, say, 1000rpm?

As it’s already cold the idle is above 1000 anyway, if I rev the car it gets louder! Not wanting to ‘chance’ anything as soon as I start the car, the windows get switched off then after say 20/30 seconds I switch them back on with no noise. As I said once I drive off there is no noise from the car so I don’t think it’s a heat shield/mechanical type of rattle.

Could it be pinking/pre-ignition from the cold start advance and extra load or not that sort of rattle?  

On 03/03/2018 at 12:06 PM, TomsFocus said:

Could it be pinking/pre-ignition from the cold start advance and extra load or not that sort of rattle?  

I had a listen with the bonnet up this morning and it wasn’t as bad but sounds like coming from the bottom pulleys area. I’ve had the manifold cat replaced a few months ago so it could also be something associated with that so I’ll keep my eyes and ears open.

** edit: I think I’ve found the culprit.....there’s a bit of shielding against the bulkhead that has been distorted when they’ve done the ‘manifold cat’ and it’s ‘awfy’ close to the heatshield where the O2 sensor is, I think when the load pulls the revs down slightly causing the engine to shudder slightly the 2 heatshields are making contact so once the rain/snow stops I’ll get out and manoeuvre the bulkhead heatshield back into place. 👍🏼

Edited March 6, 20188 yr by Russ