Warming up My Tundra

I must be tripping or losing my mind!!!

Well it finally got cold enough to run the heater. In the past when warming up the truck I’ve always just went outside, started it up, went back inside, and let it warm up for 10 or 15 minutes and it was always nice and warm afterwards.

Here lately its totally different or at least I think it is, after running for a little while it’s still blowing cold until I drive it a little bit even though the temp gauge is showing that it’s warmed up. My driveway is approximately 400’ long, by the time I get to the end of it it’s blowing hot air.

I’m absolutely clueless….maybe my age is catching up to me.

 

Thermostat might be stuck open taking the coolant much longer to warm up and give you hot air. My Tacoma has this issue and I have to drive it quite a while before it gets warm. Easy swap you can do in your driveway lots of YouTube videos on it.

 

Check your coolant level. Sounds like your a little low, and the heater core isn't getting fluid at idle. When you start driving, the revs increase, and some coolant circulates into the heater core giving you heat. You're probably not getting as much heat as you used to as well, right?

 

I’ll check the level. In regard to the heat, it’s normal once it starts heating. Thx

 

Burping the cooling system will help a lot. Any work on the cooling system since you used the heat last year?
Park diagonally on a hill with your rad cap at the highest point. Let it warm up (thermostat open) and randomly rev the engine, tap those heater lines, squeeze the upper rad hose. A lot of air came out of mine. Works best with one of those attachable funnels, so you don't spit coolant everywhere.
There is a small bleed by on the thermostat as well that needs to be clocked in the 12:00/top position, if your feeling energetic and want to start digging deep.
Just my 2cents, live in Michigan, and depend on heat and defrost.
I'll see if I can dig up some links for you when I am at home in front of my shop computer.

 

Same thing this morning, warmed up for 15 minutes and it was blowing cold air, by the time I got to the end of my driveway it was like a light switch was flipped on, started blowing hot air like I think it used to do.

I checked the fluid/antifreeze level today, it’s good. No work has been done on the cooling system so I’m on the fence in regard to the system might need burping, don’t understand how air could have gotten into a basically closed loop system unless it is somehow how got opened up??

I’m scratching my head and butt over this one but it’s definitely not a show stopper.

Happy Hoildays everyone!!!!!!

 

The cooling system is not exactly closed. Once a certain pressure is reached the radiator cap opens and coolant is released to the reservoir which is open to air. Too much and it’s wasted overboard. When the coolant next cools and contracts coolant can be sucked back into the radiator from the reservoir.

 

So would you lean towards a new rad cap?

 

No

 

Make sure it’s topped off with coolant and change the thermostat.

 

My vote is t-stat is bad. Replace it with the jiggle valve @ 12:00 position. I would also replace the radiator cap, and only recommend OEM for both parts. Burp it well as @BroHon stated. You should be golden after that.

 

I've done/replaced:
Radiator
Fan blade
Fan clutch
Fan bearing bracket
Upper and lower hoses
Cap
Valve on the firewall
Thermostat...
Thermostat wasn't OEM, was a 170deg, and was prior to me knowing about the giggle valve. I still haven't opened it back up to check it. And the truck runs 190-200 in the summer in spite if the 170 thermostat.
But through all that one thing was clear to me. These trucks have stubborn air pockets in them that require burping/on an incline in order to get decent heat.
EDIT: If the thermostat was sticking wouldn't the engine run hot? Maybe it's sticking enough to keep engine heat under control but not enough flow to reach the heater core? And then when throttle is applied, flow pressure pops it the rest of the way open and full flow is released.

 

A thermostat generally fails to the open position, allowing coolant to flow continuously regardless of temperature.

Did you remove the radiator cap and check the coolant level in the radiator or did you just check the level in the reservoir? If the level is good in the radiator, I'd do what @BroHon suggested: put the truck on an incline with the front higher than the rear, run the engine, and burp the system. Those special-made funnels look like they'd make the job easier, but you can certainly do it without.

 

Could OPs problem be blend door related?

 

Or potentially cable lubrication. Like, if he's jumping in truck and cranking the heat control up, but it's taking time to catch up, maybe cable is sticking or binding.

If he's jumping in the truck and not touching any controls, I doubt it's in the vents, unless the blend door naturally closes when truck is OFF.

 

What exactly is the “jiggle valve 12:00 position”, I’m not familiar with that terminology???

thx, Griff

 

This little fella right here

 

As BroHon shows in the image, it's the pin on the thermostat. It has to be oriented at the 12:00 o'clock position for the system to function properly. I believe your t-stat is failing and/or air not purged well.



This is what it looks like installed. Let us know what your remedy is.

 

They're installed and positioned at 12 o'clock to prevent air lock and allow any bubbles/air to escape.

 

Anywhere from 11 - 1 o’clock will work for the jiggle valve, but it is best to aim for high noon.

 

Got it!!

 

Okay guys, the pictures of the “jiggle valve” does not match up to what I have in my 4.0 V6, this is a 1 piece until which includes the housing.

See the attached photo of the one I swapped out today…it did not appear to be stuck open. Picked one up from the local Toyo dealership.

This did not resolve my issue….same dang thing. May have to look at burping the system if it applies to a v6…..more to come.

 

Most of us have 4.7s and don’t know much about the V-6. That thermostat is alien technology to us V-8 guys.

 

Only thing I can think of at this point is maybe flush out your heater core. Maybe some gunk got in there and is limiting flow to your heater.

 

Or upgrade the heater core if possible. My truck has an upgraded heater core as part of the “all weather” package I believe. Supposedly a heavy duty core according to the brochure.

 

Sorry, my bad, I didn't even look and see you have the V6 flavor
That's quite the contraption

 

I’ve been fiddling with cars and trucks for 40 years and have never seen a set up like this either.

 

Yeah, purging the system of air applies to all makes/models of vehicles. Some cooling system designs just do a better job of self purging -- others, not so much.

That 4.0 V6 thermostat is new to me too. By its design it looks like it can only be installed one way, so the orientation of a "jiggle"/bleed valve (if it has one) would be irrelevant.

 

Your upgraded heater is a block heater designed to aid with starting.

 

Where is this mystical block heater you speak of? I haven’t seen it on the underside of my engine block or is it mounted elsewhere?