[W126 Coupe] engine leprosy

[Richard Hogarth]

-----Original Message-----
From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com]
On Behalf Of Doug Gavin
Sent: Friday, June 15, 2007 4:29 PM
To: Mercedes Coupes Mailing Lists
Subject: Re: [W126 Coupe] engine leprosy

Stephen Leslie wrote:

> My 380SEC has been in storage over the winter months and the engine is 

> coated with white powder surface corrosion.  What is the best way to 

> clean this up to look presentable again?   Are there any cleaning 

> solutions anybody can recommend?  

> ------------------------------------------------------------------------


Stephen, 
THE CORROSION MAY BE THE SIGN OF A BIGGER PROBLEM!
	Cleaning the aluminum is one issue, how it got that way may be more
important. 
At first glance, your engine looks like death by salt. On further
examination, (if the pic is accurate) the corrosion is much worse on the
driver's side and on the front of the valve cover closest to the radiator.
Corrosion by salt tends to be worse on the passenger side because of melting
and the crown of the road and the way water spray and puddles occur. 
	This may sound like an unrelated question: If you open the radiator
cap or pull the upper hose, is the fluid level ok and what color is the anti
freeze? 
Consider: If there is even a minor imperceptible head gasket leak; cylinder
to water jacket, a mixture that is highly corrosive to aluminum is created
when the combustion gasses mix with the water. If your anti-freeze is
old,(2+years) it will have lost all of its aluminum protective qualities and
my cause the same problems without a head gasket leak. These corrosive
chemicals will eat through aluminum radiator cores, alum. heater cores and
any internal aluminum engine parts including water jackets in the heads etc.
Also, Once the water jackets corrode internally, water flow will be impeded
and the engine will not cool properly. 
Once the radiator core is thinned or perforated from the corrosive chemicals
with even a pinhole leak that may occur only at certain temperatures, the
anti-freeze with  crud vapor is blown all over the engine by the cooling
fans. 
So - what's going on in your radiator right now? What does the anti-freeze
smell like and what color is it. If it was green, is it tinged brown? If you
used MB antifreeze which is nearly clear, what color is it and what does it
smell like? On engines that use aluminum compression sealing rings and
surfaces in the head gasket composition, catastrophic failure is at some
point inevitable.  Subarus are probably the engine most prone to this type
of problem. Catastrophic failure due to bad anti-freeze is common in
aluminum block engines. (not our cars)

CLEANING: 
Simple way: remove parts, take to chrome shop or powder coater. They will be
chemically dipped or glass beaded, polished not buffed,  then chromed or
powder coated. Way, way simple. 
Home way: 
The valve covers and the air cleaner and many other parts are clear coated.
The clear breaks down over time, first yellowing and developing cracks and
once the aluminum is open to the air and engine gasses, it is vulnerable to
corrosion. 
First you want to get the corrosion 'dust' and grease crap off of the parts
without creating too many scratches in the aluminum. Get a brush with only
non-metallic bristles!!  Go to the supermarket and find the dept. with
sponges, brushes and scuffies. Libman makes some terrific and interesting
brushes with many different shapes which are great for all kinds of car part
cleaning.
	(BTW- Never Ever use a green kitchen scuffie on paint, glass, clear
coat, plastic headlights,  or alum trim! It's 	fast but fatal to those
materials.)
Take the parts off of the car, get 1 gal of either "Purple Stuff" engine
cleaner or Castrol purple engine cleaner. Put the parts in a medium plastic
tub, put the purple juice in a spray bottle, wear rubber or nitrile gloves
and start spraying and scrubbing in all of the nooks and crannies to get the
parts clean of the white powder and whatever other crap is on there. Rinse
with water, dry, repeat if necessary. 
	 If there is still scattered remnants of clear coating on the
corroded engine parts, that stuff will need to be removed with an aluminum
safe paint remover. You can use acetone but the clear will turn to a smeary
goo that can be difficult to remove before the acetone evaporates. If you do
use acetone, wear a respirator. Acetone is toxic when breathed and can cause
liver problems.
	If you are tempted to use an aluminum wheel cleaner or something
like 'Aluminator' that says for bare aluminum only, not for clear coated
wheels,  BE VERY CAREFUL! Those cleaner are only to be used as a
pre-treatment before polishing. And that polishing can be punishing!  Those
cleaners have substances like oxalic acid which will remove all of the
aluminum oxide. What's wrong with that you might ask? The aluminum will be a
dull starch white with absolutely no shine. In that state, it will stain
easily and looks extremely weird and unappealing. After using those cleaners
you will have to then use the elbow grease that Dick suggested. I with Dick
that 'Never Dull' is excellent and it's not messy.  I use 3MT Marine
Aluminum Restorer and Polish on my 17' Grumman Aluminum Canoe.  Noxon,
Mothers Aluminum polish and the other liquids and pastes work well but
getting the residue off can be hell. Never Dull doesn't leave a residue.
Good Luck! and Happy Elbows and finger joints.
-RPH
If you want to see some tips from car restoring pros, clik below:
http://www.classictrucks.com/tech/0705ct_aluminum_polishing/photo_05.html