Replacing Water Pump
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Junior Member
Joined: May 2024
Posts: 31
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W203 C240
Replacing Water Pump
Will be replacing my water pump on the C240 ( W203 with M112 engine )
Car is only at 33K miles but the current water pump is clunking a bit and has some play in it.
Merc wanted £400 for the part so I went aftermarket and got an INA ( German part, designed specifically for Mercedes ) one, instead.
My car has an oil cooler so the pump itself has 3 connectors on it.
I will make a stencil around the gasket on some cardboard and then place the bolts into it as I go, so I know where they go when re-installing.
I understand a couple of the holes in the new part will not have threads and therefore will have to put the " self tapping " bolts which are on the car in them to create threads. Is this correct ?
Any advice at all please ? I know it is a fairly big job but should manage it.
Car is only at 33K miles but the current water pump is clunking a bit and has some play in it.
Merc wanted £400 for the part so I went aftermarket and got an INA ( German part, designed specifically for Mercedes ) one, instead.
My car has an oil cooler so the pump itself has 3 connectors on it.
I will make a stencil around the gasket on some cardboard and then place the bolts into it as I go, so I know where they go when re-installing.
I understand a couple of the holes in the new part will not have threads and therefore will have to put the " self tapping " bolts which are on the car in them to create threads. Is this correct ?
Any advice at all please ? I know it is a fairly big job but should manage it.
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,275
Likes: 172
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
I did the water pump on m'lady's old ML with 112 3.2L .
What a PIA! M111 was a breeze! I bought the pump from a mechanic, so I was lucky, I had some
support in doing the job.
Just like you he said, get a piece of cardboard, draw an outline of the gasket and put the bolts in
the cardboard in corresponding holes. That process saved my butt!
Not sure about the self tapping holes. That was like 15 years ago.
That vehicle had belt driven fan belt and required special wrenches to get it off,
which thankfully the mechanic loaned me. I think I paid $275 for that MB water pump ha!
A lot for a water pump! But I would have been lost without the help of the mechanic.
The only other thing I'll add, same mechanic had a customer bring their own water pump
for M272 engine, and ended up completely hosing the engine due to thickness of metal
around the pump holes being different and causing a bolt to get caught in the timing chain and
cracking the timing cover. Now, did he put a bolt out of place? Or was the aftermarket part's
thickness dimension thinner on the one hole??
We'll never know. But to you I say, mic out the thickness of the metal
where the holes are and compare them to the original before install.
Just to be sure.
What a PIA! M111 was a breeze! I bought the pump from a mechanic, so I was lucky, I had some
support in doing the job.
Just like you he said, get a piece of cardboard, draw an outline of the gasket and put the bolts in
the cardboard in corresponding holes. That process saved my butt!
Not sure about the self tapping holes. That was like 15 years ago.
That vehicle had belt driven fan belt and required special wrenches to get it off,
which thankfully the mechanic loaned me. I think I paid $275 for that MB water pump ha!
A lot for a water pump! But I would have been lost without the help of the mechanic.
The only other thing I'll add, same mechanic had a customer bring their own water pump
for M272 engine, and ended up completely hosing the engine due to thickness of metal
around the pump holes being different and causing a bolt to get caught in the timing chain and
cracking the timing cover. Now, did he put a bolt out of place? Or was the aftermarket part's
thickness dimension thinner on the one hole??
We'll never know. But to you I say, mic out the thickness of the metal
where the holes are and compare them to the original before install.
Just to be sure.
Last edited by C230 Sport Coup; Aug 4, 2024 at 02:37 AM.
