84 BJ42 Thermostat Gasket direction

[GS 60]

Hi
Need advice of which way round for Thermo gaskets.

Lower Housing:
Does the raised side go to block or lower housing?

Water Outlet:
Does the side with O ring embedded go to lower housing IE O ring over Thermostat?


Thank you.

 

[jim land]

bump , i also need to know the correct orientation of those gaskets

 

[jim land]

What is your advice @gerg

 

[gerg]

So as far as I know gaskets with raised portions like that are for flanges that also have raised sections designed to increase pressure in that specific area. Then I think each raised area faces one another. As far as I've ever seen 3B housing surfaces are flat. In that case I dont think it matters which way it goes as both surfaces are essentially the same.

So o rings usually have a reciever they sit in or a metal ring they fit over that is just slightly shallower than the oring thickness. This keeps the oring from distorting and causes it to compress evenly with more force where the oring is compared to the rest of the flange.

I would think it's a similar concept to the raised gasket I spoke about above but fills defects more easily and confirms to surfaces that might not be perfectly flat easier cus the ring is fairly think and pliable. Probably would also allow signifigant movement between the two surfaces cus one is aluminum and the other is cast steel which expand at different rates. If both were fixed strongly with a gasket that couldn't accomidate the movement it would rip apart and fail over time.

So that being said I've never used a top thermostat gasket with an oring before so I'm not exactly sure. I'd try both ways to see if one causes the housing to sit lower into its recess like in a more natural way. I'd be worried the housing might sit up really high and the both flanges might not contact or it would gap excessively. If it got weird both ways I'd probably remove the o ring and use it like a regular gasket. So I'm not a gasket expert. I'm not an expert in anything actually and often use silicone instead of gaskets with great success. I wouldn't do it if it didn't work. Some folks think that just plain crazy. I take that as a compliment.

Confusing enough?
Cheers

 

[GS 60]

So as far as I know gaskets with raised portions like that are for flanges that also have raised sections designed to increase pressure in that specific area. Then I think each raised area faces one another. As far as I've ever seen 3B housing surfaces are flat. In that case I dont think it matters which way it goes as both surfaces are essentially the same.

So o rings usually have a reciever they sit in or a metal ring they fit over that is just slightly shallower than the oring thickness. This keeps the oring from distorting and causes it to compress evenly with more force where the oring is compared to the rest of the flange.

I would think it's a similar concept to the raised gasket I spoke about above but fills defects more easily and confirms to surfaces that might not be perfectly flat easier cus the ring is fairly think and pliable. Probably would also allow signifigant movement between the two surfaces cus one is aluminum and the other is cast steel which expand at different rates. If both were fixed strongly with a gasket that couldn't accomidate the movement it would rip apart and fail over time.

So that being said I've never used a top thermostat gasket with an oring before so I'm not exactly sure. I'd try both ways to see if one causes the housing to sit lower into its recess like in a more natural way. I'd be worried the housing might sit up really high and the both flanges might not contact or it would gap excessively. If it got weird both ways I'd probably remove the o ring and use it like a regular gasket. So I'm not a gasket expert. I'm not an expert in anything actually and often use silicone instead of gaskets with great success. I wouldn't do it if it didn't work. Some folks think that just plain crazy. I take that as a compliment.

Confusing enough?
Cheers

As Gerg pointed out, the 3B housing surfaces are flat In the end, I pointed the raised side out towards the bottom Thermo unit, flat side to the block. For the top cover, I pointed the raised side up, flat side matted to the bottom of Thermo unit. Also added a thin skim of silicon. So far, no leaks. As Gerg said, on the 3B , don't think it matters. I guess adding a thin sliicon skim would hedge your bets. Only fitted Thermo last week, will let you know if there are any issues?
Thanks

 

[GS 60]

As Gerg pointed out, the 3B housing surfaces are flat In the end, I pointed the raised side out towards the bottom Thermo unit, flat side to the block. For the top cover, I pointed the raised side up, flat side matted to the bottom of Thermo unit. Also added a thin skim of silicon. So far, no leaks. As Gerg said, on the 3B , don't think it matters. I guess adding a thin sliicon skim would hedge your bets. Only fitted Thermo last week, will let you know if there are any issues?
Thanks

One other pointer is the Water Pump gasket. My water pump gasket was similar to Thermo gaskets IE one raised side. This gasket only fits one way, so from memory, the raised side was towards the pump with the flat side towards the block?

 

[gerg]

Are these things known to leak a lot? Usually I never use a gasket, put a swipe of silicone on them, tighten them down as tight as tight should be, not really paying much attention to it and never have had a problem. Is that weird?

 

[GS 60]

I have seen plenty of posts on leaking around the water pump and Thermo housings. I didn't have a leak, I was just refurbing my entire cooling system. However, when I took the pump and Thermo unit off, the old paper gaskets were in bits and was surprised that they were holding the coolant in? It's easy to replace the Thermo gaskets, a real pain to take the water pump out, so, I would not have changed either unless I had a leak. I guess its like any car part that has a gasket seal, if you are taking it out for any reason, change the gasket (or use silicon), if not, leave good enough alone?

 

[gerg]

Yeah ok, I can see that. I guess once you have a problem in one area your alot more conscious about it next time you work on it.

 

[jim land]

Im actualy in the water pump and t-stat install so I will share a couple of pics for future reference

Some may say its not the correct way to do it , but this how I did it. , im not an expert

Old dry gasket to clean

 

[jim land]

After the surface is clean I put a thin coat of rtv to fill the scratch plus it help to keep the gasket in place

 

[jim land]

Water pump bolts torque at 18 ft-lb , I use copper antiseize on the bolts

I also use rtv for the t-stat housing

 

[jim land]

Housing

 

[jim land]

More

 

[bcsteel]

Jim,

As usual nicely done and and thanks for detail.

 

[GS 60]

Looks great, did you add another sensor, have much trouble getting the cap of spare Thermo port? Where does the feed go back to?

 

[jim land]

To remove the square plug you need to heat it with a small torch and pour cold water on it , after it came out easy

I chose to add a mechanical temp gauge. , only thing is the tip need more clearence to fully seat, this part of the housing is very thick so I drill a little bit