my 87 sdl needs glow plugs still starts but light is out ive tested and 3 2 are bad,my question is how many here have changed out without taking intake manifold off and how many say take it off.ive looked at past threads and seen both opinions-just wanted to get current feedback. how hard is taking manifold off-again ive read the threads but welcome your thoughts and advice

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95 e320,87 sdl,79 300sd