Volvo Penta MD7B - thermostat

[Mrstarskydean]

So it has started leaking, a very very little, and has started to corrode. Engine seems to be fine, does not overheat (how does one tell?) but... time to replace the thermostat? What do I need to complete this? A kit? Looking on the web it appears that silicone 'grease' is used to seal with any gaskets - brands recommended?

 

[pvb]

I believe that the MD7B thermostat housing is sealed with 2 O-rings, which are available VP parts. You could clean up the housing, and paint it. If the engine isn't overheating, the thermostat should be OK, but you can easily test it.

 

[VicS]

So it has started leaking, a very very little, and has started to corrode. Engine seems to be fine, does not overheat (how does one tell?) but... time to replace the thermostat? What do I need to complete this? A kit? Looking on the web it appears that silicone 'grease' is used to seal with any gaskets - brands recommended?

It looks to me as though the leak may just be between the hose and the elbow on the top of the thermostat housing. Id clean it up and remake that joint / replace the hose . I doubt if the second hose clip ( normally there is only one ) is doing any good.

This page shows all the bits and pieces. https://www.volvopentashop.com/vols...DieselEngines/7742080/7742080_26/7742080_017D
Most are available from Volspec
Some will be avaialble at lower prices from Keypart https://keypart.com/volvo-penta/diesel-engine/md7b/19811983

The thermostat should just start to open at 60C if you decide to test it. That temperature should be marked on it. The temperature at which it is fully open may also be marked on it

Take great care undoing the bolts that hold the thermostat housing on. You really really do not want to break either of them. They look as though they might never have been undone before

 

[Mrstarskydean]

many thanks for these kind replies; I'll proceed with some some circumspection - and as many parts as I can get in advance...