Coolant temperature switch housing

[cfm65@me.com]

Hi Guys,
This gadget is leaking slightly on my 250SL engine. It is leaking at the bolt holding the unit against the block.
I would like to know how it seals against the block. Is there an O ring or paper gasket and I would imagine a copper type washer, sealing the bolt hole?
I really don’t want to open a can of worms here.
Regards
Chris
Ps I am not normally scared to open or repair a problem, however I smell a rat here.

[cfm65@me.com]

Hi Guys,
This gadget is leaking slightly on my 250SL engine. It is leaking at the bolt holding the unit against the block.
I would like to know how it seals against the block. Is there an O ring or paper gasket and I would imagine a copper type washer, sealing the bolt hole?
I really don’t want to open a can of worms here.
Regards
Chris
Ps I am not normally scared to open or repair a problem, however I smell a rat here.

[stickandrudderman]

No "gotchas" here. Just undo the mounting bolt and withdraw. You'll need a new seal which is item 84

[cfm65@me.com]

Thanks Colin,
Much appreciated.
Chris

[wwheeler]

Because the bolt threads are immersed in coolant, it may be stubborn getting started. You may want to drain the coolant first to avoid a huge mess. Hopefully the bolt seal ring will resolve the leak and the leak is not coming from the fitting that is on the head. That can be difficult to remove it has been on there for awhile.

[cfm65@me.com]

Tks Wallace,
Mine is definitely leaking through the bolt hole. Tks for the heads-up, re corroded bolt thread.
Much appreciated.
Chris