switching oil weight

[jesush91]

Done a lot to this car myself in maintenance issues and gasket such as (oil pan distributor o-ring, etc) leaks but i have 2 left, rear main seal and crank seals that are leaking to the point where i add a quart every month and a half. Did not cure these due to me going back to school today and doing these will deprive me of my much needed car that is my daily driver for 2 days at the least in my garage at home. Switching over from 10-30w to 10-40w this week and wondering if i should flush the crankcase (if so, id like suggestions as to how other people do it) or if i can just empty her crankcase out and drop in the new 10-40w. Been using 10-30w since 101k mi when i got her, now shes at 158,003 mi. Any help is greatly appreciated!

[blb]

No need to flush the crankcase. If you want to switch to 10W40, just drain out the old oil and add the new.

If you live in a cold climate, you may want to wait until warmer weather during the spring to make the switch.

As a matter of fact, contrary to popular belief, you can mix oils of different weights will no ill effect other than the viscosity will be the average of the oils mixed.

[Donald]

Originally Posted by blb

no need to flush the crankcase. If you want to switch to 10w40, just drain out the old oil and add the new.
As a matter of fact, contrary to popular belief, you can mix oils of different weights will no ill effect other than the viscosity will be the average of the oils mixed.

+1

[REN69]

Won't make a difference even if you switch to 20w50... just get the seal replaced, then go to 10w40.