Engine light came on but seems to run fine

[naossoan]

Hi guys got a question for you.

I was out teaching my cousin how to drive stick on my 07 yaris 3dr hatch when I noticed the engine light came on for apparently no reason. The engine seemed to be running fine. So I got her to pop the hood so I could take a quick look.

Once opening it up I could feel a fair bit of heat coming off the engine and the coolant was actually bubbling out of the coolant reservoir like the overflow one. So I was like well shit that's not so good and shut the engine down to cool off.

I waited about 20 minutes for it to cool down then started it back up a and drove home. It seemed to drive just fine.

Then when I got home I looked online and found there should be a coolant temperature light that comes on if it's too hot, but that didn't come on. it was the orange engine light on the left side of the cluster that came on.

Now, when we were driving it was very stop and go ina parking lot with quite a bit of idling for maybe an hour and a half.

Should the fan not come on to keep it from over heating? Why would the engine light come on if it was indeed overheating but not coolant light?

What should I do? My dad knows a guy that works ata local garage that can probably run that diagnostic tool for me for free so I'm going to do that Monday to see what the code actually is... but what else?

It wasn't even hot out, like 20 Celsius.

[CTScott]

You really need to have the code read, otherwise it is just a random guess. It definitely sounds like you overheated, and the fan should have been running. If it was not, there may be a problem with the fan itself, the relay that drives it, or the fuse that feeds it.

[naossoan]

Thanks for your input.

I'm fairly sure its not the thermostat or the temperature sensor because when I went to start the car later on after it had an hour or more to cool down the light that shows the coolant temperature is low was on, as it always is when I start the car for the first time of the day or whatever. Unless its a different sensor for the low than it is for the high but I don't see why that would be the case.

My friend said I should start the car with the cap off of the radiator to see if the coolant is bubbling. He said if it is then there is a leak somewhere and air is getting into the system and I may need to get a new radiator installed.

I've never heard of this test before. Is that true?

[BLH]

When you first started the car.
Did the Red Overheat indicator momentarily light?
My 2007 Sedan does. I believe there is a indicator check during startup.

[naossoan]

Nope I didn't see any indicator things, only orange engine light.

[auxmike]

Look into the Scangage II device. It was $159USD at the time I bought it 4 years ago. It will tell you exact temp and what the code is. The fan should come on at 202F. I think the green temp light goes out @ 137F.

[CTScott]

Thanks for your input.

I'm fairly sure its not the thermostat or the temperature sensor because when I went to start the car later on after it had an hour or more to cool down the light that shows the coolant temperature is low was on, as it always is when I start the car for the first time of the day or whatever. Unless its a different sensor for the low than it is for the high but I don't see why that would be the case.

My friend said I should start the car with the cap off of the radiator to see if the coolant is bubbling. He said if it is then there is a leak somewhere and air is getting into the system and I may need to get a new radiator installed.

I've never heard of this test before. Is that true?


Yes. starting the car with the cap off and watching for bubbling will tell you if there is air in the system. If you have a leak, you will be losing fluid, so when you remove the cap, you will need to add fluid.

[naossoan]

Turns out a 30A fuse blew and the shop said its for the cooling fan which explains why it overheated....but why it blew in the first place I don't know. Apparently neither Napa nor Lordco carries the right fuse so gotta buy it from the dealer. Sigh.