Milky oil is almost always a bad head gasket. Why did the head gasket go bad? That is the question. Best to pull the head. Cracks in the head are bad, but not that common. Relax, you most likely are OK. Cracks in the block, are less common. Most of the time the monkey in the wrench as it were, is just bad head bolt to block torque. If the bolts don't get cleaned, and the threads in the block don't get cleaned. Then the torque value is off. A lot. The head is heavy. get some help to lift it off. Straightforward project. Clean off the old gasket, but look close for a compromised area. Most leaks are between cylinders and that is where the water comes from. A wire wheel will clean the head bolts. A Die will clear the threads. A tap in the block will clear the threads and the trick, oil the head bolts before installing. Torque in stages. I start at 30 foot pounds. Then 60, and finish at the book spec. Most 235 engine specs are 90 foot pounds. But use what the book for your engine says. Follow the sequence in the book. It matters. A good straight edge can be had from lots of places. I have found a good carpenters square will work for this. Get the big framing square. They are cheap and straight. Good luck. If the issue is a crack. You will most likely see it on inspection. Head or block. Last engine I worked with had no issues until it had been run and cycled a few times. Then, it got milky oil with a raised oil level. I worried and had the head checked(it was fine) for warpage. It did not overheat. It was 3 bad head bolts. When I dry fit them it took 45 foot pounds to turn them into the block. That would have left only 45 foot pounds to clamp the gasket. Not enough. These engines are tough. Most have been heat cycled a thousand times. Many have had some work done to them. Not all of that work was done well. Catastrophes can happen, but most are just fine.
