Undercarriage protective spray paint

[Runner27]

When I bought my 4Runner in June 2011, I lifted the car up to check the undercarriage for rust and spray the underside with rustoleum high heat enamel. I am planning on doing the same thing this upcoming summer. My question is what is the best spray paint that you guys recommend for the job?

I live in Pa and we have a lot of snow and salt on the road during winter time.

Thanks.

 

[Zuke]

Use an undercoating spray. 3M and Dupicolor make decent ones Spray paint will wash away in water.

 

[jimithing]

Have you looked into POR? It's a little more permanent than some of the sprays. Here's some info and pictures:

http://www.toyota-4runner.org/4th-gen-t4rs/28922-under-body-touch-up-rust.html

http://www.toyota-4runner.org/4th-gen-t4rs/97178-rust-lower-parts-07-4runner-should-use-por15.html

 

[diamondplate]

you'll have to powerwash and try to scrub off all the loose stuff prior to painting. I have had great luck with spray on bedliner for the underside of my truck.

I've heard good things about POR, but I have not used it.

 

[mrrab]

Have you looked into POR? It's a little more permanent than some of the sprays. Here's some info and pictures:

http://www.toyota-4runner.org/4th-gen-t4rs/28922-under-body-touch-up-rust.html

http://www.toyota-4runner.org/4th-gen-t4rs/97178-rust-lower-parts-07-4runner-should-use-por15.html

Plan on doing the same to my 4Runner this spring. Think it will be worth it in the long run.

 

[Dougtoms01]

+1 on the bed liner spray paint. It seems to hold up well, is not tar like and will pop off if rust re-develops underneath. It's fairly quick and easy and you can reapply if needed on an annual basis. You should inspect and service your undercarriage annually anyways. I've been using this on my vehicles for 10 years and find it easy enough that I keep up the undercarriage service. Usually 2 cans will do the whole vehicle, about $15-$20. I got this method from a forum on restoring old cars. That's what they were using and the fact that it's durable, but pops off where rust returns I thought was a good indicator for me.

 

[jdkilroy]

You might consider checking out a product called "Ospho."

Active ingredient is phosphoric acid. when applied directly to rust it reacts turning the iron oxide (rust) to iron phosphate which is inert and will go a long way toward preventing/slowing further rust of treated surfaces.

We used to use it all the time on the ships to prep any steel before painting.

It never used to be availble for consumers but I recently found it at Jamestown Distributers. (jamestowndistributors.com) It ain't cheap but it goes a long way and it really works. It is similar to the old "Naval Jelly" but much cheaper and more effective because it is quite thin and has added surfactants that allow it to wick into every nook and cranny in the rust.

You need eye protection when you use it and don't wear any clothes you are fond of...

Jon