Basically my passenger floor mat was getting coolant on it. I searched the forums and found similar issues but nothing that matched my vehicle. I took it to a volvo mechanic for diagnosis and he said it was a bad o-ring on the heater core pipe (correct). Although he quoted me $900 to repair and said the dash would need to be removed (incorrect). The following will try to discuss my issue and my journey that took 8 hours, yet if I were to do it again it would only take 2 hours. Also my car has a previous owner and per AllData your car will only have this issue if the heater core has been replaced. I did not know that the heater core had been changed, but I guess it had.
First go to IPD or a dealership and buy new o-rings and clips. I suggest 2 o rings in case you loose one underneath the carpet…
Complete the following steps:
1. Remove battery cables (seriously… you’ll see why later)
2. Remove plastic skid plate underneath car
3. Access red petcock valve underneath radiator and drain out about a gallon or two of coolant (clean container to reuse)
Inside the car
2. Remove carpet retaining plastic screw thing on the right
3. Remove the black fabric that hides the computer/fuse box thing (you can see I am very technical)
4. Peel back floor carpet from the door to the radio
5. Lower fuse box by unlocking the plastic tabs
6. Take fuse box completely out of the white metal frame, this will take some negotiating
7. Unplug some of the harnesses that are nearest the center of the car to create better access to pipes (this is why you need to disconnect the battery. I didn’t and when I unplugged wires my car freaked out)
By now you should be able to see which o-ring is leaking. Mine was the lower pipe and the retaining clip had popped off as well (if yours is still on take it off by prying upwards with a flathead screwdriver where the retainer clips together).
The objective will be to separate the pipes. This is way easier then you may think. Instructions are to follow:
1. Use a smaller torx (I forget the size) and loosen the screw that is holding the pipe in place at the firewall
2. From the engine compartment pull on the hose that is connected to the pipe you are trying to separate. Note: I did not have to disconnect any of these connections, rather keeping the connections fixed helped me slide the pipe out through the firewall a little.
The hoses to the right are for the heater core
3. Inside the car you should see the pipes separated enough to access the o-ring.
4. When installing the new o-ring you must accurately seat it in the female section of the pipe. DO NOT slide over the male end… it will not compress together.
5. From the interior pull the pipe on the firewall side into the other pipe. This should get completely closed and you will not see the o-ring.
6. Reattach NEW clip (new just to ensure tight fit)
7. Reverse remaining instructions.
Good luck and PM me with any questions. I should be alerted via email and will try to help out. Really helps to have 2 people. I had my dad and I am not sure what I would have done without him. *Sorry for the lack of pictures. I must have deleted them and can’t find them anywhere.
Peace!