loubapache is correct, CG-4 is the minimum recommended diesel oil for your vehicle. Mobil 1 is CF-4, I believe. Doubt this has anything to do with your symptom though, as your vehicle did not come from the factory with synthetic. If the glow plug suggestion helps, you most likely have a faulty plug and can test at each of the lines to determine which one needs to be replaced. Did you get the extended Starmark warranty on the vehicle. I assume the new car warranty would have expired last Fall.
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