Radiator dashboard lights ON...what does it mean

Based on the information provided, the radiator dashboard light and the check engine light coming on at higher speeds and then disappearing after the car cools down are indicative of an overheating engine issue.
Here's a breakdown of the possible causes and fixes:
Possible Causes:

• Low Coolant Level: A common reason for overheating. This could be due to a leak in the system or just needing a top-up.
• Faulty Thermostat: The thermostat regulates coolant flow to the radiator. If stuck closed, it can cause the engine to overheat, especially under load.
• Water Pump Malfunction: The water pump is responsible for circulating coolant. A failing or broken water pump can lead to overheating.
• Radiator Fan Issues: The radiator fan helps cool the coolant when the car is stationary or moving slowly. A faulty fan or fan motor can contribute to overheating.
• Clogged or Failing Radiator: The radiator may be blocked internally, or it may be leaking, preventing adequate cooling.
• Blown Head Gasket: Exhaust gases leaking into the cooling system can lead to overheating and increased pressure.

Troubleshooting and Fixes:

1. Check Coolant Level:
   • Allow the engine to cool completely.
   • Locate the coolant reservoir (usually a translucent plastic tank).
   • Check the coolant level against the markings on the reservoir (min and max).
   • If the level is low, add the correct type of coolant (refer to your owner's manual for the recommended type). Use a 50/50 mix of coolant and distilled water.
2. Inspect for Coolant Leaks:
   • Check the radiator, hoses, water pump area, and under the car for signs of leaks (puddles or drips).
   • If leaks are found, repair or replace the faulty component(s).
3. Check Radiator Cap:
   • Inspect the radiator cap for damage or a loose fit. A faulty cap can cause pressure loss in the cooling system.
4. Check Radiator Fan Operation:
   • With the engine running and at operating temperature, check if the radiator fan(s) are engaging. If they don't, there could be an issue with the fan motor or related electrical circuit.
5. Monitor the Temperature Gauge:
   • Pay close attention to the engine temperature gauge while driving.
   • If the temperature gauge starts to rise quickly or enters the red zone, stop the car and let it cool down.
6. Consider a Thermostat Replacement: If other simple checks don't solve the issue, a faulty thermostat may be the culprit.
7. Seek Professional Help: If you're unable to diagnose or fix the problem yourself, it's recommended to seek help from a qualified mechanic.

Important Notes:

• Do not open the radiator cap while the engine is hot. This can release scalding coolant and cause burns.
• Overheating can cause serious damage to the engine. It's important to address this problem promptly.
• If the check engine light comes on alongside the radiator light, consider getting the error code scanned by a mechanic. This might give a more specific diagnosis of the issue.

 

Cooling fan issue is unlikely; 60+ mph wind flowing through the radiator should be sufficient. Other than that; @StarCaller is correct.
You need to get us the error code and history of the car; for us to be more helpful.
If everything else is running correctly and your up to date on ALL OEM required maintenance - I'd replace the electronic ICE water pump and thermostat. They're known to slow down and fail around 150K miles. If you bought this car used, someone could've put stop leak into to coolant to cover up a head gasket problem. This would clog up your cooling system, causing cooling system issues when the engine is under load.

Hope this helps....

 

With this engine model the 2z FX whatever You're headed for a whole lot of fun

 

Blue is your ICE coolant
Red is your EV coolant
Yellow is your brake fluid.

Refill your blue marked tank to the ascribed line with red coolant. Make sure it's Toyota long life compatible. Keep and eye on it for the next couple of weeks. It shouldn't keep going down - that means that you have other issues....

 

If you are smart, you'll only use the Toyota fluid.
Mixing the fluids can cause it to jell... not good!
The cost is so close, it's not worth the risk to use anything else...

 

Ideally, I would use Toyota OEM coolant - Not good to mix and match coolant. I've seen chemical reactions when people do that.
This claims to be compatible.
PEAK Original Equipment Technology Asian Vehicles Red, Pink Antifreeze and Coolant Ready-To-Use

FWIW: The EV coolant is the same as the ICE coolant.

 

Just editorial:
ICE = Engine
EV = Inverter

Maybe an air freshener tree.
Then from a Toyota dealership: Toyota Super Long Life Coolant. It comes pre-diluted. This is what you need for both Engine and Inverter coolant reservoirs.

Your avatar says 2010, but this issue is with a 2012? Just get it, or?

Do you get any shaking/knocking, starting when the car's sat overnight?

 

Yes. Add the same coolant to each tank to raise the level indicated on the tank body.

 

This is explained in your owner's manual. If it's missing you can download pdf, one source being Toyota Tech Info website (just google), in the "Manuals" section.

I've attached an excerpt, just the relevant pages:

 

Better than just googling it, we've got a whole page for that: Toyota Service Information and Where To Find It | PriusChat

A lot of the more detailed technical literature on TIS is in the subscription portion, but the owners' manuals are right out there for anybody.

 

Seriously, for just Owner's Manuals?

 

For the little bit you're going to be adding right now to you find out your engine's going to blow up or whatever's going on You could just actually add that clear stuff we call water won't hurt a thing I don't think you're in Alaska. Therefore you don't have to waste any money running around buying fluid just take a little bit of water like from a water bottle let you drink from and pour it into the container until you bring it to the full line that'll mix with the mess in there and it'll still be red pink whatever Do the same thing to the other one but it right on the full market it's clearly marked with a line and then go on about your day and see how long it takes for the one that's on the right side of the car when you're sitting in the seat That's your ice engine radiator cooling system see how long it takes that one to go down The other one is for the inverter generally it doesn't go down It stays pretty consistent there's generally never a leak over there just to pump stops working The ice engine when it starts to go down you start get that rattling and all that noisy nonsense that's water seeping through the head gasket putting out one of the cylinder fires That's what water does it puts out fires your spark plug is a fire You can't put it out and expect it to be a vicious fire at both at the same time.

 

That's wonderful stuff You can also get any of the Asian red nonsense at any of the Stores you frequent. Wa mart etc. I mean if the Toyota dealer is convenient and they're giving you a reasonable price by the gallon or whatever it is I guess no problem but I don't know any Toyota dealer I don't know any car dealer that does anything like that in this world especially today you may think you're getting a deal but generally not any kind of way. The coolant is going to be the least of the problems in your car as will the oil brand seriously not the weight and all of that I'm talking brands here Toyota coolant versus peak nothing to discuss other than price and how far you might have to drive to get it The Toyota dealers usually way out on the outskirts of town where all the other car dealers are on car dealer row right but targets right here in front of me I'll take the peak thank you sir no difference nothing to discuss It's all in your mind The day you have a failure from the brand of oil or coolant is the day something else will have to happen because that's just not a thing