Overheating - No Codes - SOLVED - THANK YOU!!

Both of those items thermostat and coolant control valve or a good idea The coolant control valve usually will be making some funny noises but I guess if it wasn't working at all it would be making no noise so there should be a code for the coolant control or the three-way valve but who knows Don't know anything about the car I mean could it be clogged somewhere not the inverter system we're talking about the main cooling system here for the ice engine inverter system seems to be working fine I wouldn't be worried with it this is for your engine heat etc You have intermittent heat sounds to me like maybe somebody changed the coolant and they didn't get it bled well but there's no mention of a coolant change or any of that here so it's hard to speculate really

 

Radiator or heater core?? The radiator is located behind the grill - engine compartment, heater core is under the dash - inside the car.

 

Have you check Radiator Fan (could be failing)? ... If you are getting warm/hot air on low speed could be a culprit. On low speed or traffic, fan should kick in to compensate for cooling. If it doesn't then can contribute to over heating. If you installed catalytic converter shield recently, that could be causing it as well. Had this issue on my 2009 prius, for some reason the heat coming from the converter gets trap inside the shield (design flow) and triggers false overheat/hightemp indicator for me (No code). This went away when I remove and replace with a different converter shield brand.

 

If the red triangle was still on when you used the Autel scanner to read the codes, the scanner is not good enough to read all the trouble codes in your Prius. Is the red triangle still on? Read the first post, and then skip down to post #37 in the linked thread for information on scan tools: https://priuschat.com/index.php?posts/3246758

As far as the engine overheating, the first thing to do is check the coolant level in the radiator (you remove the metal cap) and in the plastic overflow bottle. Low coolant level will cause overheating of the engine and no or low heat in the cabin.

 

Am I on the right track.
No, not in my opinion. You're mixing up coolant circuits.

I check to see if my inverter pump was working
Your warning light is for the engine. The inverter pump is separate from the engine cooling circuit, and provides flow only for the inverter/electronics cooling circuit. The electric pump located next to the brake accumulator and master cylinder provides flow for the cabin heat, but rarely ever fails.

There is also intermittent cabin heat. I get a little heat at low speeds, when the coolant temp tends to be lower and no cabin heat at higher speeds when the coolant tends to be higher.
This clue is pretty important and usually means your coolant level is very low in the engine circuit. Check your radiator and overfow reservoir levels. Most likely it's pretty low. Not the white tank by the inverter, that's for the inverter circuit. Check the one at the front of the car.

Look for leak evidence under the car or on the back side of the engine water pump pulley. If the correct coolant is in the car, leakage will leave pink residue.

 

When the mechanic replaces the control valve & thermostat, ask him to look for sludge in your cooling system and report back. Sludge would indicate that someone placed gasket sealer in your cooling system.

Also keep and eye on both coolant bottles after the repair. If the system isn't properly 'burped' those levels will go down. Check them every fill-up for the next month or two. You don't want those coolant levels going to the bottom of the bottle.

Hope this helps...

 

I would go ahead and replace the thermostat and make sure that there is a belt on your water pump and that it's not slipping and see what that does before I start ripping into the coolant control valve and all that if it's not making a noise or doing anything adverse You can also touch all the hoses that go to the coolant control valve when the car is at temperature and see what you have that way too. Then of course you can sit there while it's warming up and see what the different hoses do as it warms up It just sounds like literally you're low on coolant these things are a pain to feel You feel it with a trickle through the metal capped orifice and I mean it can take 20 minutes to put a cord in You pour a little that goes down get sucked into the mess you poured up to the top of the filler neck again glug glug glug and goes down you do it again you'll do this 15 18 times till it finally gets up to the top of the filler neck and stays right there at the hole where it hits the hose to go to the overflow tank and it should sit there for 5 6 minutes without moving If it does add more coolant once you get it up to the top of the filler neck and it stays there for like 4 minutes then you put the cap on Make sure the jug is filled to the white marks that you see in the very bottom of the filler neck when you look down it they should be pink colored with fluid and go for a drive I bet you're not overheating now

 

Yep, fans kick on in city, stop n go traffic. If your traveling 60 mph down the highway, there's a 60 mph wind pushing through your radiator. You can check radiator shutters, if your car is so equipped. This also doesn't rule out sludge in your cooling system.

FWIW; I've got a CAT shield on mine; other than the exhaust tunnel getting a bit warmer in city, stop-n-go traffic - nothing else is affected.

 

Considering this is happening at highway speeds I would focus on low coolant, the thermostat and the engine water pump.

Check the coolant level now. Don’t drive it long at those engine temps or your problems will get much worse.

I agree. The radiator fans are not needed at highway speeds.

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It appears the primary engine cooling is very traditional, radiator, thermostat water pump, engine and back to radiator.



I would not do the water valve until the primary coolant system is checked and properly flushed. Flushing is tricky after a drain since you have to cycle the coolant heat storage system to get all the air out.

 

Be sure to read the flush procedure. The coolant heat storage tank is not open for flow when the engine is running.

Given you have air in the coolant system, the flush procedure includes using a bidirectional scanner like Techstream to manually open that flowpath.

You also need to verify how the coolant was lost, especially if a coolant drain was not done before this problem started.

 

This car should last you a long time 500,000 mi or so pretty easily usually most people get tired of the car before the car really lets them down seriously you know they got to have a payment something new keep up with the friends you know all that sort of thing