OM601 OM602 connecting rod A6010304620 – buying guide W124 W201
Anyone overhauling a Mercedes prechamber diesel of the 601 family – whether in the W124 200 D, the W201 190 D 2.5, the W202 C 200 Diesel or the G-Class 300 GD – quickly arrives at the question once the crank assembly is open: is the connecting rod still usable, and which number do I need? New original connecting rods for these engines are hardly available any more, and the numbers differ in only one digit. This buying guide shows which findings call for replacement, what you need to look for when buying, and which vehicles the A 601 030 46 20 is documented for.
How do you recognize wear or damage?
The connecting rod joins the piston to the crankshaft. The split big end runs on connecting rod bearing shells on the crank pin, and the small end takes the piston pin via a bronze bushing. Whether a connecting rod needs replacing can only be judged with the engine removed or the oil pan off.
| Finding | Meaning |
|---|---|
| Bearing shells at the big end scored or discolored blue | Indication of oil starvation or bearing failure. Have the big end checked for roundness and signs of wear – if it is damaged, replace the connecting rod. |
| Noticeable play of the piston pin in the bushing of the small end | Bushing worn out. Depending on the findings it can be renewed; if the eye itself is damaged, replacing the connecting rod is the solution. |
| Connecting rod bent or twisted after engine damage | Do not reuse. A distorted connecting rod loads piston, pin and bearings unevenly. |
| Connecting rod from a different engine with a differing number | Do not install without checking: weight class and stroke variant must match the engine (see buying points below). |
| Blue smoke and increased oil consumption without knocking noise | Usually not a connecting rod issue, but hardened valve stem seals – see OM601 valve stem seal guide |
| Diesel jerks when lifting off the throttle | Not crank assembly damage, but often the linkage damper – see W124/W201 linkage damper guide |
Causes
The connecting rod itself is a robust, forged component. After decades and high mileage it usually does not fail on its own, but as a consequence of other damage: oil starvation or overly long oil change intervals damage the bearing points, a seized connecting rod bearing can take the big end with it, and engine damage can deform the connecting rod. During an overhaul, often only a single connecting rod is needed – and that is exactly when the right number is crucial.
What to look for when buying
- Compare the part number 1:1: This connecting rod carries the number 601 030 46 20 (A6010304620). The similar number 601 030 47 20 designates a different connecting rod and is not interchangeable.
- Check the stroke variant: The 601 030 46 20 is intended for the engine variants with 84 mm stroke. The long-stroke versions with 92,4 mm stroke (including 290 GD, Sprinter 210/312/412 D, Vario with OM 602.94x as well as 350 GD, 350 SD/SDL, S 350 TD with OM 603.97x) need a different connecting rod.
- Note the weight class: On the OM601, OM602 and OM603, the connecting rods are weight-classified and fitted as a matched-weight set. Anyone replacing a single connecting rod must match its weight to the other connecting rods.
- Rule out turbo and other engine families: There is no approval of this number for the 190 D 2.5 Turbo, 250 D Turbo, 300 D Turbo and 300 SDL. The OM604, OM605 and OM606 are a different engine family.
- Condition and accessories: Our connecting rod is an unused new part in original Mercedes-Benz packaging; the packaging shows storage-related signs of aging. Connecting rod bolts are stretch bolts and must be replaced with every assembly – they are not part of the scope of delivery.
Solution
If a connecting rod is damaged, warped or no longer within tolerance at the big end, the only fix is replacement. We have exactly one connecting rod with the number A 601 030 46 20 in stock: new part from Mercedes stock (NOS), never installed, in original packaging. Price: 249,00 €. Once the single piece is sold, you can find further parts in our sections Mercedes W124 and Mercedes W201. If the crankshaft is also on the test bench during your overhaul, read our buying guide for the M103 crankshaft – there you will find the checkpoints for journals and grinding dimensions, which apply analogously to the diesel as well.
Connecting rod OM601 / OM602 / OM603 – new old stock (NOS)
A 601 030 46 20 · for variants with 84 mm stroke · genuine Mercedes-Benz, uninstalled
249,00 €
View offer →Compatible vehicles
| Model series | Models |
|---|---|
| W124 mid-size | 200 D, E 200 Diesel (124.120) |
| W201 190 series | 190 D 2.5 (201.126) |
| W202 C-Class | C 200 Diesel (202.120) |
| W463 G-Class | 300 GD, G 300 Diesel (463.220) |
Does not fit for Vito 108 D (W638), Sprinter 308 D / 408 D and T1 208/308/408 D (601 030 47 20 there), for the long-stroke versions OM 602.94x and OM 603.97x as well as for OM604, OM605 and OM606. There is no approval for the turbo versions. For other models, please compare the number on the old part.
FAQ
Does the connecting rod A 601 030 46 20 fit my W124 200 D?
Yes. According to product data, the number 601 030 46 20 is intended for the 200 D or E 200 Diesel of the W124 series (124.120). It also fits the 190 D 2.5 (W201, 201.126), the C 200 Diesel (W202, 202.120) and the 300 GD and G 300 Diesel (W463, 463.220). Please still compare the number on the removed connecting rod.
What is the difference between 601 030 46 20 and 601 030 47 20?
The 601 030 46 20 is intended for the engine variants with 84 mm stroke. The 601 030 47 20 is a different connecting rod for the long-stroke versions with 92,4 mm stroke, used in the Vito 108 D, Sprinter 308 D / 408 D and T1 208/308/408 D, among others. The two connecting rods are not interchangeable.
Does the connecting rod also fit turbo diesels such as the 190 D 2.5 Turbo or 300 D Turbo?
There is no approval of this number for the 190 D 2.5 Turbo, 250 D Turbo, 300 D Turbo and 300 SDL. Please check the number on the vehicle beforehand or send us the VIN.
Can I replace just a single connecting rod?
On the OM601, OM602 and OM603 prechamber diesels, the connecting rods are weight-classified and fitted as a matched-weight set. If only one connecting rod is replaced, its weight must match the other connecting rods of the engine. Clarify this with the engine rebuilder before installation.
Do I have to replace the connecting rod bolts?
Yes. The connecting rod bolts are stretch bolts and must be replaced with every assembly. They are not included in the scope of delivery.
KFZTeile-Thot is a specialist business for tested and refurbished Mercedes parts with its own test benches and has over 1.000 positive eBay reviews. Not sure whether the connecting rod fits your engine? Send us your VIN, we will check it free of charge: by phone at +49 179 8991069 (Mon–Fri 8 am–6 pm) or via our contact form.