Based on all Ive read here in the last couple days, I'm fairly certain I have have a cracked head, but wanted to verify with the forum wisdom.

Its a 1987 300D with 190k mi. and the infamous #14 head. No trap ox.

Symptoms:

1. Thick gray smoke. Bad at idle, hard to know for sure, but seems to be less driving.
2. Engine is LOUD. Much louder than normal. No new frequencies, or off timed noises (pinging, or clanging), just normal sounds with more amplitude. Sounds like a full size diesel truck.
3. Oil pressure pegs at idle.
4. Slight power loss.
5. Slight water loss?? I have only let it run 15 minutes since the "event" but the water looked low in the overflow/reservoir after it cooled. Took a thermos full (16oz) of water to refill it to normal cold level. No evidence of oil in coolant.
6. Oil seems normal. Black, homogeneous. Nothing that seems like water in it. I pondered if it seemed to be higher than normal, hard to say as its parked on a slope...
7. Idles smooth, just more loud.

The "event":

I was driving to work, when someone was driving slow in the fastlane. I punched it to go around, a few seconds into passing I felt a power loss and the engine noise picked up.

Temp stayed put at low 80's, so I continued on to see what happens. As I pulled in to work, the temp was up a bit, mid 80's.

Parked with the engine idling is when first noticed how bad the tailpipe smoke was.

After work I checked the water, and added the 16oz. Didn't know to note if pressure was high on cap removal.

Started up no problem, noticed the oil pressure peg out while idling. That, with the engine noise increase, and smoke I opted to tow it home.

I started it once for 15 seconds to re-position it after the tow truck left it too far from curb.

History:

I am the 3rd owner. PO is a good friend that gave me the car 3 months ago telling me all he knew was wrong. The list was long, but small stuff. Brake lights, flashers, windows, cracked windshields, paint, leather, glowplugs, etc. He had owned it for 10 years and did the minimum to maintain it for the 2 mile commute he had.

In addition to some electrical work, in the last few months I have:

Refilled the AC with R12
replaced the fan clutch
replaced the radiator, t-stat
replaced serpentine belt

Unfortunately, these are all linked with a theme of getting warm to hot. The AC use accentuated the temp gain when going up hills or when sitting in traffic (95-100) This prompted the fan clutch change. Removing the stripped 8mm hex bolt was such an ordeal, I opted to only tighten the replacement T-55 bolt (no locktite). It was fine for a day, but came loose when I punched it (hmm a theme). The fan blade flew off and punctured the radiator. In the 2-3 minutes between hearing the noise of what later turned out to be the fan, and being able to pull off the road, temp got into the red.

In the hopes that the in red time was small enough to not make the head gasket fail, and knowing the radiator replacement was relatively easy, I did so.
(I used blue loctite on the new fan clutch bolt BTW. Single bolt, spinning with positive and negative torques. I should have known better than to heed the "just torque it down" proponents...)

I had been driving it somewhat gingerly for a week before the the "event" happened with no fluid mixing, so my concerns about damaging the head gasket were abating...


I have not landed on whether or not to fix it. If its a cracked head, i wont. If its "just" the gasket I might. The gasket seems like a pretty big task on its own, and has some uncertainty it will fix the issues, particularly with this #14 head. I'm also kind cranky from the poor driving to wrenching ratio of late (albeit somewhat self inflicted because of a few drops of loctite). But it sure drives nice when it does!

The head seem like too much. the cost of a head, the trouble to find one, the modification for the injectors, the time to do it all.

So do I have a gasket issue or a head issue? Can you tell from the symptoms? It there a relatively easy test to verify either way?