I've searched the forum but no luck finding the answer to my question...

What is the significance of the "markings" left by mechanics on various components in the engine compartment. (e.g. a yellow marking on the upper radiator hose where it meets the housing) There are various other marks of various colors elsewhere, usually on a fastener or at a connecting junction.

What do these mean and do the different colors signify anything?

Many thanks in advance!

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Brian Bach
1991 300D 2.5 Turbo

Are you sure they were left by mechanics and not by the factory?

My guess is that these marks are used by inspectors in the manufacturing process as a check or quality control during assembly.

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95 E320 Cabriolet, 159K

Kestas,

I never thought about factory markings. I just assumed that since they were still clearly legible, they must fairly recent. Your answer makes sense, though.

Thanks for the reply.

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Brian Bach
1991 300D 2.5 Turbo

In some cases I believe there's a yellow dab of paint so the dealer can tell if a component's been touched. One of the bolts to be loosened to adjust injection pump timing in Diesel engines usually has a dab of paint.

Sixto
91 300SE
87 300SDL
83 300SD