Peter Frederick wrote:
The 603 is a notorious white smoker cold. Run the GP ten seconds or so extra after the lamp goes out and this will help. I let mine idle thirty seconds or so before putting it in gear, and drive very slowly until it stops rattling when starting off cold (on the assumption that letting the piston crowns heat up slowly is a good idea).
Peter correctly notes that the OM603.96 engine is notorious for white smoke in cold weather. 602 engines are not nearly as bad and 601 engine are considerably better yet than either of their bigger brothers about NOT smoking.
I believe there are several factors that contribute to this, but the main one is that the exactly the same power source and path (the resistance of the wiring to the relay) supply power to 4, 5 and 6 plow plugs. I suspect that the 6 plugs in the 603 engine simply don't get as hot as fast as the 4 plugs in a 601 engine (that draws only 66% of the current) or the 5 plugs in a 602 engine (that draws 83% of the current of a 603). There is also the fact that exactly the same starter and battery is turning these 4, 5 and 6 cylinder engines and the load on starter turning the 603 is greater than the load on the 602 or 601 engine so the 603 engine WILL turn over somewhat more slowly!
With all of these engines, as the glow plug relay ages, the duration before the light shuts off declines as the capacitor in the timing circuit ages. This is NOT a linear phenomena and seldom appears in a regularly driven car before it reaches 12-15 years. In cars that are NOT driven for a period of time (months or years) the delay may be sudden and quite marked in even a relatively new car or even a car with a new relay. The failure usually occurs when the capacitor is NOT energized regularly (daily or weekly) and can happen to a NEW relay that sits on the dealer's shelf for months or years before being put into service. Glow plug relays (new or used) do NOT have a long shelf life.
Marshall -- Marshall Booth Ph.D. Ass't Prof. (ret.) Univ of Pittsburgh School of Medicine Department of Pharmacology 1300 BST Pittsburgh PA 15261 USA [EMAIL PROTECTED]
