Water in pan after a week of sitting with no prior issues

[98k2500]

Hello,

Vehicle 1989 K2500 6.2L J code.

So I have water in my oil pan suddenly. I parked my car for a week to remove 8 swollen plugs. Prior to this I had driven the car up and down the road and took it for one long drive to move it from one property to another (>30 miles highway driving). It also sat in a field for over a decade without any water getting into the oil. I haven't had any issues with water in the oil.

I haven't had any overheating issues. Although I haven't taken it for a drive yet. I haven't done a compression test. Just based on cranking there is an even gallop and the engine sounds healthy, I am in the process of moving so I can't find any of my tools, I will be renting a diesel compression tester this weekend. There is a good bit of milk shake. I change the oil once and when I started running the engine again I got milk shake again. I still haven't driven anywhere just idle the car.

I don't have the belt hooked up and the water pump pulley is off. I have just been idling it for short periods of time.

I did wash down the entire under hood interior with a garden hose, I wouldn't expect to make it passed the rings, I wasn't sure if there was another entry point? There is the back of the engine where a distributor is on a gas engine, where I understand a mechanical vacuum pump is driven?

It has all of the symptoms of a head gasket, but it just doesn't make sense to me how it could be. I want to be certain before I tear the heads off.

I have lost a significant amount of coolant during the glow plug removal but I also disconnect the heater core to get the back plug / injector and I just let the hoses dangle and the coolant drain during the process.

I also had to remove a bunch of things and put them back such as the dip stick. Although I believe as of (after) last time I change the oil, it is secured with the 7mm bolt into place. During the week while it was sitting the dip stick pulled out and it was raining consistently, heavily, every day. The vehicle is parked outside, not covered.