Last week my heat quit working and Im hoping someone can help regarding this.

Things to note...

The day before it quit working I used the heat in the morning and was working fine, later I used the AC which also worked fine.

Next day I leave in the morning and I hear a pretty loud sloshing sound around the heater core area(which ive heard many times in the past although not as loud), noticed heat wasnt working.

Coolant is full, t-stat seems to be working but I havnt actually tested it. Wouldnt it overheat if it were the thermostat?

Blend doors/ diverters/ whatever theyre all called are all working.

Developed a horrible screeching sound from the alternator the same day I believe but I dont think its related. Well, now (literally just now) im wondering if it could be the water pump? Again tho, wouldnt it overheat if the water pump wasnt working?

AC still blows very cold.

Changing the temp with the slider has no effect, just blows cold.

I think thats it, any ideas? Whats next?

 

Heater core could be plugged up... But no, if the water pump is going bad, it wouldn't necessarily overheat.

 

So lets say its malfunctioned and not circulating coolant properly. There would be some change in temperature if I moved the slider to hot? Otherwise the only other scenario would be complete failure of the water pump which would cause overheating?

 

Another thing I want to mention (if its of any importance) is that the coolant steadily rises to 178 and stays there as its done for as long as I can remember.

 

Turned out to be a plugged heater core and the loud squeaking was a dried up water pump.

Word of caution... When blowing into the core with 300+psi of air, shield yourself from the gunk and whatnot thats gonna explode with the power of 10 nuclear bombs.. LOL My poor garage...

 

Wow, glad to hear you got it figured out. Sorry about your messy garage!