Cleaning plastic panels under car.

[ChipperM3]

Before I end up wasting a bunch of money on cleaning products that don’t work, does anyone have a tip for how to clean the coating off these panels?
I soaked them with bug and tar remover then power washed the snot out of them, but that basically did nothing.

[Inizes]

Dry ice

but also, why do you want to remove the coating? It’s factory installed.

[jbfrancis3]

I think he's talking oil residue on the plastic panels, typically from the sieve of a power steering system we have. Over time, the oil converts to a white residue that I haven't found anything suitable to remove it.

[Inizes]

I think he's talking oil residue on the plastic panels, typically from the sieve of a power steering system we have. Over time, the oil converts to a white residue that I haven't found anything suitable to remove it.

Are you referring to this kind of stuff?

https://i.ebayimg.com/images/g/iLUAA...BTo/s-l500.jpg

Because this was applied at the factory..

[ChipperM3]

Yes, that’s the stuff. I know it’s factory, but over the years has chipped off; It just looks crappy.
The pictures I’ve seen of underside refreshes with these cleaned up look good, so while I’m under there...

[jbfrancis3]

Are you referring to this kind of stuff?

https://i.ebayimg.com/images/g/iLUAA...BTo/s-l500.jpg

Because this was applied at the factory..

Get out! The location of the coating made me believe it was leak-related, such as: https://i.ytimg.com/vi/OgksOQxRMBY/maxresdefault.jpg

Never imagined, thanks for clarifying.

[repoman89]

The panels on my M5 don’t have it and they’ve held up fine over the past 20 years. I wonder why they put that ugly coating on the M3?

At one point I went to town with brake cleaner and towels thinking it was some kind of tar ... should have just left it I guess.

[Tbonem3]

Embrace the patina

[Inizes]

I vote embrace!

But if you want to remove it, dry ice will pop it off.

[F1Dryvr]

I had no idea all that crap as factory I figured my previous owner had either driven through something. I had pretty good results with mineral spirits if I remember correctly acetone doesn't work

[Jersey_M3]

Mineral spirits will take it off

[///Mac]

Coincidentally, I did this project last weekend and took a few pics. I had every underpanel off the car as I'm just wrapping up a refresh of damn near everything under the car. All of my panels were coated thick with oil, PS fluid, diff fluid, driveshaft cv joint grease, etc. This is my first time working under this car and it's pretty obvious they hadn't been cleaned since 2002. Took almost an entire day but they came clean eventually.

The panel referenced here https://i.ebayimg.com/images/g/iLUAA...BTo/s-l500.jpg was the only panel with hardened coating that wouldn't come off after soaking in engine degreaser. I applied a heat gun, more degreaser and the edge of a razor blade on this panel. A similar substance is on the subframe and heat shield where the driveshaft meets the diff input flange.

A few pics of the project and results of that panel in particular. For me it was worth the effort to put this car back together with everything clean and looking right.

[Cubieman]

I'd like to do that and I really want to media blast/re-paint the two exhaust crossmember pieces.

Check out this Redish full underside restoration, very nice!

https://youtu.be/EvgmpPpTes4