alirzn

Hi Guys,
There are some cracks on the paint of my 2004 530I hood. The color is dark blue and I am not sure why it happened? I think it is because of the sun. Here I have attached the picture. Does anyone know how I can fix that? It is on the hood and it does not look nice. thanks
Attached Thumbnails

545iMike

Its called checking. Deterioration of the finish from uv rays. Only way to repair is to re-paint the hood.

alirzn

why it happens?
I prefer to not re-paint it. Do think that polish or wax like turtle wax black box can help to make it looks better?

545iMike

Its from the sun breaking down the paint. Polishing is going to thin the clear coat out more probably making it worse. Waxing will fill the cracks just highlighting them more. Try anything you want but your going to have to repaint the hood to make it completely disappear.

west

Thanks for the post. Interesting.

alirzn

Do you think that insurance cover that?

545iMike

No. Its wear and tear.

tonyb635

I know this is an older post. If you have this condition it will require repainting. However, before it can be painted there are a few things that will have to be done first. Just a simple sanding, priming and painting will not be enough. If this occurs you will have to ensure the structure under the paint is cared for. More than likely it will need to be taken all the way down to the metal. So make sure you tell your body shop to do this. Sometimes short cuts will be taken and only sand away or fill the paint which could leave the same condition in the primer and it might not be visible. If you re prime and paint over this condition it will look nice for a short time then the cracks will return with vengeance! Looking at the hood in the pic. I wonder if there had been a previous repair ? If you are tye original owner then you would know for sure if there was a previius repair there. Otherwise buying ysed you would probably not know this. If so this condition could have been created due to someone waxing the paint before it was fully cured. Also this condition can be caused by a bad repair in general by the shop. In a situation like this, it's not common to be caused by sun since this appears to be somewhat isolated. Normally sun won't focus on one specific area. But sun can cause similar type of these issues.

545iMike

I agree with you that initially it was a bad repair/ material/ finish application that has been applied to the hood, but it is the environment that broke it down and caused the reaction. Drastic temperature change/ uv-rays etc. If it happened right after coming out of the body shop then it would have been a similar root problem, ie the finish, but the cause would be from solvent escaping the finish too quickly. But going from the info given buy the original post, nothing saying "I just got my car back from the shop and...," I'm forced to believe that its an aged finish and the environment is to blame. And your correct in removing the finish of the hood to completely repair the problem. Any layer could have caused the reaction. Filler/ primer/ sealer/ base/ clear.

tonyb635

Yeah but it also doesn't even have to be a bad repair. Could have been finished out correctly and then a sealer/wax applied well before the materials had time to properly cure and breathe out. Most people that have their car painted or repair receive the information from the shop to not apply wax for a certain time frame. I've been painting for over 30 years and I never seen sun damage just one spot in the center of a hood or panel, sure the entire panel, top surface of the car just not such an isolated spot like in then case, unless like I said there was a repair made, then obviously the new paint is not the same as the original paint and if the OP is not the original owner then they may have never known a repair was made to the hood and then apply wax etc too early. I know on my spare truck that I painted 5 years ago, the paint has really held up well. I noticed that the cowling look to be very dry and the clear was flaking. No other place is like this. I am pretty sure this panel is galvanized or at least aluminum and think this might be the reason behind it's behavior.