A Nissan Pathfinder 2005 has white foam on it's oils dipstick. Is it repairable? There is no black smoke.?

whilst i agree with grandpa jack about short use .remove oil filler cap ..start engine ..whitish chuffing smoke ?..if yes ..crankcase compression ..worn engine ..some mixture is getting behind rings .pushed downwards into sump ..on next stroke its forced upwards ...that white stuff is called mayonnaise ..mixture of fuel/oil/water ..

Take a look at your oil.  Does it look OK?  Does the car's temp gauge act normally?  If so you're probably OK.

Grandpa Jack gave you the correct answer. 

When you see white smoke coming from your exhaust you have a definite problem. 

If your coolant level is not dropping (or rising) then there's probably nothing to worry about.  Short trips where the engine isn't allowed to reach and maintain full operating temperature can cause condensation that doesn't get a chance to fully burn off which then makes the oil look a little "milky".  If the coolant level is changing over time that's when you've got a problem with coolant and oil mixing.

sounds like a leaking head gasket or a leaking intake manifold gasket ..............