[W126 Coupe] engine leprosy

[Richard Hogarth]

Stephen, 
Water and antifreeze should not cause the corrosion that you are seeing on
your aluminum parts; if it is actually corrosion. Quite to the contrary,
uncontaminated antifreeze and water should protect the aluminum. I hate to
suggest the possibility of disaster so I would encourage you to look for a
head gasket leak. When the radiator leak is found, look to see if the leak
is in an area where the radiator core is actually 'thinning'. Look at the
inside of the hoses that have been removed after they have dried. Is there a
coating on the inside of the hoses that has any resemblance to the white
powdery stuff on your engine? Take a closer inspection look at the powdery
substance on the valve cover. Does it look like aluminum corrosion or just
something evaporated and dried?
-RPH
axlehead at bellsouth.net
 
From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com]
On Behalf Of Stephen Leslie
Sent: Saturday, June 16, 2007 1:17 AM
To: mbcoupes 
Subject: Re: [W126 Coupe] engine leprosy
 
"Scrubbing Bubbles".  Huh.  Brasso I have used, never heard of Scrubbing
Bubbles!   
 
In the photo, what is not visible is the fact that the rad is presently
removed waiting for a new replacement tomorrow, (hoses and new antifreeze).
The radiator appeared to have a tiny leak somewhere in the lower left corner
and also will be pressure tested tomorrow to confirm where.   Surprise,
surprise, eh?  
 
The antifreeze I removed was MB, clear, about 3 years old.
 
Thanks everybody for the help... really appreciated! 
 
sl





>------- Original Message Follows -------

>From: "Richard Hogarth" 

>To: "'Mercedes Coupes Mailing Lists'" 

>Subject: Re: [W126 Coupe] engine leprosy

>Date: Fri, 15 Jun 2007 17:16:20 -0500

>

>

>

>-----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 corrosi ve

>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&nbs p;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 ext remely 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 restor ing pros, clik below:

>http://www.classictrucks.com/tech/0705ct_aluminum_polishing/photo_05.html

>

>

>The MB Coupes Website!

>W126 SEC Mailing List

>Postings remain property of MB Coupes, L.L.C.

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