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Discolored Piston

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KVH

KVH

Obi Wan
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I'm looking up at the underside of my 4 pistons, oil pan removed. Any idea why piston number four would look brownish yellow up there on the underside?

I know that sounds strange, but that's what I'm seeing. thx
 
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What do the others look like? Just guess, something causing a very different combustion temperature going on. Too lean, too rich, etc. Do you know that they were all the same at some time before?
 
I'm surprised the other three don't have some discoloration. Either #4 gets more oil under it, or it's running a bit hotter than the other three. How do the plugs look?

John
 
All that hard acceleration throws the oil up and back, out of the sump, against the underside of #4 piston. Whatreya, new?
 
Because you can't see the other three as well?
 
I believe there are cases where #4 does get hotter due to blockage in the rear coolant passages. I know I sucked some stuff out of there one time when I had the head off (shop vac with skinny tube -- sort of TR liposuction).
 
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