OM616/OM617 prechamber A6160100152 – buying guide W123 W460
Anyone overhauling the cylinder head of a W123 240 D, a G-Class 300 GD or a T1 207 D van will sooner or later come across the prechambers. They sit deep in the head, get very hot with every combustion and after decades are often cracked or attacked. New prechambers for the old Mercedes diesels are now hard to get. This guide shows how to recognize a worn prechamber, what to look for when buying, and which vehicles the A 616 010 01 52 fits.
How do you recognize wear or damage?
The injector sprays into the prechamber, where combustion begins. The burning mixture then flows into the main combustion chamber – this gives the Mercedes prechamber diesels their smooth, quiet running. One prechamber is fitted per cylinder, directly below the injector; the glow plug protrudes into it. It is held by a threaded ring. Whether a prechamber needs replacing usually only becomes apparent with the injector removed or the head off.
| Finding | Meaning |
|---|---|
| Broken off or missing ball on the prechamber | Prechamber defective – typical consequences: knocking on this cylinder, shattered glow plug, heavy smoke on cold start. Replace. |
| Shattered or broken-off glow plug | Often a result of the damaged prechamber – check the prechamber before installing a new glow plug. |
| Bubbles at the prechamber ring | Prechamber leaking – usually together with less compression on this cylinder. |
| Compression clearly lower on one cylinder | Can be due to the prechamber, but equally to valves or piston rings – check compression and valves as well. |
| Blue smoke and increased oil consumption | Usually not prechamber damage but hardened valve stem seals – see Valve stem seal guide (using the OM601 as an example) |
| Engine shakes when switched off | Not a prechamber issue – more likely the engine damper, see W123 300 D engine damper guide |
Causes
The prechamber is the most thermally stressed part in the cylinder head of a prechamber diesel. Every cold start and every full-load drive means large temperature swings. Over hundreds of thousands of kilometers, cracks form and the front part can break out. A dripping or incorrectly spraying injector adds to the stress. If a piece breaks out, it often hits the glow plug – so a shattered glow plug is a clear indication of the prechamber.
What to look for when buying
- Identify the engine: The A 616 010 01 52 is intended for the OM616 four-cylinder and the OM617 five-cylinder without turbo. The OM615 (200 D, 220 D) has its own prechamber with the number A 615 010 01 52.
- Compare the model year: According to the literature, the prechamber was changed in August 1978. On a W123 built before 08/1978, please compare the number of your old prechamber.
- Rule out turbo: This prechamber does not fit the OM617 turbo (300 SD, 300 D / 300 TD / 300 CD Turbodiesel), nor the OM601, OM602 and OM603.
- Plan quantity and sealing rings: The OM616 needs 4, the OM617 5 prechambers. The sealing rings at the bottom of the prechamber can only be used once and are not included (MB 615 017 00 60 standard size, repair sizes 615 017 01/02/03 60). The thickness depends on the protrusion. As tools you need a pin wrench for the threaded ring and a puller.
- Check the condition: With “new” prechambers, look for undamaged bores and flanges without rust. Our four prechambers are uninstalled, rust-free and show only small machining marks next to the cross bore.
Solution
If a prechamber is cracked or broken out, the only fix is replacement. It makes sense to renew all prechambers together while the head is open. We have exactly one set of 4 prechambers for the number A 616 010 01 52: new old stock (NOS) from the manufacturer ed, never installed, in the original packaging (Styrofoam block with label “DB 240 / 300 DIESEL”, “ed-No.: 0512 N”, “Original-No.: DB 616 010 0152 N”). The label is torn off at the top left, and the Styrofoam is frayed at one corner. It is a spare part from ed, not a part with the Mercedes star. Price for the set: 299,00 €. Once the set is sold, you can find further parts in our section Mercedes W123. If the valve train is also due during your engine overhaul, read our OM616/OM615 camshaft buying guide.
4x prechamber OM616 / OM617 – new old stock (NOS)
for the number A 616 010 01 52 · ed 0512 N · Made in West Germany · set of 4 pcs
299,00 €
View offer →Compatible vehicles
| Model series | Models |
|---|---|
| W123 (02/1976–11/1985) | 240 D (OM616), 300 D (OM617) |
| S123 T-model | 240 TD (09/1977–02/1979), 300 TD (09/1977–11/1985) |
| W460 G-Class | 240 GD (03/1979–08/1987), 300 GD (12/1979–12/1991) |
| Transporter T1 (601/602) | 207 D, 307 D, 309 D, 409 D |
| T2 | 507 D (1977–1990) |
Does not fit for OM617 turbo (300 SD, 300 D / 300 TD / 300 CD Turbodiesel), OM615 (200 D, 220 D), OM601, OM602, OM603 and the W115 240 D and 240 D 3.0 (not approved). On a W123 built before 08/1978, please compare the old number.
FAQ
Does the price cover all four prechambers?
Yes. The price of 299,00 € applies to the set of 4 prechambers. For the OM616 four-cylinder this is a complete set; the OM617 five-cylinder needs five prechambers, so one is missing with this set.
Does the prechamber A 616 010 01 52 fit the 300 D Turbodiesel?
No. The turbo versions of the OM617 (300 SD as well as 300 D, 300 TD and 300 CD Turbodiesel) are expressly excluded. The prechamber is intended only for the OM616 and OM617 without turbo.
Does the prechamber fit the W123 200 D or 220 D?
No. The 200 D and 220 D have the OM615, which has its own prechamber with the number A 615 010 01 52. This set is also not suitable for the OM601, OM602 and OM603.
Are the sealing rings included in the scope of delivery?
No. At the bottom of each prechamber sits a sealing ring that may only be used once (MB 615 017 00 60 standard size, repair sizes 615 017 01/02/03 60). Which thickness you need depends on the measured protrusion of the prechamber.
Is this a genuine Mercedes part?
It is a new part from the manufacturer ed, stamped “MADE IN WEST-GERMANY”, made to the original number A 616 010 01 52. It is not a part with the Mercedes star. The four prechambers were never installed and come in the manufacturer's Styrofoam block.
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 prechamber 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.