No heat,temp gauge rise

No heat this morning, blowing cold at all settings. Had heat last night.
At 28600, noticed maintenance required light on this morning, figure that means 30K service due. was not planning to go to dealer for this.
After about thirty miles today, in the rain, I noticed steam from under hood, thought it smoke at first, not smoke.
Fluids appear OK

Ideas?

 

stuck thermostat ? big anti-freeze leak ?

 

coolant level looks OK
where is that thermostat
any online diagrams on this?

 

Are we working with a 2015 truck ?
1GR-FE Cooling
Cooling System: Parts Location, On-Vehicle Inspection
Coolant: Replacement
Water Pump: Removal, Inspection
Water Pump: Installation
Thermostat: Removal, Inspection
Thermostat: Installation
Fan: Inspection
Radiator: Components
Radiator: On-Vehicle Inspection, On-Vehicle Cleaning
Radiator: Removal
Radiator: Disassembly, Inspection, Reassembly
Radiator: Installation

 

Not related to your problem, but the Maint Req light usually comes on when your oil change interval is up.

 

head gasket leak? or thermostat

 

got trouble here. spotted couple dried pink spots on oil filter, and some very slight pink tinge fluid, small amount, sitting in cupped area. opened up the cover, some of the white foamy cover liner appears like pulled away, and down in the recesses is area that has the fuzzy insulation now pink tinged with wires un covered, first thought is rodent attack.

 

you sir, have a rodent problem

 

does look like rodent chew, but , is there a hose in this area with coolant fluid, that the rodent has chewed thru to spatter all the pink

 

the hose in the picture next to the chewed wire loom. start your truck and turn your heater on full and check if water come out of it

 

I believe the line circled in red is the coolant line that runs through the throttle body. Definitely looks chewed through. When you say the coolant level looks fine, do you mean in the overflow bottle or actually in the radiator? It is possible for the radiator to be empty and the overflow bottle to still be full. Remove the radiator cap and check with the engine cool.

 

I'm with him. Your reservoir may start consuming more coolant as you continue to drive. If your dealer is 30 minutes or more away, buy a gallon of distilled water to keep with you.

 

That line does indeed look like the one that connects to the throttle body. I'm betting that's the issue.

Most people don't know it, but the coolant overflow tank is exactly that....an OVERFLOW. It's where excess coolant goes and does NOT indicate how full your radiator is or the rest of your cooling system. The neat thing about the cooling system is it's completely sealed and holds a certain amount of fluid. When everything heats up the materials expand and naturally, some of that coolant is pushed OUT of the system, into the coolant overflow tank. As things cool down, the system creates a vacuum and sucks some of it back in.

However, in the case of Mickey Mouse up there...you have a breach in the system. This means coolant exits that hole and worse yet, air gets IN through that hole and into the system. The really shitty thing is that hole screws up the system's ability to create a vacuum to pull coolant in from the tank. So even though that tank is full, your system is likely VERY low on coolant. You'll run the truck, lose coolant out of that hose as you drive, and then when the car cools it sucks air in that hole instead of pulling coolant from the tank. Let the truck cool over night and then open the radiator cap and pour in some coolant or distilled water till it's filled to the top.

Water has excellent cooling properties but it boils at a low temperature. Coolant raises the boiling temp a bit but the real magic is the pressure of the system. Most systems run anywhere from 10-16psi for the cooling system. This raises the boiling point of water nearly 50 degrees and allows the water to cool the engine. Once the water boils it doesn't cool for shit. And with that leak in your hose, your system isn't reaching optimal pressure so I'm sure it's not cooling properly.

Having owned a few RX7s I'm intimately familiar with cooling systems.

 

poured a gallon of distilled water into the radiator and took to Toyota for diagnostic.

 

Wow....it took a GALLON?!?! Holy shit...you were bone dry!

 

Honda Rodent Tape, its spicy electrical tape
https://www.amazon.com/Honda-4019-2317-Rodent-Tape/dp/B00AJTG3N0

 

Outstanding. This is hilarious.

 

i'll second the hilarity of dang varmints chewing my hose and drinking all my coolant, and chomping my wire harness, toyota diagnostic indicates wires all good, just plastic repair needed, the throttle body hose and two clamps need replace, and they under the plenum/manifold, so complicates fix in hours...esti 544$. don't have the time to learn how to fix myself, so gotta pay

 

Not that hard to replace hoses. Just have to disconnect the throttle body/manifold which isn't extremely difficult. But if you don't have any time, that's a pretty hefty price. Least you caught the issue before it was too late.

 

I had an MR2, so I know the pain as well.