I would be surprised if that car still had the original glow plugs, 606's eat them.

606's are also famous for having the glow plugs snap off in the head. I would insist that new glow plugs be installed prior to purchase. That way if the head has to come off to extract a broken plug you might get some $$$ out of the seller.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200