The bolts holding the water components on the front of the engine are the worst for snapping off. If it was over torqued in the past you are in for a nasty surprise...

Maybe someone on the forum has a spare 617 tstat housing, and they would be willing to help a new member out....or there is always PNP.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I was lucky its the top most bolt.
I have a air powered angle drill, tap , new bolt and never seize ready to go. along with a new thermostat and gasket.
If all goes as planned it shouldnt take more then 30 minutes

Gee Jay... How would you know this eh? (that 240 was a fun one wasn't it...)

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

The housing that the tstat sits in is fine. The bolt is snapped off on the engine block side in the threads