alright guys my dad thinks he is right and thought he could put 15W-40 oil in my 2002 wrx TO CLEAN OUT THE ENGINE.
now i knew it was a bad idea but me bieng the kid in the argument he put it in anyway.
all i need is some reasons from other people that this was a bad idea, so i can convince him that this was really A BAD IDEA
and put some royal purple in it before it does any damage.
i've put about 650K in the surup.
Honestly, you'll probably have better luck taking this conversation over to the discussion board on Welcome. The group of experts on that site will probably be of better help to you in coming up with scientific reasons why that may or may not be a bad idea. I just go by the recommended weight (5W-30) in the manual for my car - I believe it's written in raised letters on the oil cap too - so those are my two arguments.
how would using 15w40 clean out the engine?
that oil is too thick, on cold starts it will take too long to flow properly so there will be increased wear on the engine due to improper lubrication until fully warmed up, and once warmed up you will most likely see a drop in gas mileage/performance due to the engine having to work a little bit harder since it has to move through thicker oil
personally i would just pop the drain plug and drain it then refill with a good 5w30, if the filter was changed when the 15w40 was put in then you can probably keep it as it wont yet be dirty but maybe spin it off to drain it too...
chances are your engine wont blow up or anything if you run it until the next oil change, but why take that chance?
i'm not sure what the temperature is like where you are but the colder it is the worse it will be that you are running thick oil...
my boss's 6.6L diesel truck wont start if its colder than -15*C because the oil (15w40) is too thick so the engine doesnt crank over fast enough to start (batteries are new)