Oil change without bypass oil filter change

[Donald]

So it will shortly be time to change the oil in my truck. Or at least pull UOA. When I do indeed change the oil what about the roughly 1 qt that is in the bypass filter I am not planning on changing? I assume ifs not good practice to unscrew the filter and dump oil and screw back on the filter?

It would be 1 qt of old out of 14 or 15 qts. So percentage of old is not high.

 

[jeepman3071]

Just leave the bypass filter.

 

[beanoil]

A used oil analysis will tell, but generally, leaving the bypass alone, changing the full flow, and topping off will extend the OCI by 2x.
Pull a sample and see where you are at.

 

[UG_Passat]

You are supposed to change the "full flow" filter in between bypass filter changes.

 

[Donald]

Originally Posted By: UG_Passat
You are supposed to change the "full flow" filter in between bypass filter changes.


Yes, but when to change the oil?

 

[JMJNet]

Don't worry about the oil in the Bypass filter.

 

[Linctex]

Leave the oil in the bypass filter, it isn't hurting anything at all.

 

[UG_Passat]

Originally Posted By: Donald
Originally Posted By: UG_Passat
You are supposed to change the "full flow" filter in between bypass filter changes.


Yes, but when to change the oil?


That's why you do used oil analysis.