so i recently cleaned my b18b1 in purple power the other night and the engine came out awesome. i noticed tho that there is corrosion in the coolant jackets inbetween the sleeves and block. purple power said nothing about not using on aluminum so im curious as to if anyone has ran into this before, and what they used to remove it.

 

i dont have any purple power handy at the moment but i always thought it said not to use on aluminum. it will even corrode steel if left to sit to long or if left long enough to evaporate its real bad. double check the label. i am sure my old bottle said not to use on aluminum.
adam

 

it says to test it on a inconspicuous area, which i did with a rag, plus i clean my aluminum rims on my truck with it so i thought nothing of the sort would go wrong with soaking the engine in it. im thinking if i plug the coolant jacket that goes to the water pump i can fill it with carb cleaner, and if that doesn't work, i've heard to use bleach.