Rust on dipstick skew UOA?

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Jun 3, 2002
After completing my oil change and sample collection for annual UOA, I pulled the dipstick and found several areas of "active" rust near the top of the dipstick. I noticed a few small (1/8") spots of surface rust on the last oil change and wiped them clean with an oily rag. This time the rust has "blossomed" into several scaled areas 1/2" long. I will replace the dipstick asap - maybe under warranty. Could this rust skew the UOA somehow? Thanks for any opinions.
Originally posted by doitmyself: This time the rust has "blossomed" into several scaled areas 1/2" long.
I don't think I've ever seen a dipstick with rust on it unless there is moisture present in the crankcase. Especially since it "blossomed" into several 1/2 long areas since your last oil change. I would get that UOA done ASAP and find out what's going on in that engine.
FYI - '05 Caravan with 36K on it. Extreme short trip operation would cause the usual higher moisture than normal. First UOA was excellent. First time I have ever seen rust on dipstick too! It's about 18" long. The top portion stays dry as a bone. No splash or oily fumes deposited. Metal "seems" to have some type of thin coating on the surface,ie.- tinned, or something. My guess is just cheap steel and/or defective manufacturing process. Sample's on it's way to Blackstone. They don't think there will be a problem with the UOA.
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