Exhaust manifold rust removal - PeachParts Mercedes-Benz Forum

#1 09-30-2004, 03:49 PM

I recently bought an 86 300E and am interested in making the engine look decent. However, there is a large amount of rust on the exhaust manifold which detracts from this. I am wondering what a good, cheap way to clean this off would be. I was thinking perhaps CLR and a brush? Any responses would be appreciated.

manny · #2 09-30-2004, 05:13 PM

How about a brass wirebrush on the end of a drill ?

#3 10-01-2004, 02:37 AM

Thank you. Would you say its hard to damage it or is it pretty resiliant?

MTI · #4 10-01-2004, 03:28 PM

The manifold is cast iron, like those lodge frying pans, so don't worry about it being "delicate." Griot's Garage sells brush on (foam brush) high temp paints in two or three colors than can be applied with the manifold on the car (can't paint the underside that you can't see anyway). They do recommend knocking off rust flaking or scaling with a wire brush before application.

artpb · #5 10-06-2004, 12:20 AM

Permatex Naval Jelly removes rust from manifolds. Apply carefully in small amounts, let sit a few minutes and then agitate with a small stiff brush. Rinse with plenty of water.

Do small sections at a time and repeat if necessary.

Don't get this stuff on anything else, or else!

donbryce · #6 10-06-2004, 09:47 AM

Eastwood sells a great brush-on (or spray on) manifold coating that won't burn off, although after about 2 years, some rust spots may appear. I say this from personal experience having smoothed out a pair of rams-horn manifolds for my 350 small block street rod engine. It must be used within a certain time frame (shelf life of 6 months if I recall), and can be had grey or black.
If you just clean off the rust and leave it at that, it will re-rust in no time flat. And forget most of those spray can coatings, except for maybe some high end orange or silver header coatings sold by performance shops. Most will burn off in a short time too. I don't know about the staying power of the Groits product, so maybe it works too, but I know the Eastwood stuff works.

pmari · #7 10-22-2004, 06:11 PM

(Newbie here waiting to get my Diesel Benz)

First get rid of the rust either mechanically, chemically or elecrtically.

http://www.metalwebnews.com/howto/rust/rust.html

"Rust is really Fe2O3, a reddish form of iron oxide. Iron has another oxide, Fe3O4, which is sometimes called black oxide, black rust, or hammerscale. Black oxide is a good protection for steel. Like aluminum oxide, black oxide molecules are the same size as iron molecules, so black oxide does not grow or flake. Black oxide is true gun bluing and the oxide found on some drill bits. Black oxide is also seen on iron and steel that has been hot-worked. "

Once cleaned (or converted) some stove black paste or Hi temp paint (stove bright or header paint) could be used.

Iwannanutherdiesel
(04 VW TDI Passat)

newkid · #8 10-26-2004, 08:54 PM

Donbryce, where can I buy Eastwood coating?

MS Fowler · #9 10-27-2004, 06:34 AM

Eastwood is well known, and their products are well respected among auto restorers. I know they have a web site. You can order there, or by phone.

artpb · #10 10-27-2004, 08:11 AM

If you just want your car to look better then go ahead and remove the rust and recoat the iron parts. If you show your car then remove the rust and stop there.

dieseldiehard · #11 10-27-2004, 06:36 PM

I'd say if you show your car (formally or to friends) then you send the part to Jet Hot and let them silver coat it, it will look great foreverafter.
Those coatings you buy and spray or pain on are real crappy, they never look professional and can come off (sooner or later, usually sooner!)
Check out Jet Hot Coatings tel 1-800-432-3379 Cost was about $100 for the manifold in my W124 pictured below. Including bead blasting polishing where necessary to make it look super great (before Jet Hot it looked really awful!)
http://www.jet-hot.com/pages/whyjethot.html

dieseldiehard · #12 10-27-2004, 06:42 PM

gsxr posted this photo of my manifold before it was installed in my car. beautiful, no?
http://www.meimann.com/images/mercedes/OM603_intake/exhaust_JetHot2.jpg

donbryce · #13 10-28-2004, 08:29 AM

Quote:

Originally Posted by newkid

Donbryce, where can I buy Eastwood coating?

http://www.eastwoodco.com/

Kestas · #14 11-04-2004, 11:17 AM

How about just sandblasting them? I typically sandblast anything I restore. It removes ALL rust, leaving healthy metal for you to treat and paint with the topping of your choice. I would never recommend painting over rusty metal. Most rust is a hydrated form of corrosion products, and the water would continue to give you problems in the form of bubbling.

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