The underside of my car is covered with a coating of oil and dust from over the years. Think prior owner repaired oil pan seal that was leaking oil on underside. Also was a little bit of oil around pan area after I bough it so I think under body was getting sprayed for a long time. I tried cleaning a small area under the driver seat (see pic) with kerosene in a spray bottle and rags. The little spot shown took a while as the buildup is thick and dry in areas.

Is it worth the effort to clean entire underside? Initially I thought it wouldn't take too long and would allow me to see any rust spots. From cleaning that little spot, there appears to be small holes all over the bottom that are plugged. I'm thinking that these should be cleared to allow for drainage? Also, thinking that it might be best to leave coating on since it appeared to protect underside pretty well all these years. Thoughts?

 

its up to you. oil is, however, a good rust inhibitor....

 

cleaning dirt & grime , hell yes . cleaning/removing undercoating , no . i have a inside & outside lift . the outside lift does a lot of low pressure washing of underside of vehicles . if you have access to one use it . you will be glad you did . i have found dirt/oil/grime/crud in places that i didn't even know were places . good luck .

 

I am a little late to this thread - but I just wanted to let you know - that is not a buildup of oil and dirt - your car was undercoated. It does a nice job of preserving the metal, but as you found out, removal is a pain.

 

depends if it bothers you...i agree that oil is a good rust inhibitor...i hope to paint my underside with por15 on of these days

 

82tarecaro is right. Whats under that car looks more like a prtective undercoat then any kind of buildup. It´s to evenly spread to be accidental.

Some old fashioned methods of undercoating the carriage of a car is to use oil and tar based products.

Modern protective paints do a better job at long time protection because they do not scrape away as easily.

As you found out, it´s a bit of work to remove the stuff. If you decide to do, coating the underside of the car with POR15 or bedliner will give you a good finish that will last quite a while.

 

Are you sure that it is a factory undercoating? Either way, I am going to leave it alone. Too much work to remove and it seems to be protecting the underbody anyways.

 

It must be. I had the same thing under my car and on the floor pans I took out of a donor car. A wire brush on the end of a grinder makes quick work of it, but it does create a mess.

 

It is more likely a dealer applied undercoating. The factory undercoating was limited to the wheel wells and a few spots on the unibody frame rails under the hood.

 

Not factory.
Either dealer or owner applied that.

It took me only 8 hours to remove from my car.
I then stupidly enough pasted something similar under the car so I´ll be removing that as well and conserve the car using Brantho Korrux 3 in 1 which is a German product and therefor cheaper for me to obtain then POR15 or bedliner.

Serves the same purpose though. Long time conservation and rust arrest / prevention

 

I vote no on the sealing. Its almost IMPOSSIBLE to get ALL of the dirt, grime, salt, etc off a car - The sealer will more than likely keep anything that you missed IN, keeping it from being rinsed OUT. Just my 0.02....

 

Maybe just a good cleaning with a pressure washer would get it looking better. And doesn't it controll some sound deadning qualitys. My t/a has under coating under it. Im going to clean it and atleast touch up the wheel wells for better looks and also some of the areas that have questionable spots after inspection for damage and rust.