Coolant connection : no seal ? no gasket ?
 

The aluminum water pipe on top of the engine block connects to a black steel pipe on the passenger side, rear; I believe this is the heater return line. The end of the steel pipe slips snugly into a machined hole in the aluminum water pipe, and a small screw on a tab holds it in place.

Q) Is there any gasket or seal for this connection ?

There isn't anything shown in the parts diagram at subaruparts.com (the pipes are joined in the picture). It seems like there has to be something ! Should I use some gasket maker ?

TIA,

Jeff

I don't know of any seal or gasket. Maybe someone else has an idea about this.

If no one else answers in the meantime, I can take a look tomorrow night when I get home...

Maybe it's just a smooth, tight fit. But I checked thermal expansion coefficients, and aluminum expands more than steel, so it's gonna tend to get a little looser at higher temps. :confused:

Well, I found that I had a water pipe from an EJ25 that is resting in peace (pieces) in my shop. It too has a connection just like the one I asked about. So I undid the nut and took it apart. Man this one was stuck in there good ! But no gasket, no sealant - just a good tight fit. I guess the water pressure is pretty low on top of the block on the return side of the radiator, but I never imagined a joint like that would work.

Anyways, just to be safe, I smeared some gasket sealer goo around the flange.