All of a sudden, my heat started blowing cold air and the van was overheating. Weird, huh?
The radiator was full, so I started trying to figure out what else it could be. Water pump, thermostat, clogged heater core, etc.
The thermostat wouldn’t affect the heat, so I eliminated that possibility. It had to be that stuff wasn’t circulating at all, cause it if was there would be hot coolant in the heater core and cool coolant in the engine, ya know?
Water pumps are a pain in the ass, so I put that possibility off and decided it must be blocked up somewhere. On my way to the store to get a flush kit I talked to my little sister (who is, truly, a mechanical genius) and she blew that theory out of the water by saying that if the system were plugged and the water pump were working the pressure would have caused it to blow a hose.
Then it must be the water pump, right? When I got to the store I pulled out my handy Chiltons, which advised me of three ways to check water pump functionality. By all indications, my water pump was working. So I had logically eliminated all possible problems. I tried standing in front of the auto parts store with my hood open and my Chilton’s out, but since I’m in Alaska no one assumed I didn’t know what I was doing and tried to help me.
When in doubt I check my email. It’s like a stress displacement behavior or something. So I checked my email and found a lot of good advice from the vandwellers list. Several people advised changing the thermostat, checking my fluid, flushing the sytem, etc. All of which I’d logically eliminated. Then one guy mentioned that sometimes van’s can have air bubbles (which makes sense since the heater core is probably at about the highest point in the system, although it really might not be in this van, I dunno) and recommended parking on a hill to burp it. Hell, I’ll try anything once. I parked on a hill. I lovingly patted my radiator. I gave it a few good kicks in case that’s what it needed to dislodge an air bubble, and…. it burped up a big air bubble. Crazy. I filled it up with water (why waste cash on dex cool stuff when I’ll probably hafta drain the system to fix whatever’s leaking anyways) and the heater works again.
I haven’t driven far enough to know if the overheating is fixed, but I’m about to.
The thermostat WILL cause the heater to act up, as the water will only stay in the engine block if the thermostat stays closed. The water must circulate to cool and the thermostat is the number one culprit.
No, if the thermostat is closed the coolant will still circulate through the heater core. If it’s stuck open in the cold it’ll never warm up, which will affect the heater, but then the engine would be running cold, not overheating.
Think what you like.
It’s not what I like, it’s logic: when it’s twenty below and your thermostat stays closed, your defroster still blows hot air, right? That’s cause the thermostat just cuts out the radiator, not the heater core.