Thermostat hole position & Gasket Orientation (1 Viewer)

[SAB]

1980 BJ41
2B

1. Does the black raised "ring" on the gasket go face down or face up in the lower thermostat housing?

2. Should the hole in the thermostat be positioned at dead center between the rear 2 mounting holes or at 1 or 2 O'clock? I see that for the 80 guys it should be at 12...but not sure if that carries over for the B engines.

The FSM doesn't seem to clarify (unless I'm missing it.)

Thanks in advance!

 

[roscoFJ73]

I dont think the hole would matter much if there is nothing on the housing to line up with.
I might be wrong but I was under the impression they were just there to stop pressure getting to high if the thermostat fails to open
Look like the rubber goes against the thermostat downwards. But I cant see that making much difference either. Is it an OEM gasket? I cant find a pic of other gaskets with a rubber o ring .

 

[SAB]

Thanks for the reply Rosco...You're always quick to help out around here. It is appreciated!

The thermostat and gasket are OEM. I ended up cleaning up the surfaces, applied some sil-glide to the gasket and positioned it o-ring side down, anti-seize on some new OEM thermostat housing bolts (which now come coated or plated in some sort of grey finish).

All went well. No leaks as of yet.

The temp. gauge still only climbs to about half way between the L and mid mark. Still no interior heat, but the bottom of the heater box is hot at the bottom. All of the lines are hot. I suspect the heater valve may need to be replaced next, although it was actuating fine when I inspected it during the flush.

For the record, I flushed the heater core, radiator, and block until it was all running clear. Then I burped the system using a funnel insert that replaced the radiator cap. New cap too.

 

[roscoFJ73]

Are the hoses in and out of the heater core warm/hot? Not sure about the 40 series but the 70 series like having the heater core flushed backwards.

 

[SAB]

They are hot. Blower is working fine too (although nothing happens when I switch the lever to activate the defrost).

 

[roscoFJ73]

Are all the controls working ok, flaps opening etc?

 

[SAB]

That I have yet to confirm. The rear heater works great. The manual lever that switches from cabin to defrost will close a flap that shuts off the cabin air...but where it goes from there is a mystery at the moment. I'll probably have to get into the heater box and see what's going on in there.

Does your temp gauge sit dead center when up to operating temperature?

 

[roscoFJ73]

Yeah but its a 75 series. It doesnt move much between winter and summer. It gets to about halfway in 10 mins in winter and about 6-7 minutes in summer. Heater starts to blow warm after 500-600 metres in winter, same time gauge moves off the bottom.

 

[Dave 2000]

Hole is simply to aid trapped air behind the stat to pass through whilsts it's closed air rises so hole at the top. If the thermostat fails to open the entire system as it heats up would be under pressure, both in front and behind the stat.

Regards

Dave