Welcome back:
That is a concern. Can you upload a pic of what you are seeing? Also, I'm not supposed to recommend any products because then people feel we are getting a kick back and that isn't the case. However, any of the original brands all work well. Products from Prestone, Blue Devil, Gunk and so on are all good.
Let me know. Also, if possible, upload a pic. I'm concerned there is oil getting by a head gasket. Take a look through this link to see if anything mirrors what you are seeing. Also, a bad head gasket can cause temperature fluctuations.
https://www.2carpros.com/articles/head-gasket-blown-test
Take care,
Joe
Sunday, October 13th, 2019 AT 7:36 PM