Alpine white paint yellowing

[Ben Ingraham]

Has anyone experienced paint yellowing on the rear bumper? It's close to the exhaust and I'm wondering if a catless set up is changing my paint color.

[Beemdog]

I've had this on no-cat muscle cars, but found if you go after it regularly with a good liquid cleaner wax, it came off pretty easily. While it is possible to discolor the paint all the way through, most of the time on newer cars the discoloration is just on the clear coat and will rub out.

[rjd598]

this issue has come up before on alpine white cars. try polishing to see if it will get better

[///M Power-Belgium]

Originally Posted by rjd598

this issue has come up before on alpine white cars. try polishing to see if it will get better

Indeed .
Step 1 => Hand wash
Step 2 => Clay bar
Step 3 => Polisch
Step 4 => Sonax Polymer Netshield to prevent further contaminations

[whats77inaname]

Bump.

I'm having the same issue w/my HFC cat setup. I picked up a random orbital and a Nanoskin pad along w/some Glide to clay it, and some Sonax Net Polymer to seal it. After the Nanoskin, there is still some discoloration. I'm thinking I'll have to compound/polish to get the discoloration out. Given that, I've been looking @ this thread ft. the Sonax Paint Cleaner, as well as reading the reviews on the Merzerna FG400.

Any input would be appreciated.

[rjd598]

Originally Posted by whats77inaname

Bump.

I'm having the same issue w/my HFC cat setup. I picked up a random orbital and a Nanoskin pad along w/some Glide to clay it, and some Sonax Net Polymer to seal it. After the Nanoskin, there is still some discoloration. I'm thinking I'll have to compound/polish to get the discoloration out. Given that, I've been looking @ this thread ft. the Sonax Paint Cleaner, as well as reading the reviews on the Merzerna FG400.

Any input would be appreciated.

i briefly looked into the subject a few years back when it happened on my dad's e90. it seems to be a common issue on alpine white paint from bmw. not sure if detailing will 100% correct the problem

[whats77inaname]

Originally Posted by rjd598

i briefly looked into the subject a few years back when it happened on my dad's e90. it seems to be a common issue on alpine white paint from bmw. not sure if detailing will 100% correct the problem

For me, the paint isn't really yellowing. It's more that it looks dirty.

[rjd598]

Originally Posted by whats77inaname

For me, the paint isn't really yellowing. It's more that it looks dirty.

then your plan of action is a good one as mentioned above

[r1762]

Originally Posted by ///M Power-Belgium

Indeed .
Step 1 => Hand wash
Step 2 => Clay bar
Step 3 => Polisch
Step 4 => Sonax Polymer Netshield to prevent further contaminations

This ^^^

or whats said rjd598

This happened to me last week with 4 laps on the Nurburgring with exhaust reside/dirt. I had to use cleaner wax then applied 2 coats of wax. Went to the ring 2 days ago and this time the dirt/exhaust residue wash off. By the way I have a challenge sport x-pipe and Eisenmann sport exhaust.

Thank your for the tips rjd598, ///M Power-Belgium and OP for posting!

[whats77inaname]

Originally Posted by rjd598

then your plan of action is a good one as mentioned above

We'll see. I did some research on some detail forums, and found recommendations to use Duragloss 501 for this exact problem, so I purchased some and will try it on arrival.

[rjd598]

Originally Posted by whats77inaname

We'll see. I did some research on some detail forums, and found recommendations to use Duragloss 501 for this exact problem, so I purchased some and will try it on arrival.

You should have gone with a pure polish. 501 is an AIO (all-in-one). Nothing wrong with it, but you might need to go to something a little heavier if it doesn't work out. Best of luck and keep us posted.

[whats77inaname]

Originally Posted by rjd598

You should have gone with a pure polish. 501 is an AIO (all-in-one). Nothing wrong with it, but you might need to go to something a little heavier if it doesn't work out. Best of luck and keep us posted.

Works like a boss. You're supposed to wipe, let it haze, then wipe off. This is just the initial wipe. The staining came right off. Keep in mind that I had already washed/clayed this section. You can see the "M" I wrote in the residue.

[MPowerZ32]

Rubbing alcohol. I'm catless and noticed some yellowing on the bumper near the exhaust tips. Rubbing alcohol was able to dissolve the yellow stuff immediately for me. It was completely painless. Worth a shot.

[whats77inaname]

Originally Posted by MPowerZ32

Rubbing alcohol. I'm catless and noticed some yellowing on the bumper near the exhaust tips. Rubbing alcohol was able to dissolve the yellow stuff immediately for me. It was completely painless. Worth a shot.

I tried that prior to the Duragloss. No go, unfortunately.

Pretty pleased with this stuff, though, especially since my trunk was *just* painted a few months ago and it was taking a beating.

[rjd598]

Originally Posted by MPowerZ32

Rubbing alcohol. I'm catless and noticed some yellowing on the bumper near the exhaust tips. Rubbing alcohol was able to dissolve the yellow stuff immediately for me. It was completely painless. Worth a shot.

i hope you sealed up that area afterwards or else it'll just keep coming back.

[rjd598]

Originally Posted by whats77inaname

Works like a boss. You're supposed to wipe, let it haze, then wipe off. This is just the initial wipe. The staining came right off. Keep in mind that I had already washed/clayed this section. You can see the "M" I wrote in the residue.

glad it worked out for you. didn't think an aio would work that well but duragloss does make top notch and consistent products.

edit: i just read more closely and 501 is for intended for marine gelcoats therefore containing stronger abrasives than their 101 which is intended for clearcoats. great info!

[///M Power-Belgium]

Originally Posted by MPowerZ32

Rubbing alcohol. I'm catless and noticed some yellowing on the bumper near the exhaust tips. Rubbing alcohol was able to dissolve the yellow stuff immediately for me. It was completely painless. Worth a shot.

Watch out !
Rubbing with alcohol on dirt can cause swirls...

[whats77inaname]

Originally Posted by rjd598

glad it worked out for you. didn't think an aio would work that well but duragloss does make top notch and consistent products.

edit: i just read more closely and 501 is for intended for marine gelcoats therefore containing stronger abrasives than their 101 which is intended for clearcoats. great info!

Where I got the info:

http://www.autogeekonline.net/forum/...e-gtr-r35.html

[rjd598]

Originally Posted by whats77inaname

Where I got the info:

http://www.autogeekonline.net/forum/...e-gtr-r35.html

this is the seller:

http://www.autogeekonline.net/forum/...oss-501-a.html

[Z K]

The solution is not to run cat-less. The contaminants aren't being filtered and ends up on your car. Most of it is soot from the exhaust. If you let it sit, it will eat into the paint and it will require a repaint. The cleaning methods I've used is washing, claying and polishing the discolored parts. If that doesn't work, you may have let it sit too long and need a repaint.

I ran catless on a car before and my whole rear bumper was discolored next to the exhaust. I put in a cat and repainted my bumper. Didn't have any more problems.

[whats77inaname]

Originally Posted by Z K

The solution is not to run cat-less.

........

Originally Posted by whats77inaname

I'm having the same issue w/my HFC cat setup.

[Z K]

Originally Posted by whats77inaname

........

That is because a HFC is still not as effective at filtering out particulates as a stock cat. It may be better than having no cat but not as good as the stock cat.