Help Installing Thermostat Please.

[Serge]

Hello again fellas, I'm in the process of replacing my head gasket. Today I got the head off the block to discover that there was no thermostat? I have never seen this before... the gauge on the cluster always sat in the middle, anyway I went to put a new thermostat in and It wouldn't fit... I think I have the culprit but just need someone to back this up.

There is a yellow metal sort of ring attached to the block where the thermostat should be... is it wise to just pry it out? I took a photo below. Advice would be greatly appreciated. Serge.

[beemer1]

Weird, looks like half the thermostat is lodged in there!  I don't know what to say...

[romeomike]

Two thoughts:

Assuming there's a part number somewhere, you could look that up and prayerfully they'll include a set of pictures to help you determine what's normal.

Heat the assembly in a boiling pot of water. The aluminum should expand faster than the brass, then perhaps what's left of the "thermostat" can be removed more easily.

Let us know how it works out.

[1991 E30 M42]

There is a yellow metal sort of ring attached to the block where the thermostat should be... is it wise to just pry it out? I took a photo below. Advice would be greatly appreciated. Serge.

I think that piece of metal is whats left of the old thermostat and you should pry it out

[DesktopDave]

Looks like the support arch for the thermostat was cut off with an angle grinder.  :eek:  Absolutely go at it.  Put a thermostat in it's place.  If you have the replacement in your hands you'll see where the support bit holds the thermostat together.  Take a look at this RealOEM schematic:

If it's stuck I'd use a cut-off saw to make a relief cut or two in it so it'll bend or twist out.  Make sure you don't nick the head...

Good find; hopefully you'll have it all buttoned up soon!  Keep at it!