How Do I Address Rust Spots Under the Hood? - PeachParts Mercedes-Benz Forum

shertex · #1 02-05-2011, 03:05 PM

Today I noticed for the first time some rust spots under the hood (specifically, on the long metal piece at the top of the engine compartment just above the fans). They look minor enough that what I intend to do is just scrape the spots down to bare metal and paint over it.

Is this "quick and dirty" approach fine?

What kind of paint do I need to get?

In a worst case scenario, if I have to replace this piece, what would it cost?

Thanks!

babymog · #2 02-05-2011, 03:38 PM

If you're talking about the upper radiator support, it's welded in. Is this the 124 or the 126?

Clean it, put a good rust converter on it, if the metal is solid and only a cosmetic repair, no big deal.

leathermang · #3 02-05-2011, 03:40 PM

I pm'd you with secret information...

shertex · #4 02-05-2011, 03:47 PM

Quote:

Originally Posted by babymog

If you're talking about the upper radiator support, it's welded in. Is this the 124 or the 126?

Clean it, put a good rust converter on it, if the metal is solid and only a cosmetic repair, no big deal.

The 124, the 92 300D....I no longer have the 126.

JHZR2 · #5 02-05-2011, 07:59 PM

You have a few options - one would be to grind it to good metal, use an etching zinc paint and then repaint. The other would be to use a por15 or eastwood rust encapsulator With some kind of sealant overtop like amsoil hd metal protector or Eastwood anti rust.

vstech · #6 02-05-2011, 08:05 PM

Quote:

Originally Posted by leathermang

I pm'd you with secret information...

now, that's just rude....

leathermang · #7 02-05-2011, 10:31 PM

Quote:

Originally Posted by vstech

now, that's just rude....

Sense of humor toggled off ? What kind of ' secret info ' could anyone have ?
I thought it was funny.... asked him for more info about his tools and weather where he was...

EDBSO · #8 02-05-2011, 11:31 PM

Sense of humor toggled ON!

I would say "Hello rust..."?

Krown T40 is as good as it gets at preventing rust around here. I would hit it with T40 till better weather arrives.

shertex · #9 02-06-2011, 04:38 AM

Quote:

Originally Posted by leathermang

Sense of humor toggled off ? What kind of ' secret info ' could anyone have ?
I thought it was funny.... asked him for more info about his tools and weather where he was...

vstech, leathermang is just trying to throw you off the scent. In fact, he sent me a secret forumla: you mix this stuff up in your garage....turns into a gas....you leave it in there with the car with the door closed for 12 hours....it seeks and destroys all areas of rust, restores metal to original condition, AND prevents new rust from forming for thirty years....GUARANTEED. You can see why it's secret information....wouldn't want this falling into the hands of BMW owners or something.

vstech · #10 02-06-2011, 07:06 AM

oh, that old stuff. got plenty of that in my mason jars at home.
after you are done mixing it up, be sure and add the sealer, or the extra will settle to the frame and it makes a racket!

JHZR2 · #11 02-06-2011, 08:36 AM

Quote:

Originally Posted by EDBSO

Sense of humor toggled ON!

I would say "Hello rust..."?

Krown T40 is as good as it gets at preventing rust around here. I would hit it with T40 till better weather arrives.

The crown is great stuff, but if the OP is going to fix the spot, nothing should get put on it. More cleaning and hassle is going to have to be done to get ready to treat/coat.

If a topping is put on the rust, IMO the only option then is to grind it to clean metal. Something like krown that creeps will never get out of the rust formation enough to allow a rust stpping product to properly impregnate.

vstech · #12 02-06-2011, 09:24 AM

agreed. krown will stop it where it is, but you'll never be able to paint it again without serious cleaning. not really suitable for painted surfaces, I'd only use that on subframe/suspension stuff. keep the painted surfaces prepped, and treated with encapsulator!

Junkman · #13 02-06-2011, 09:38 AM

FWIW, People fighting rust on old (70s era unibody rust crumbling) Datsun Zs use POR15. Did I mention that a Z is never rust free - not even mine?

leathermang · #14 02-06-2011, 11:11 AM

Quote:

Originally Posted by JHZR2

The crown is great stuff, but if the OP is going to fix the spot, nothing should get put on it. More cleaning and hassle is going to have to be done to get ready to treat/coat.

If a topping is put on the rust, IMO the only option then is to grind it to clean metal. Something like krown that creeps will never get out of the rust formation enough to allow a rust stpping product to properly impregnate.

First, there are plenty of places on our old cars which are not accessible to grinding wheels..
which might indicate the need for sand blasting ..or chemical cleaning...
but grinding would have to take an unnecessary amount of good metal off to be sure it was actually clean... so for our old cars a combo of less brutal ..but also cleaner ( at the metal surface.. not cleaner for the applicator --YOU--- wear protective clothing when called for ) methods is often called for..

If the temperature AND humidity ( meaning some is needed ) are correct then POR15 is a long proven product...
BUT one MUST READ AND FOLLOW THE DIRECTIONS FOR IT TO BE EFFECTIVE...
The harder/tougher the stuff you are applying to the metal the more important it is to do a great job of PREP... getting something like POR15 off an item which it really did not adhere to WELL .. was not doing what you needed it to do... is a REAL serious PROBLEM...

JHZR2 · #15 02-06-2011, 11:28 AM

Quote:

Originally Posted by leathermang

First, there are plenty of places on our old cars which are not accessible to grinding wheels..
which might indicate the need for sand blasting ..or chemical cleaning...
but grinding would have to take an unnecessary amount of good metal off to be sure it was actually clean... so for our old cars a combo of less brutal ..but also cleaner ( at the metal surface.. not cleaner for the applicator --YOU--- wear protective clothing when called for ) methods is often called for..

If the temperature AND humidity ( meaning some is needed ) are correct then POR15 is a long proven product...
BUT one MUST READ AND FOLLOW THE DIRECTIONS FOR IT TO BE EFFECTIVE...
The harder/tougher the stuff you are applying to the metal the more important it is to do a great job of PREP... getting something like POR15 off an item which it really did not adhere to WELL .. was not doing what you needed it to do... is a REAL serious PROBLEM...

If you can't get sandpaper, grinding media, etc in then you may not be able to get the right prep stuff in to be ready for POR.

It is always a case by case basis...

But prep is always key. I'm not keen on taking for chance an isolation/prevention of rust if I can help it. Sometimes this may mean a bit more aggressive practices, though hopefully not...

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