Were the valve guides installed MB OEM? I do not remember the specific issue Dave M. (GSXR) brought up with the aftermarket valve guides, it may have just been an installation issue, but I was warned not to use anything but MB OEM guides.

As an aside, I would have bet money that you could not change the glow plugs on a 603 turbo motor without pulling the manifold, but I am stuborn enough that I proved myself wrong on this one. (I am not disputing that it may very well be easier and even possibly quicker to change the 6 gp's out by first removing the manifold.) I had some grit/road grime on my head that I did not wish to risk getting into the intake, and frankly I did not wish to use up a set of gaskets. Along with a few other minor projects, fixing vacum lines, pulling the glow plug relay, etc. it took me three hours start to finish. (I wish I had gone with another set of Beru plugs, very disappointed in the plastic collar on the Bosch plugs.)

I removed the washer resevoir, disconnected the i/b push pull throttle rod near the #3 & 4 GP's, and unbolted the black plastic throttle mount bracket that is bolted to the manifold. I primarily used 1/4inch drive tools, with a universal sockets, wobble drives, etc. both for the wire leads, and the glow plugs. I did not need to use penetrating oil, as my glow plugs came out fairly easily, but I would highly advise that if you use universal sockets, wobble drives, etc. that you soak the GPs with something along the lines of Mouse Milk or Kroil 24hrs before you start the project.

With the mileage you have on your car, the following should not apply, but I will share it for those who might find it of use. I run my oil between the bottom of the dipstick and the mid point of the dipstick, and at 229,000 miles it does not seem to burn a drop of oil from 0-5000 miles. On occasion, I do see some minor smoke at start up, which I attribute to the injectors needing a good cleaning, and/or rebuild, as the engine always seems to run a tad rough on these occasions that the smoke is present. If your head is starting to let go, you might start to see some smoke on start up, probably mixed with steam, it will be whiter and very whispy, rather then trailing off and disapating, the smoke trail will have a sharp cut off when the moisture returns to ambient temps. (Hope that makes sense.)

Did the 1987 USofA market 300D's come from the factory with a block heater installed on the 603 motors? If so, where is it located? (Not that I need one in Texas, but it would be nice for the 10 days of winter we get. LOL.) Thanks, Mack