Heater blows cold at idle

I end up spending a fair amount of time stationary. For a few weeks in the winter we can average 0 degrees fahrenheit with some weeks -20. My issue is when I'm not driving the motor cools down so much the heater quits and I'll have to sit there with my foot on the throttle just to keep the motor at temp. Anyone know if any fix?

 

Block off part of the radiator in the winter

 

Check your fluid level in your radiator, cold air at idle is a classic sign of low coolant level

 

...it's really that simple. Feel like an idiot.

 

It's fine driving, then I'll park it, motor temp drops, heater quits. I like the idea covering part of the radiator but I also don't want to be zip-tieing cardboard under my truck in sub zero temps.

 

Engine temp and heater/blower temp are two different things.
These are things that were I dealt with from long ago.

Assuming your talking about the 2018 DCSB then you have a vacuum leak that cannot are not moving/hold the correct doors.

So at idol (low revs) you have low vac that doesn't move/hold the doors you picked, and when your driving (high revs) you have high vac does that.
Take it to the dealer and let them find it.

 

The blend and mode are vacuum actuated and not electronic? Color me surprised


Edit: just look it up on rockauto. They're electronic. Who told u they were vacuum?

 

You say "when I'm not driving the motor cools down". Do you know that because you see the engine heat gauge drop in temperature? Or because your heater stops outputting heat? If it's the first one, post#3 could be the solution. If not, off to the dealer. You shouldn't have to put cardboard in front of your rad. Your not driving a 20 year old diesel.

 

Trust me... the Tacoma and my 1976 Chevy C10 have identical heater controls. I asked my dad....

 

At first I thought u were saying they were vacuum lol. I was like no fuckin way!

 

Just making a funny...

 

I'm exhausted. I don't even know which color is up anymore.

 

Wait until you start hearing colors and seeing an engine sound...
That's when you call it a night.

 

Luckily enough I've avoided that so far!

 

Everything is fine driving and it seems to blow hot while it's warming up too. Then I'll park and the motor temp will drop to the yellow arrow, and it will start blowing cold. It could be blowing 60 to 70 but when it's -20 outside it feels like the ac is on.

 

hmmm...my first guess would be a bubble in the coolant since it works while driving. In park there is less air flow over the radiator than while driving but the water pump isn't flowing as much. Put the front end on ramps and burp the radiator, squeeze hoses too. Do this with the temp on max heat too to open up the heater core...give it some slight revs to get the coolant flowing and move the air out as well.

 

Might look at the cooling system thermostat. Could be stuck open.

 

I'm betting a bumble, I had the same thing happen with a buddies xterra I used to own

 

I agree with this.

 

Pulled on out once and found a pull tab stuck in it. And no, I have no idea how that one happened.