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Yellow crud in my expansion tank cap ??

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YOUR RESEARCHYellow crud in my expansion tank cap ??

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POST 1 / ORIGINAL POSTEROriginal post

Short-time 996 owner here . . . When I check my water level, there is a dark yellow substance around the underneath of the cap. Not milkshake-y but more crumbly like dried up Simonize chrome polish. I clean it off every time, but it returns. The first time, I thought "Maybe some oil in the coolant?" The coolant stays clean and clear, nothing amiss with the oil tube or dipstick. Very rarely do I drive the car without reaching normal operating temp. Is this a normal thing? BTW, it's an '02 C2, stick, bone stock.

POST 2Original post

Pics? Sounds like your blue expansion tank cap may need to be replaced. If the number on the cap ends in a number lower then -04 replace it.

POST 3 / ORIGINAL POSTEROriginal post

Just looked at the outside of the cap. It's an "01", so I'll replace it. Then, I'll find a gen-xer to show me how to post a pic. Thank you!

POST 4Original post

Click the Go Advanced button, click Manage Attachments, and all will become clear. Dunno if you can add attachments as a non-member - so there.

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