99 s70 turbo oil in water (coolant reservoir)

[prmazdarx7]

this happened 1 time so i had the engine replaced and now it happend again this time the mechanic sayd the oil seal broke and that he is going to use a stronger one.

my question is why put a stronger seal in ? when all you are doing is just
making it worse for the oil presure.(i think)

my guess is that the oil cooler is not working correctly therefore building to much oil presure.

have any of you had this happened and what the remedy was?

thanks in advanced