[Mr. Merk]

Originally Posted by ant7

I mentioned this in another thread recently, but worth mentioning it again here, there is a rare possibility with cars using vacuum assisted brake boosters, that brake fluid can get into the engine via the inlet manifold if there is an issue with the brake booster and master cylinder, again just a thought, and easy to check, just remove the vacuum pipe from the brake booster, and plug the pipe so there is no leak to the inlet manifold, see if the smoke clears.
Ant.

I had a client years ago with a GMC Sierra who ran into this exact issue. They couldn’t figure out where the brake fluid was disappearing to and just kept topping it off. Eventually the engine failed because it had been consuming so much brake fluid.