No heat, overheating

So I’ve never had a problem with the heat in the car, ever. It’s usually so hot I have to roll the windows down or put the dial half to a third of the way.

But two days ago I had to go to my final exam at 6pm, and it was the coldest night of the year so far. The car usually doesn’t take long to warm up, but it was taking longer than usual, yes I took into account that it was freezing outside. Well, I got about 3 miles down the road, and heater is still freezing and the car starts to overheat.

I didn’t drive it after that, just left it in the nearest parking lot and had someone pick me up and bring me. Well, the first thing I could think of would be the thermostat so I just replaced it. Took it for a test drive, and again the same thing. The wierd thing is if I shut it off and turn it back on it’s back to normal driving temps…does this make any sense??

I’ve noticed there’s no pressure in the hoses, theres no leaks so I can’t figure out why. I just replaced the timing belt, tensioner and waterpump with honda oem last month. So I can see my waterpump failing that quickly. If I open the radiator cap it’s still moving the water. I also noticed nothing is coming out from the bleeder valve if I open it. I did drain the coolant and put fresh coolant in, and it’s definitely moving through the piping.

It doesn’t sound like the fans are coming on either, not sure if that’s because it’s cold out right now(were supposed to have a blizzard tonight, and it sucks working out in the cold) but it should be activating if it’s “overheating” or whatever it’s doing.

What else could it be, radiator cap or temp switch on the thermostat housing. If its the switch is this the one±+Radiator&currentPage=1&categoryDisplayName=Cooling+%26+Heating&navValue=16300115&itemId=115-0&parentId=63-0

what kind of coolant did you use 50/50 or anything else?

I used 50/50

Ok now did you bleed the cooling system of air after you replaced the thermostat and did you put the thermostat in the correct direction there should be a steady stream of fluid coming from the bleeder valve when you open it and also does your radiator cap look in good condition.
Heres the bleeding procedure:
1.Loosen the air bleed bolt its located right below the Cam Cap on the left side and make sure the the radiator is full to the bottom of the fill neck wait for a steady flow without bubbles of fluid to come from the bleed bolt then tighten it back down(Have something to catch the coolant). 2. Then take the radiator cap off and start the engine then wait till the car gets to operating temp and if neccesary add coolant to bring the fluid level back to the filler neck. Then put the cap on and check for leaks. You may have to bleed it a couple of times depending on how much air is in the system.

Well, for some reason the heat decided to kick in finally. The hoses leading to the heater were cold before but now they finally got some warmth. Not sure if the air is as hot as it was before.

I’ve bleed the system before, when I did the water pump last month. The problem is, there’s nothing coming out of the bleeder valve like it was when I did the pump. I can take the whole bolt out and still nothing. I’ve been trying to bleed it through the cap as best as possible but we’ll see what happens. It’s getting too cold to work outside, suns going down and snow should be falling soon.

I guess the only other info I can give at this time is lower radiator hose is cold, and I’m not getting pressure out of any of the hoses…and yes, I put the thermostat in right. Also, has a steady idle.

Damn man I know how it is working on cars in the cold, not fun at all. That is really wierd that there is no flow of coolant coming from that bleeder. Could something maybe be clogged?

if the lower radiator hose is cold it sounds like you have a clog somewhere.

So what was the verdict? :bored:

sounds like heater core is cloged

this is correct. because coolant flows, or should flow, through the heater core before it reaches the t-stat. which means it wouldn’t matter if the t-stat were stuck.
hot coolant is pushed through the upper rad hose when the t-stat opens. it’s then cooled through the rad and pulled through the lower rad hose.
a cool lower rad hose is an indication of proper operation of the cooling system