Does anybody know why my v70 would have a squeak in the motor that stops when you pull the oil dipstick?

 

clogged PCV system. when you pull the dipstick it allows the pressure to be released. See if the noise also goes away if you loosen or pop off the oil filler cap

 

Year, mileage and trim level always helps.
What's your APPROXIMATE location?

 

PCV system. This is a very common issue, that is usually diagnosed by removing the oil fill cap or dipstick.

 

Welcome to VF Luke.

Remove to inspect the black tank (PCV). Some times it's not the black box but poor maintenance and oil change that allows the passage in the oil pan to get blocked rendering the PCV system inoperative. The boxes port can get clogged too.

https://www.google.com/search?q=clea...hrome&ie=UTF-8

 

Year and engine?