Experts, I've bought an after market water pump for M272 engine, and the two top holes where the serpentine belt pulleys are to be installed are not threaded.

How are those pulleys installed? Are there some backing nuts and no thread in the holes, or am I supposed to thread the holes? Thanks!

 

MB lately is using self-tapping bolts for fast assemble.
I guess this is what you have. Do original bolts have cutting notch?

 

Sounds like a possibility. Unfortunately I don't have the original bolts (it's a project build with new parts). Maybe I'll buy those bolts directly from Mercedes to ensure the right size/type/self threading, unless there are different suggestions.

Dzięki!

 

Bad news, the size of the holes in the pulleys is 8.2 mm and the size of the unthreaded holes in the water pump is 8.4mm, which is a size for threading M10x1.5

M10 bolt will not go through the pulley hole of 8.2mm

Is anyone having both the pump and the pulleys (and the bolts) and can comment on the sizes? One of the pulleys came with M7 bolt. Thanks!

 

That sounds like time to send aftermarket pump back and order OE one.

 

Pump or the pulleys, that's why it would be great if someone with those parts on hand/doing the job could confirm the hole dimensions of both the pulleys and the mounting holes, thanks

 

More information, looks like Mercedes OEM is using BOTH threaded and not threaded water pumps depending on the engine number. Same with after market water pumps, can be both threaded and not threaded. Which means that the pulleys most likely also have two hole dimensions, unless the threaded water pumps are already threaded for M10x1.5

 

ANY reputable seller will match the part to your VIN.
It is your choice to make it hard to solve issue.

 

If it was that simple we would not have this discussion.

The engine came from a car with a completely different VIN, completely different water pump matching that VIN (and matching that engine number), and completely different accessories than the car I'm building.

 

For such situation, MB stamps or labels part number on each part. Even small brackets.

 

if you have the vin of the donor car, I can look up the PNs for the various parts and fasteners.

 

Those pulley use a M6 or M8... definitely not M10 on W212 M272. OEM INA pulleys, the smaller composite one comes with a bolt and the larger metal one did not. As mentioned, your best bet is using the VIN off the car the engine came from or find the P/N stamped on the original parts... which I guess we may suspect is a W211.

*edit*

this one has threaded boses: https://www.fcpeuro.com/products/mer...ump-2722000901

OP, what pump did you order? Maybe its a dud.

 

The WP is the same from W211-W212, Feb 2005 - on