The Swedish Fish - 2000 Volvo V70XC

3 minute(s) of a 12 minute read

Now onto the heat issue! I bought an infrared thermometer to try and diagnose what was going on. By taking temp readings at the major coolant junctions I figured I could diagnose the failed area of my heat. Mind you, the car was coming to temp properly, so the thermostat wasn't the issue, it was only something with the heat. The readings all came out normal, but for some reason the heat coming out of the vents was just luke warm. I figured maybe the heater core is clogged, I'll do a clean and flush of the whole system. That ended up being a good thing to do because the system was pretty cruddy looking, and it wasn't using the blue Volvo coolant, so at least I now knew the coolant was new, and what brand was in it. 

After all that and still getting luke warm heat, I decided to just swap the heater core. I bought a new one from Advance Auto Parts since it came with a lifetime warranty, and swapped them. That fixed the problem. The core wasn't clogged, but it had been replaced since it wasn't an original Volvo unit. The old unit had no brand or part number on it, and as you can see in the comparison photos, is definitely a cheap unit. I wish I knew what it was so I could tell people to avoid it, but it shall remain a mystery I guess. The old one is on the left, new one on the right!

One last issue I had was with the Climate Control Module. For whatever reason if the fan was on, the AC was on. I pulled the AC relay to keep the compressor from turning on, but it always wanted to turn the AC on. Didn't matter what temp I had set, which area I had selected to blow the heat, that AC button was on. If you read the owners manual the AC will automatically come on if you have defrost selected, but should shut off under any other selection, that wasn't the case for me. I ended up taking a chance and buying a used unit to swap out and see if it fixed it. The new to me unit worked exactly how it should. The part numbers on the outside were the same, but the sticker on the internal board was completely different. I'm not sure what got crossed with the unit that came in my car, but glad it was as simple as swapping out the unit and not some larger issue.