Coolant leak

MoMower · Dec 29, 2022

Ok diesel gurus, seeing a bit of steam and residue at the bottom of the thermostat housing, guessing the thermostat went bad, stuck shut and blew the gasket.

Not seeing any reason I should see steam coming from there? (That’s the question)

I’m competent with gas motors, not as much with diesel (but I believe the cooling system is close).

2019 GC1723, 725 Hrs

Thanks!

RjCorazza · Dec 29, 2022

MoMower said:
Ok diesel gurus, seeing a bit of steam and residue at the bottom of the thermostat housing, guessing the thermostat went bad, stuck shut and blew the gasket.

Not seeing any reason I should see steam coming from there? (That’s the question)

I’m competent with gas motors, not as much with diesel (but I believe the cooling system is close).

2019 GC1723, 725 Hrs

Thanks!

No reason there should be steam from the housing base. The gasket is likely bad as you surmise, but may or may not be related to a bad thermostat. Doesn't much matter, as you you'll want to replace the thermostat and gasket at the same time.
I do have a very vague recollection of having a steam leak at the thermostat housing on a vehicle years ago... There was a bleed screw on the housing that was leaking (?). Never seen a bleeder like that since.

ray66v · Dec 29, 2022

There is a bypass in the system if the thermostat sticks closed to relieve the pressure.

The thermostat gasket shouldn't be even close to being the weakest point in the system.

If the gasket is leaking, there is a bad seal there.

I would pull the housing, clean the surfaces and check for any defects. If none are found, replace the parts, reinstall, and see what happens.

MoMower · Dec 29, 2022

Thanks for the info!

About a week ago did have a small puddle (maybe a cup) of antifreeze on the ground and a low level in the reservoir. Never overheated, at least by the temp gauge.