Oil Undercoating for winter? - PeachParts Mercedes-Benz Forum

Ya Mar · #1 10-20-2010, 02:22 AM

This spring my friend and I repaired a lot of rust on my 300D. New rocker panels, repairs around the wheel wells, etc.

Now I'm wondering what I should do to protect it for winter driving.

The car has 255k miles and I'm certainly hoping it has a lot of life left in it. I'm wondering if I should start oil undercoating? I'm concerned it will make things messier when I'm working on the car....

What have other MB drives done about preventing rust? Is oil undercoating recommended?

Also, how are these cars on winter roads? I live up in Vermont and I'm wondering how it will do if I put studded snow tires on it. Is it even worth it? Will it still fishtail like crazy?

The car seems so heavy it might be okay.

Stretch · #2 10-20-2010, 03:17 AM

Old engine oil as an undercoat is as you say messy but I think coupled with regular inspections is probably as good an undercoating as anything you pay money for - well all of the stuff that is sold over here in Europe anyway. The main benefit of old engine oil as I see it is that you can quite easily remove it if you need to...

Other possibilities are waxoyl and Dinitrol

Check out this recent thread:-

Reviews on this rust prevention product

barry123400 · #3 10-20-2010, 10:17 AM

Mix in some cheap grease with the oil. I would use a hotplate with a pot of water to immerse my schultz gun container in. Thats a cheap gun for spraying coatings on rocker panels etc normally.

Heat the mix up to a sprayable consistancy. The grease component helps it hang on. Drill holes for access into closed areas like the rocker panels. One half inch plastic sealing plugs are available at most auto parts places for a dime apiece.

The mix creeps into all the nearby areas. I have a very expensive hydralic grease sprayer. Not practical for random self use. This is just a cheap way to achieve a simular end result.

You are right though in Vermont like here the road salt will eat these older mercedes bodies alive. Rusting was their major weak point and undercoating with petroleum products is the best defence I ever found. Existing rust under the factory undercoating of course nothing can totally protect. The oil grease mixture does seal the enterance points of new moisture Though. Do not waste your time with any tar based undercoatings. They can actually make the problem worse. All paint work should be done before application. It really does work if you get the mix on in a concientious fashion. Do not worry about working in a greasy area. The stuff can be steamed off.

Or another way to look at it is. Without good protection using the car in the winter in your location. You will have nothing left to work on anyways. These are unibodies. It is also believed that a good run on a dry dusty non paved road adds dust to the mixture to firm it up a little more where totally exposed. It also helps by reducing the corrosion rate on fuel and brake lines substantially.

vstech · #4 10-20-2010, 10:22 AM

por-15 the repaired sections, and rust will not return. IF DONE CORRECTLY!

okyoureabeast · #5 10-20-2010, 10:24 AM

My car has been rust proofing the underside for years!

300sdToronto · #6 10-20-2010, 11:44 AM

I've used a Canadian silicon based oil product called Rustcheck. Have used it on many vehicles including both of my Mercedes with great success. You can get it in bulk cans and aerosol spray cans at Canadian Tire, if you want to slip across the border from Vermont....

pawoSD · #7 10-20-2010, 11:49 AM

Quote:

Originally Posted by vstech

por-15 the repaired sections, and rust will not return. IF DONE CORRECTLY!

Thats what you think! Ever been to MI?

My P/S pump started to leak about 1.5 years ago, and I let it leak, because it coats the entire underside of the car and engine compartment with p/s fluid, which is an amazing rust protection.....no rust under my car since!

Marvelicious · #8 10-20-2010, 12:05 PM

Quote:

Originally Posted by okyoureabeast

My car has been rust proofing the underside for years!

...and if you don't have enough oil leaks on your own, leave your dipstick up about a half inch or so above that o-ring. Don't ask me how I know.

compu_85 · #9 10-20-2010, 01:11 PM

Quote:

Originally Posted by pawoSD

Thats what you think! Ever been to MI?

My P/S pump started to leak about 1.5 years ago, and I let it leak, because it coats the entire underside of the car and engine compartment with p/s fluid, which is an amazing rust protection.....no rust under my car since!

My 91 ECOdiesel had the same feature. Couple that with a leaking valve cover gasket and everything was nice and rustproof. I cleaned a lot of the gook off to reveal sparkling shiny aluminum! Bad move though... one drive through the salt and it was all corroded.

Yes, Michigan winters are able to rust aluminum

-Jason

DieselPaul · #10 10-20-2010, 02:54 PM

My plan was to put my car on the lift and do a little POR15'ing.

I also wire wheeled my rockers, cleaned them up, wiped them down in alcohol, primed and painted them and I put grease up in the jack points.

MBeige · #11 10-20-2010, 03:10 PM

Now I'm debating on whether or not to fix the leaking oil filter housing gasket

Then again here in southern CA there isn't much in the way of snow or salt on the road.

barry123400 · #12 10-20-2010, 07:29 PM

Quote:

Originally Posted by DieselPaul

My plan was to put my car on the lift and do a little POR15'ing.

I also wire wheeled my rockers, cleaned them up, wiped them down in alcohol, primed and painted them and I put grease up in the jack points.

The rockers need protection from the inside. Holes have to be drilled to get petroleum material in there. Inside frames and the rear suspension components as well. At least most of those are managable with no holes to drill.

Ya Mar · #13 10-20-2010, 08:05 PM

Hi Everyone,

My car also has the amazing ability to oil undercoat itself, but it's mostly in the engine compartment.

I think I will go ahead and get it oil undercoated as I want it to last for a lonnnng time.

I just discovered today that it has a factory rebuilt engine from Mercedes. The 255k miles are on the body, no idea what is on the engine.

However, when I unscrew the oil cap with the engine running it barely moves. The engine idles wonderfully.