Help needed Coolant Leak

[paul_GB]

Ah.. help needed. Ive just installed my rebuild 230 engine.. she turns over fine on the starter (plugs out).. and no oil leaks. Before enevn attempting to fire it up I part filled the coolant (with additive).. and ive got a leak coming out of the area behind the water pump (apears to be seeping out the gasked that interfaces to the front of the block).. this is the 'two bolt' gasket. ALSO (alarmingly) coolant seeping out of the crankshaft front oil seal (the outside edge). Im baffled at the moment.. Ive just drained it and walked away for the evening.. will take a closer look later when Ive calmed down. Any ideas what have I done wrong..?  :'(

[66andBlue]

Perhaps the bolts below the chain tensioner are not tight enough?
See photos showing location here: http://www.sl113.org/forums/index.php?topic=2360.msg15051

[JimVillers]

Paul .... The water pump has three bolts holding it.  Two with the gasket that seals the water opening and a third in the upper right.  You probably forgot to put the spacing washer between this part of the water pump and the block (item #30).  Without the washer, the gasket will not seal.  You can insert a washer by loosening the bolts and then sliding it under the edge.

With the washer, the leak will stop and so will the water around the crank shaft.  

[tel76]

Jim,
What material is washer 30 made out off?
On a 1982  280sl it is a fibrous material but when i bought one for my 1968 280sl it is a steel washer.
I have not yet fitted the waterpump until clarify this point.
If i fit the steel washer it could have the same detrimental effect as not fitting a washer. ie-the 2 bolts will not pull down evenly.

[paul_GB]

Alfred.. I did actually check those bolts and they are tightened fine.
Jim.. I think you might be spot on - I dont remember refitting that washer.!! Great advice - thanks. Strange thing is that I NOW remember reading about that washer in other forum threads. But I also dont have one left over from the rebuild (!). Any clues as to the thinckness of the washer..? I am thinking its probably critical. I will verify this is the problem tomorrow.. but I feel convinced it is. Will report back.

[paul_GB]

.. Yes the washer is missing..! I will report back on whether a washer fixes the prob (I am very optimistic).
I guess the washer on this bolt compensates for the thickness of the gasket on the other two bolts.
Are you aware of the type/size it should be.. maybe it is fiber.. (as per Jims query). Should I get the correct item from MBZ if its available..?

[bpossel]

Hi Paul,

Maybe put a thin layer of Permatex on the washer also....
Bob

[tel76]

Hello Paul.
The washer is available from MB but it is a steel washer and as i indicated above it should be flexible as per the two hole gasket.
I have made a washer out of gasket paper the same thickness as the two hole gasket.

[JimVillers]

Paul ... I just used a thin steel washer on mine.  You can judge the needed thickness by tightening the lower two bolts and then use a feeler gauge to measure the gap.  I think that it just needs to be "ball park" close.

[paul_GB]

.. latest state of play... Ive replaced the gasket on the pump housing and tightened down the two bolts to see if it holds water ok. BUT there was still a leak..!! Ive just doubled up and used two gaskets (together) and it seals ok now. I think the housing/block face on the alloy casting is damaged (it has seen better days).. Im not convinced the face is totally flat.

Im not overly happy with leaving the double gasket arrangement in situ so I will try and source a replacement pump housing casting.. I think Roger Edwards Motors can help. Thanks for the help guys..  excellent as always.

[paul_GB]

.. and finally, to conclude.. A replacement water pump housing solved the leak.. note, I bought the washer from MBZ (for the third bolt).. for ref it is steel and 0.9mm thick. Thanks for the help