Removing The Heater Box

After spending much of last weekend eyeballing the heater unit and formulating a gameplan, it was go time! I figured since the heater doesn't work anyway, I coudn't wreck it any further! Besides, if I was in "way over my head", I could always revert to plan A which is to send it to the shop. Before commiting to the destruction derby, I invested some time in taking lots of photos and labeling everything so that I'd know how to put everything back together. In my experience with the Volvo thus far, there's always that one screw or one nut that's not with the program - that just refuses to budge or have the threads all worn down. Well ... it was no different in this case, but I was prepared for it this time as I quickly singled it out while eyeballing the battle field last weekend. As this could be the deal breaker, I made the removal of this one problem nut the first step. This sucker is out of 4 nuts that secures the heater box to the firewall in the engine compartment - and it's just a pain to get to! Tucked right between the firewall and the heater box, and under the air intake duct, there's just not enough room to work a wrench from either direction. After about 20 minutes, I finally did get a couple of good turns of the wrench to loosen up the nut. It was another 10 minutes of turning the nut with my fingers before I got it out! Good thing I spent those 2 weeks in the Shaolin Temple as a young boy strengthening my fingers studying the sacred art of "Slouching Tiger Squatting Dog." Note to self: replace this nut with wing nut in case I have to do this again in the future.

Defroster Hoses Under Dash:

After Removal of Defroster Hoses:

My heater removal check-list pretty much went as follows:

1. Label and photograph everything - check
2. Disconnect electric cables from blower motor - check
3. Remove heater defroster hoses from under the dash - check
4. Disconnect floor and defrost control cables from heater box (car interior) - check
5. Disconnect temperature control cable from heater control valve (under dash) - check
6. Remove radiator cap and coolant overflow bottle cap in preperation for draining the heater core - check
7. Line the garage floor with spill trays to catch runaway coolant while draining the heater core - check
8. Have plastic bottle ready to hold drained coolant from heater core - check
9. Pull hoses from heater core and drain coolant all over engine compartment and garage floor while carefully avoiding the plastic bottle - check

I ended up "borrowing" the aquarium gravel siphon from my fish pond to catch the remaining 3 or 4 drops of coolant from the heater core and to funnel the flow to the spill trays on the ground.

Heater Control Valve:

Draining Coolant From Heater Core:

While I was under the dash labeling components, I noticed that the heater control valve had this long copper-like wire that was just dangling freely and leading to nowhere. I later found the "other" half of the wire coiled in an "S" shape inside the heater box right next to the heater core. Turns out that this is the capillary sensor cable from the temperature sensor in the heater control valve to the heater core in the heater box - yes mine was already broken. If it wasn't, the heater control valve would have to be removed from under the dash and the entire contraption - heater box, attached capillary sensor wire, and heater control valve would be removed as a single unit when pulled from the engine compartment. It doesn't seem that bad as I think the heater control valve has enough of the capillary sensor wire left to just run what's remaining back into the heater box. If this thing is supposed to regulate the heated air temperature by sensing the ambient air and automatically regulating the flow of hot antifreeze through the heater core via the heater control valve, shouldn't it be placed outside of the heater box like where I found the broken-off piece instead of inside the heater box, right next to the core where the temperature is much greater that the ambient air inside the car? Answers anybody? Scientists? Master Yoda? Anyone?

Before:

After:

Upon removel of the heater box from the Volvo, my initial assessment is that all the external rubber seals are toast and need to be replaced, all screws and nuts need to be replaced, the box needs to be repainted, the blower motor needs to be fixed, and the heater core needs to be flushed and checked for leaks. We'll see what lies in store tomorrow as I crack the heater box open. Oh yeah - since I'll be repainting stuff, I think I'll also repaint the part of the heater control valve that sicks out of the firewall into the engine bay. Should I keep everything at the standard black, or should I dare go with a splash of color ... say red or yellow?