So my 240 has started to leak coolant inside the car. I get full heat as needed and can modulate the temperature pretty decently with the control slider. Coolant pools only the driver's side. It happens when the slider is on the heat side. No coolant leak/drips whatsoever on the cool side. I dont smell any coolant smell when the heater is on and neither is there any funky vapors on the windshield.

See following pictures:

Based on these - do you think its the heater core or the heater control valve? And where can I find good quality parts for repairs?

 

that looks like the heater control valve to me.

I used these guys kit to replace the valve on our 240 (which was old style, but it works for new style, too). uses a 1970s dodge truck heater valve, which is all metal, and works great. Volvo 240 heater valve : EuroPartsHouse
Volvo 240 heater valve kit replaces 1348252 9131998 $59! Volvo 240 heater valve kit replaces 1348252 9131998 $59 [] - $59.00 : EuroPartsHouse

 

Ok. I will order that kit. There are ones online for 1977-80 dodge (d150) truck for $20.00. Looks exactly the same - does anyone know if those will work? It's four seasons 74677.

I ask because based on the Europartshouse website - since my car has the new style plastic valve - I only need the replacement valve and everything else remains the same. Also, the Dodge style part has a 90 degree elbow on it. The plastic valve in my car is currently "in -line" between the 2 hoses. So can I not just use the metal valve and connect it straight without the 90 degree elbow?

Is there anything special in replacing the heater control valve? Or just pinch the hose on the driver's side, put rags on the floor, disconnect the hose clamps, remove the adjust cable and swap out?