Hi gotta problem my 3door has a real NASTY habbit of blowiing out sunroofs at HIGH speeds ive lost 2 complete roofs & only just managed to keep my 3rd one ive now put gaffa tape round the front edge of the roof & DONT hit any big speeds (annoying). any ideas pls

 

Hi . it sounds like there just not fitted correctly . Make sure that it a good tight fit and that the rubbers on the front of the roof is sitting down good and flat as at speed wind could be getting under the rubber lifting it like a kite. I take it this happens when you have it completly closed.

Regards

Dave

 

how do you manage to blow sunroofs out they are bolted to the car

 

3 doors did have a habit of this, set the front edge -2mm and the rear edge +3mm, that's how mine is set on me sapph, speed is not an issue even in heavy wind.
tabetha

 

It could be a pressure build up inside the car contibuting to this; - you haven't done anything to block the ventilation holes from the cabin to the outside have you?

Seems unlikely that you would fit three very badly adjusted roofs. Hence they might be blown out by increased air pressure inside the car at speed.

 

Its not an aircraft mate and nothing to do with pressure in side the car . as i said id reckon its to high on the front or wind getting under the front rubber . No offence mate.

Regards

Dave.

 

Lol, - whatever you're obviously an expert.

How much would that sunroof have to be out of alignment for the air to get underneath and pull it off? And three times? I really doubt this bloke has fitted three roofs and not checked the front alignment.

At high speed the ventilation system scoops up exponentially more air as the car accelerates; - this is transferred to the cabin. The vents in the door bottoms and rear quarters are designed to let this air out and equalise the pressure so you don't get a differential between the inside and outside of the car with the windows shut. The sunroof is quite vulnerable to this pressure because the glass isn't physically held in a track like the windows are. Plus when you're going at speed the roof of the car acts like a wing and the air pressure above the roof is lower. This is a fact. The combination of low pressure on the outside of the sunroof and high pressure on the inside can lift the roof out of the car, then the wind gets underneath it and pulls it right off. This would be compounded if the roof is not fitted correctly.

This is quite a common occurance on some cars; - check Google and see for yourself.

 

omg i dread the thought ive never heard of sunroofs flying off cars!

 

Holes in doors are for WATER to drain away, that is rainwater that hits the glass and falls down past the rubber seal, the door should be pretty sealed to the inside cabin, that is why there should be a plastic sheet over the hole door.
It's a fitment or mechanism problem that's causing it.
It is not such a problem on sierras with ventilation, but certainly is on newer cars as makers try to get them ever more silent, adequate through flow of air decreases as it promotes noise.
You could always fit the sunroof deflector, this also allows the roof to be wound back and cuts down on noise massively..
tabetha