OM 603

Tilbake til oversikt over Mercedesmotorer

OM 603 er den største i familien av personbilmotorer som består av OM 601, OM 602, og OM 603.

Motorblokken er fremstilt av støpejern, med tørre foringer. Toppen er laget av lettmetall, med overliggende kamaksel. Motoren har to ventiler for hver sylinder, med hydrauliske ventilløftere. Motoren er utstyrt med forkammer, og har glødeplugger. Innsprøytningspumpen er fra Bosch, av typen R-ESP.

Daimler-Benz
Mercedes OM 603.
1986 - 1999
Diesel
Forkammermotor
Motor	OM 603 D 30				OM 603 D 30 A			OM 603 D 35 A
603.xxx	912			931	961	962		970	971	972
Ytelse (HK)	109	110	113	113	150	143	147	136	150	136
Turtall o/min	4600							4000
Dreiemoment (Nm)	185	191			273	267	273	310		305
Byggeår	1985 - 1989	1989 - 1993	1991 - 1993	1990 - 1994	1985 - 1987	1986 - 1988	1988 - 1996	1990 - 1991	1991 - 1996	1992 - 1997
Slagvolum	2996 cm³							3449 cm³
Borring	87 mm							92,4 mm
Slag	84 mm							89 mm
Sylindertall	6
Byggeform	Rekke
Turbo	Nei				Ja
Ladeluftkjøler
Ventilsystem
Kompresjon				22:1
Kjøling	Vannkjølt
Drivstoff	Diesel

OM601 / OM 602 / OM 603 familen av motorer var en serie med rekkemotorer på 4, 5, og 6 sylindre. Motorene ble benyttet av Daimler-Benz i Mercedes-Benz personbiler fra 1984 til 1999.

The 603 engine has a capacity of 2996cc and was an engineering marvel in pre-chamber design and a technological leap forward from the tractor motor like 5 cylinder OM617. Versions 60x.96x and 60x.97x are turbocharged; Versions of the 60x.91x and 60x.92x are naturally aspirated. Only turbocharged models of the 603 series were available to the U.S. market. Only naturally aspirated 601 variants we sold in the US market, The 602 and 606 variant engine of this family available with and without the turbos. The 604 and 605 never made the US market.

The camshafts and injection pump are driven by duplex chain from the crankshaft. A separate single row chain drives the oil pump. The camshaft operated the valves via hydraulic bucket tappets; valve clearance adjustment is automatic.

Fuel injection is indirect. A Bosch PES in-line injection pump is used, with a mechanical governor and vacuum-operated stop control. The pump is lubricated by a connection to the engine oil circulation and the fuel lift pump is mounted on the side of the injection pump. Preheating is by glow plugs with automatic control of preheating time.

The 603 engine was (in)famous for several reasons: The emissions controls imposed in the US market led to the creation of a diesel catalyst, otherwise known as a trap oxidizer. Heat from these trap oxidizers caused failure of the aluminum cylinder heads on the first generation of 603-engined vehicles; debris from the traps could also damage the turbocharger. This first version was sold in the US from 1986 to 1987. Daimler-Benz will remove these traps for free, and if the turbocharger has been determined to be damaged it will also be replaced. Even without the heat from the trap oxidizers, the original pre -14 mold number cylinder heads were weak and if overheated could crack.

In 1990 the 350SD/SDL debuted, using a larger-displacement OM603 engine that had more torque and a lower top o/min. The engine lived on in the w140 chassis after the w126 production ended, as the 300SD or S350. By this time the cylinder head issues had been corrected. These 603.971 engined cars, however, had weak connecting rods that resulted in numerous engine failures. While never formally recalled, Daimler-Benz replaced many engines under warranty, even somewhat after the original warranty term expired (at least for the original owner). Conventional wisdom holds that cars with these engines are generally to be avoided unless accompanied by proof of a factory replacement engine, as the time of free replacement engines is long over.

The 'best' OM603 is the 3.5l factory replacement engine. Second-best is the earlier 3l engine using the later 3.5l cylinder head. (The latter are all that are available as replacement parts from the factory.) Next is the original 3l engine with an uncracked original-style head, which by one account has about a 20% chance of head failure in its service life if the trap oxidizer is removed before damage has been done. Last is the original 3.5l engine, which has a considerably higher incidence of failure. (The failure mode is reputedly that the rods bend a little, resulting in excessive side wear and ovaled cylinders. The only symptom is dramatically increased oil consumption, by which time the block damage is irreversible.)

Versjoner av OM 603

Benyttet i	Årstall	Motorvariant	Effekt i kW (hk)	Dreiemoment i Nm
OM 603.xxx (6-cylinder diesel)
W124 300 D	04/1985 -> 06/1993	603.912	81 (109) @ 4600 o/min (<'89) eller 84 (113) @ 4600 o/min (>'89)	185 @ 2800 o/min (<'89) eller 191 @ 2800 - 3050 o/min
W124 300D Turbo	01/1987 -> 03/1996	603.960 & 603.963 (4Matic)	106 (143) @ 4600 o/min (<'88) eller 108 (147) @ 4600 o/min (>'88)	267 @ 2400 o/min (<'88) eller 273 @ 2400 o/min (>'88)
W124 300TD Turbo	1987	603.960	106 (143) @ 4600 o/min (<'88) eller 108 (147) @ 4600 o/min (>'88)	267 @ 2400 o/min (<'88) eller 273 @ 2400 o/min (>'88)
W126 300SDL	02/1985 -> 09/1987	603.961	110 (148) @ 4600 o/min	273 @ 2400 o/min
W126 350SD/SDL	06/1990 -> 08/1991	603.97x	100 (136) @ 4000 o/min	310 @ 2000 o/min
W140 300SD / S350	09/1991 -> 08/1996	603.97x	111 (150) @ 4000 o/min	310 @ 2000 o/min