First of all, the vehicle in question is a 1981 240D. I have a good cylinder head with valves waiting to be installed. The assumption is that I have a cracked head. However, I want to be sure before I tear everything apart.

1. The car consistently starts on the first tick of the starter, no matter how long it sat, how cold it is, or how weak the battery gets.

2. The car is 'fast' and revs smoothly.

3. The engine sounds healthy, the oil cap bounces ever so slightly, and almost no smoke is leaving the valve cover when the cap is off.

4. All filters are clean.

5. I drained the oil and found no coolant. I drained the coolant and found no oil.

6. The radiator hoses do not pressurize until it reaches operating temp of 80 C and I see no exhaust in the radiator.

7. When the car hits 80 C, I get a ton of white, sweet smelling smoke and the engine starts to struggle for a few seconds before stalling.

8. Brand new oil pump and full oil pressure at start up and idle. I looked online and didn't find a procedure for bleeding the oil pump. I just installed it and got full pressure right away.

I lose no perceptible level of coolant, and the engine cannot idle. I can drive it this way slowly, but the car loses almost all power and stalls when dropping back to idle.

My current view is that a crack has developed in the head, allowing some coolant into at least one cylinder. The coolant doesn't seem to reach the oil, apparently burning off as steam at a quick pace. I think if the car didn't stall, I would be finding coolant in the oil. I am also surmising that the coolant is entering the cylinder faster than the fuel from the injectors. The IP has never been timed to my knowledge and the chain shows 6 degrees of stretch, thus the fueling is retarded and the coolant is steady, leading to the stalling.

My fear is that I will do all this work replacing the head and it won't help. I am downright dreading the job because I have three other cars I'm sorting out now and keep pushing this one back.

My question is, would there be any other reason for a seemingly healthy motor to behave this way?

Part of me wants to believe I'm missing something simple here, or trying to make it more complicated than it is.