I have a 1998 S90. (I've also posted this in the 960 forum.) When I turn on the heat, it works, but I smell coolant. And I have a wet spot near the transmission hump at the firewall end of the passenger footwell. My coolant level warning light also just came on. Is this a leaking heater core, or are there other hoses under there which could account for this without the major ordeal of heater core replacement? It's always something.

 

its either the heater core or the o-rings between the hoses that go through the firewall into the heater core. There's some vids on YouTube on how to do this on the 850s, not sure if its exactly the same as the S90, but should give you an idea of what to do. Generally you need to remove the two sides of the center console, drain the radiator then unscrew the heater core retaining screws and slide the core out from the drivers side to the passenger side of the console. With that said, if its only the o-rings, you can pop the hoses off, replace the o-rings leaving the heater core in place and hope for the best. :-)

 

Are the O-rings on the engine compartment side of the firewall? I've seen instructions for a 960. Looks like most of the disassembly was under the driver's side, but the photos weren't very clear. Assuming hose connections are on the engine side of the firewall (like most cars) and the pipes on the core itself go through grommets in the firewall. Is that correct??

I'm groaning about diving into this. Core isn't expensive, but the labor looks like a P.I.T.A.

 

hoses punch through the firewall. the o-rings sit between the heater core and the hose ends. Usually the replacement heater core comes with the o-rings.

 

Is there a way you can check for leaks without pulling the sides of the center console off?