2018 M3 CS Carbon Fiber Roof

[rsbillings]

My M3 CS has just 15,000 miles on it and is garage kept. Several botches - kind of white in color or much lighter than normal color of the carbon fiber roof. I need help to figure out why this is happening and how I correct the problem. The car otherwise is in mint condition inside and out.

[omega2733]

I'm actually really close by you in the area. If you haven't PPF'd the roof, you're probably going to see the issue.

The epoxy/clear usually fails, especially in florida in strong UV and will need to be recleared. Pictures would help, I can also look at it since I'm local to you.

[rsbillings]

First - thank you for responding. I'll take some pictures and upload later today after work. The car has always been garage kept - very little exposure to UV rays. 2018 with only 15k miles - I averaged about 2,300 miles per year (mostly track time). Also - when I took it to the track - it was covered until race time. Let me post some pictures of the affected areas - which display really crazy patterns.

I'm in Deland - where are you located?

[omega2733]

I'm also in DeLand

[M3SQRD]

Does it look like your roof got hit by rocks/debris? Local damage can cause local delamination and change in color, usually a whitish-yellowing color. Unfortunately, this can happen at any mileage so your low mile garage keep car isn’t immune to this type of damage.

[tempted]

It's the clear coat failing on the CF roof. I also have a 2018 that has the same issue. Multiple small blotches that can be seen with the correct lighting.

Note that I consider myself well versed with automotive detailing so my car like yours has been taken care of.

Be prepared for getting it recleared.

[M3SQRD]

Originally Posted by tempted

It's the clear coat failing on the CF roof. I also have a 2018 that has the same issue. Multiple small blotches that can be seen with the correct lighting.

Note that I consider myself well versed with automotive detailing so my car like yours has been taken care of.

Be prepared for getting it recleared.

It’s a gel coat, not a clear coat, on the CF roof. All of the old coating has to be removed (peeled off), the CF prep’ed for the new gel coat, and gel coat installed. However, if the CF has delaminated, it’s a much more challenging process, if it can even be done.

[tempted]

Originally Posted by M3SQRD

It’s a gel coat, not a clear coat, on the CF roof. All of the old coating has to be removed (peeled off), the CF prep’ed for the new gel coat, and gel coat installed. However, if the CF has delaminated, it’s a much more challenging process, if it can even be done.

So you're saying that the roof has no clear coat on it?

I think you're sorely mistaken. If that was the case, the gel coat would yellow like the CF hoods you purchase from VIS or Seibon.

Pulled one example from a reputable shop

https://2mautowerks.com/service-pack...r-coat-repair/


In this case, I do agree that it could be the gel coat delaminating from the top cf layer.

Suggestion, take it to a bodyshop and they will set you on the right path.

[SYT_Shadow]

You can get it fixed in a paint/body shop.

Gts2 had some weird color changes in the roof and a shop was able to fix it perfectly.

[M3SQRD]

Originally Posted by tempted

So you're saying that the roof has no clear coat on it?

I think you're sorely mistaken. If that was the case, the gel coat would yellow like the CF hoods you purchase from VIS or Seibon.

Pulled one example from a reputable shop

https://2mautowerks.com/service-pack...r-coat-repair/


In this case, I do agree that it could be the gel coat delaminating from the top cf layer.

Suggestion, take it to a bodyshop and they will set you on the right path.

It uses a gel coat instead of a conventional sprayed clear coat. There are multiple diy threads in this and the m3post forums showing the repair process and none of them use a conventional clear coat.

Here’s a video showing the application of the gel coat:

[tempted]

Originally Posted by M3SQRD

It uses a gel coat instead of a conventional sprayed clear coat. There are multiple diy threads in this and the m3post forums showing the repair process and none of them use a conventional clear coat.

Here’s a video showing the application of the gel coat:

Not sure why your so adamant that clear coat is not used in the process. What do you think they put on top of the gel coat?

Like I said in my post above. Gel coat yellows due to poor UV protection. Clear coat goes over the gel coat.

Feel free to google it.

[M3SQRD]

Originally Posted by tempted

Not sure why your so adamant that clear coat is not used in the process. What do you think they put on top of the gel coat?

Like I said in my post above. Gel coat yellows due to poor UV protection. Clear coat goes over the gel coat.

Feel free to google it.

Regardless of what is applied, it still turns yellow with age if not properly cared for.

[rsbillings]

I did not get a chance to take pictures because of the intense rain on the day I had time to take pictures. Yesteday I took some pictures - but the clare and reflection are a problem. I am going to try again today with my 35mm camera instead of my phone.

[rsbillings]

Originally Posted by M3SQRD

Does it look like your roof got hit by rocks/debris? Local damage can cause local delamination and change in color, usually a whitish-yellowing color. Unfortunately, this can happen at any mileage so your low mile garage keep car isn’t immune to this type of damage.

No - there is no damage at all; later I will take pictures and post

[rsbillings]

Originally Posted by omega2733

I'm actually really close by you in the area. If you haven't PPF'd the roof, you're probably going to see the issue.

The epoxy/clear usually fails, especially in florida in strong UV and will need to be recleared. Pictures would help, I can also look at it since I'm local to you.

Finally - got some pictures to show the spots. These spots are not the result of rock chips, lack of care, peeling , or yellowing. These spots are odd shapes and patterns, seem to be underneath the coating and just not normal. I believe they are the result of faulty materials and/or workmanship.

[bvrider1]

Wow, not really sure what to make of those defects. Are you the original owner? It's almost like it's coming from the underside, like inside the car. Weird!!!

[tempted]

It's body shop time. No matter what caused it, it's going to require some work.

[hC1001]

Looks like delamination... I believe it will get more brittle and chip away with time...

To fix, you'll need to get the old coating completely off and find a place that is experienced with CF roof repair...

[SYT_Shadow]

Originally Posted by rsbillings

Finally - got some pictures to show the spots. These spots are not the result of rock chips, lack of care, peeling , or yellowing. These spots are odd shapes and patterns, seem to be underneath the coating and just not normal. I believe they are the result of faulty materials and/or workmanship.

I'm not posting the photos here, but I had a gts that looked very similar. It was 100% repaired by a local shop. They sanded it down and applied a new coat.