My '87 300d puffs white smoke and idles rough at cold startup. I tried the sniff test and couldn't smell sweet antifreeze in the smoke. I just bought a combustion leak test kit with a special fluid for diesels from toolrage. The test was negative for combustion gas in the expansion tank. Here are some observations:
1. It only happens when the car is cold.
2. If I hit the glowplugs twice it doesn't happen. I ohm tested my glowplugs and they tested fine.
3. I ran some lubromoly diesel hitest in my tank and it went away but came back with the next tank.
4. I have no bubbling in my expansion tank with the engine running.
5. My expansion tank doesn't have any black stuff in it.
6. I have replaced my injector nozzles with new bosio's and it made no difference in the smoky rough cold idle
7. When I got the car the turbo was nonfunctional due to a hole corroded in it and an exhaust leak where the manifold and head mate up. The car may have been run like this for a while. Could this have caused overheating and cracked my head?
8. When I replaced the turbo I also removed the exhaust manifold and had it resurfaced since it was warped. I had three broken manifold studs in the head which I had to drill and tap out. Does the warped manifold indicate overheating? Could I have cracked the head when I forced a tap into the stud holes?
9. The car runs kinda hot, 95C even in the dead of winter.
Any bright ideas? I will try the sniff test for antifreeze in the exhaust again tomorrow morning. I am also going to try running some diesel purge and diesel hitest. If this doesn't do it, could it be my glowplugs since hitting them twice eliminates the problem? Can they be bad even if they test fine with an ohmeter on the car? I tested the wires to them as well. Could I have a crack in my head which is too small to allow significant combustion gas in the expansion tank but will still allow some coolant to seep into a combustion chamber overnite? Maybe the crack is open when the engine is cold but as it heats up it closes as the metal of the head expands? Could it be just a bad head gasket? I will update after I try the sniff test and diesel purge. I sure hope it's not the head. My wife is already sick of my car, she calls it the mistress.

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87 300D 162,000 miles: It's not just a car, it's an adventure!