surface shield makes tar undercoating flake off over night. it comes off in huge sheets. Fluid film was on there for a year, and the undercoating was intact.

surface shield is supposed to be better in the wheel wells because it is tougher

fluid film flows+recovers better so it is said to be better on the main chassis

 

What is surface shield? And how does it make the undercoating peel off?

 

pb blaster surface shield is a lanolin based coating that inhibits rust. the tar undercoating softened and came off in sheets in some areas, other areas didn't seem to be affected.

 

I went out and bought a can of surface shield to test it on a car I have, that has some undercoating overspray on the inner fenders. Left it on over night and took the car to the high pressure car wash today. Didn't do didley on my old undercoating. I wonder if some sections on your car wasn't adhered correctly. It was worth a try.

 

An ancient car like that, and I bought it when it was 7 years old. No doubt it has been undercoated with many products. And like I said , some areas were unaffected. The exposed paint looked brand new

 

Interesting. First I've heard of it. My car doesn't have much undercoating and I have never done it. So it might be a quick way to clean it up and renew the underside. Thanks.

 

as said before in the public domain , the problem with the tar under coating is by the time you can tell that corrosive salt water has been trapped under it, the metal is GONE. Or you can test it with a wire brush every year, and hope it knocks the compromised tar coating off.

before the first winter experienced in NJ, I did the tar undercoating. And been maintaining it every year since, using different brands.