No heat in the cab!

-17degC this morning..... I usually have full cabin heat after about five minutes of idling/driving but this morning as the temperature gauge went up there was only cold air blowing into the cabin...no heat whatsoever.
Then the temperature gauge shot right up to the redline. I turned off the truck and let it cool for five minutes then drove home. The upper rad hose is hot the lower rad hose was barely cool not cold but definitely not warm

My first guess is to replace the thermostat… Does that sound about right?

I'll have more time to look at it after work today. Going to double check the coolant mix.

Edit: did finally get heat blowing into the cabin after about 45 min or so, after getting it parked and checking out the heat in the hoses some more.
Still, left it parked and took another vehicle to work for the day (thanks to kick-ass neighbours )

 

Nothing?
No suggestions or even smart ass remarks ?

I'm thinking I may have added a bit of water to my coolant back when my serpentine belt shredded the hose...and I didn't do a complete coolant change since.....

 

No heat from the heater is an indication of very low coolant (no coolant in the heater core), or no circulation(ice in the cooling system). Either one will result in overheating and possible engine damage. Check the coolant level and the freezing protection level.

 

Appreciate the reply.

I'm going to check the coolant mix tomorrow with my refractometer. I'm betting it's a bit diluted and froze a bit.

 

It wouldn’t hurt to replace the thermostat either. To me it sounds likes a stuck thermostat, but I don’t know the arrangement of cooling system.

 

Refractometer? That sounds complicated. I just use the $7 Auto Zone floaty thing.

 

I'd be up for that, but if I just need to top-up or replace the coolant then I'm cool with that too.

 

Recommendations are good. Possibilities:
-Check coolant level. This should ideally be done with the truck warm so the thermostat is open. If you are low on coolant and the thermostat is closed the core could be near empty not allowing the transfer of heat to the cab or cooling of the engine causing temp spikes. Of course you will then need to determine why you are low on coolant.
-Thermostat. If the thermostat is stuck in position or slow to respond, the truck may take a long time to heat up or over heat quickly.
-Waterpump. If your water pump is not circulating coolant like it should, no hot coolant will go through your heater core meaning no heat in the cab. Without circulating coolant, your engine temp will spike quickly. This could also be caused by a loose belt on the water pump.
-Heater core clogged. If you have not changed your coolant regularly, it could be the heater core has become clogged and inefficient at flowing coolant and transferring heat. Is the least likely as this would not affect engine operating temperature.

 

Maybe try this?
https://youtu.be/LD2LGkUycQg

 

I use it for checking specific gravity (basically, state of charge) in deep-cycle batteries, but it also reads the freezing point of ethylene glycol and propylene (sp?) glycol.
Pretty simple to use and way more accurate than any of the floaty thingys.

 

Awesome...thanks for this.
My serpentine belt did disintegrate many months ago and shredded a coolant hose, which I replaced and thinking back I probably only topped up the coolant with water at the time.

 

What did you figure out?

 

You have a big old air pocket in the system. Park with the nose up on a hill and run the truck up to operating temperature. Then massage the upper radiator hose while the engine is running.

A bright spot is that the air pocket with give you false high temperature readings and your engine probably didn't run hot at all.

 

I tested the coolant freezing point with my refractometer and it was -13degC. Morning of the "no heat" issue it was -17degC.
The level was also low, so as a quick fix (prior to doing a complete flush) I topped it up with Toyota spec coolant(see pic) ...which brought the freezing temp up a few deg but not good enuf.

I managed to take a pic thru the eye-piece of the refractometer with my phone...(see pic)

Suffice to say that I need to do a complete coolant flush/change or at the very least drain several litres out and top it off.

Today I'm tackling some trans/diff fluid changes first.....

 

Well I know one thing...it's pretty f#%&ing cold in Edmonton this weekend...

 

No way man, it was about plus 5-6degC today! Not too bad.
On the other hand... tomorrow is calling for a low of -23degC.

 

Holy shit.

 

Hey guys. I know this is an older thread but I found something so profound I figured I’d put it here to help others. I’ve attached a picture that I altered to try and show you what I found but I’m no artist so forgive me but you’ll get the idea….I bought a brand new 2018 Tacoma. From day 1 the heat was absolutely terrible. My dealer (complete thieves) said “It’s just how they are.” Yes…of course it is…I literally put 40 hours into finding the problem. The first thing I did was to listen when I adjusted the dial from hot to cold. I could indeed hear the actuator move. If I set it to cold, no problem…cold as ice. If I set it to hot….it would be warm at best and that’s after driving for 30 minutes or more. I could also hear the actuators operating when I adjusted the “mode” knob as well as “recirculate.” After this, I replaced the thermostat, flushed the system, replaced fan clutch as I just assumed the heater core wasn’t getting up to temperature. My truck only ever gets to 180 degrees on the hottest day so it does run pretty cool. Anyway, no change although my fan clutch had indeed been seized which I only discovered after putting the new one on and hearing how it’s “supposed” to sound. These are all things my dealer could’ve and should’ve done or at least checked but my dealer will ALWAYS find a reason to bill you even if they discovered nothing or that it was Toyotas fault so I avoid them like the plague. One day I just said “screw it,” I’m gonna take the dash apart to see if I was missing something. I knew the heater core was ok as I wasn’t losing coolant, couldn’t smell any in the cab and both hoses going in and out of it were hot. I started by removing the glovebox which actually turned out to be quite simple…less than 1/2 hour job maybe 8 bolts/screws in total. After it was out the problem just reached out and slapped me in the face. I’ll explain it as well as I can. If you look at the attached picture you’ll see the blend door actuator motor which is screwed onto the piece I drew.(The unit is all black, I just drew it in red so it sticks out better.) This piece is where the gear and cog are physically connected to the blend door lever. You’ll see there are 2 tabs sticking out. There are actually 3 but you can’t see them all from this angle. The top one, where the purple/pink arrow is, was never screwed in from the factory…so here’s what happens. When the unit is installed, it’s pushed up into place, the 2 bottom screws are put in as they’re the easiest to get to and then the top. Well if the top one doesn’t go into the proper position it jams up against the screw channel. This is not easy to see and the channel will still accept the screw so if you aren’t paying attention you’ll think all is well. This pushes the top of the units shroud down (it’s really thin flexible plastic.) and actually blocks the movement of the cog behind it at that point. So you’ll hear the actuator move but it’s really only moving half way!! Remember, this was never touched by anyone since I bought it so this is a factory defect. I hope this helps someone. It drove me crazy. I drove the truck all this time just thinking it was supposed to be that way.

 

Good find. So you repositioned the actuator and then were able to tighten the top screw completely? Glad you fixed it. That's bad the dealership was useless. I can say the heat in my 2007 is great, this is the first winter that I've had it.

 

Yep. Well…I had to use a heat gun to get the screw tab back into the proper position. It had been jammed in there for almost 5 years so it was permanently set in the wrong position. I honestly can’t complain. The truck is like the only constant in my life lol. I know when I hop in it, it’s gonna get me where I need to go. The reliability is just astonishing. I know that l make mistakes at my job so I can’t really fault Toyota for this one. It happens and this would be a mistake that the tech 100% had no idea he made. They would’ve had to get the truck up to temperature to test it properly because like I said, you could hear that the actuator was moving.