There is corrosion around the trans cooler connections to the radiator and the radiator itself is showing signs of seepage from the top. Two questions: 1) is replacing the radiator as simple as removing and dropping in the new one or does the AC condenser need to be moved? and 2) is there supposed to be a plugged connection on the passenger side of the radiator? There is a small piece of hose with two clamps on it a few inches below the top of the radiator. - Thanks in advance.

 

Fairly simple to remove the radiator. Fan has to come off, but not the condenser. You should also replace the large coolant hoses and the $ 6 thermostat. In fact all hoses in and around front and rear of engine. All are cheap.

Yes. Radiators have a unused port on upper Passenger side. It is there for a coolant sensor that used to control the Engine Cooling Fan, used in older Volvos. S90's fan is controlled by ECU, so you don't need that sensor.

You need to plug that hole. IIRC there are two holes -- one male and one female. Both need to be plugged. Male port can be plugged with a Hole Plug from the Auto Parts Store Deft Motion | Hybrid Racing Heater Hose Delete Cap - Hybrid Racing - Brands

Female open port can be closed with this T-Handle Expandable Rubber Plugs 1/2" to 4" - Petersen Products Company

 

Well, it is complete. The radiator was fairly simple and I have no extra parts. I picked up a heater control valve at Pick n Pull and replaced the old one which was leaking. My only issue is that I could not get leverage to replaced the heater hoses. They are not swollen, but my feeling is that they ought to be replaced. Since I bought the car with 105K on it and there was no indication that the 100K transmission service was performed that was completed this afternoon. I did pick up a nice whistle which was traced to the vacuum hose on the HCV. I think this leak was the reason for the 505 code that appeared today.

 

Be very careful when putting the transmission coolant lines back in. The pipes must be perfectly aligned and the seals must be perfectly flush. Any misalignment can let coolant into the transmission which will destroy the unit. My friend destroyed his S90 because he made that mistake.