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From digest.v7.n102 Wed Aug 13 14:33:17 1997
From: "David R. Deardoff" <>
Date: Wed, 13 Aug 1997 10:49:21 -0600
Subject: Cosmoline Experience RE:Digest 9-something


No problem. Since you're going to check it out I'll give you the steps I followed. And yes I was able to breathe the next day but you'll wonder how after I tell you the combination of solvents I used.

When I bought the car, an '87 325is with 139K on it, the yellow gunk was baked on. I did not like the crap because the intake manifold and valve cover did not have the nice clean aluminium look of the engines I had seen before at shows etc. As I cleaned up the car - not much of a job because it was already almost immaculate, the engine really bugged me. Soap and water did nothing. Being somewhat familiar with various finishing compounds. The stuff looked like aged shellac used to seal the engine compartment. It covered most components - metal or plastic. It looked like it had been applied afterward; after the car had been bought. What idiot would use a finishing varnish?

Since it looked like shellac; I tried denatured alcohol with a fine sanding pad and made little progress so I switched to laquer thinner with the same result. The process took way too much effort and was destructive because of the mild abrasive. The solvents were not dissolving the gunk. At this time I did not know what it was. I thought I would try acetone but didn't have any nor any fingernail polish remover to try to see if this was the solvent. When I went to K-mart - hey a solvent is a solvent; I made a decision to go with paint remover because by now, I was fed up and I wasn't sure about the acetone. Because of the way the yellow/brown stuff looked I sensed it might be epoxy-like so I went with the polyurethane/epoxy paint remover. I used "KS-3 Premium Stripper" for paint, epoxy and polyurethane.

For me, the most prominent components I would clean were the intake manifold and the valve cover. The stripper worked perfectly. It not only cut the cosmoline but lifted it from the surface. I could easily wipe away the stripper with paper towles and a little laquer thinner or alcohol. I would use wood scrapers in tight places. The result was exactly what I wanted with no metal scrape scratches. Since I did not take the parts off the engine when I cleaned them, you have to be really careful not to touch any plastic parts or rubber hoses. I will clean-up the remaining parts as they are removed during maintenace. I have yet to find a solvent that will remove the cosmoline from the plastic parts but since it's not obvious it's not a priority.

I am not dead nor had any hallucinations during this job because I did it in the driveway during the evening - no sun, and the airflow was good.

After all the research, looking through the archives and across the web I could not find out much about cosmoline. Other than it being used by gun-makers as a metal protectant. But yesterday's comment in the digest finally said what it was and why it was applied. Why the dealer never removed it is beyond me. What is "Dealer Prep" anyway?

Since this has become a common question on the digest I will Cc: it to the bmw-digest. I was once a lurker but have used their comments and recommendations to fix everything from a reed-switch for an errant coolant light to replacing the chrome window lock strip.

Tschuss (mit umlaut)

David Deardoff
BMW CCA 143525

                                  ( at   at )
   *************************** oOO-(_)-OOo****************************
   *  David R. Deardoff                         *
   *  1987 325is 144K miles                      Boulder, Colorado   *
   *  BMW CCA #143525         Rechts Fahren                          *
   *    .                                                   /\   /\  *
  • /!\ "Out the 10Base2, Through the Router, Over the / \ / \ *
  • / ! \ Leased line, Off the bridge, Past the Firewall \ / \ / *
  • / ! \ ...Nothing but Net! \/ \/ * */___!___\ -Gary Predmore * ***************************oo==()()==oo****************************
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