562,

You are pointing at the fan sensor in the first photo.

Chris

 

Thanks alot buddy! I kind of figured it was that one since it was on the thermostat but I started to scratch my head when I saw only 1 wire. Usually there are 2

 

btw what is the sensor on the second picture?

 

Man this thread is dead. even with pictures I only get 1 response -_-

 

Patience is a virtue . The one nearest the distributor is the thermoswitch and the other one is the coolant temperature sensor.

 

Yeah I should have waited but I got inpatient lol but thanks!

I have a problem with my fan turning on so I figured I'll check to see if it works. So I manually jumped it to the battery and it works. So I'm trying to figure out if its the sensor or the relay.

*How do you jump the fan switch so that it automatically turns on? Usually on my civic I would just take a paper clip, fold it in half and stick it into the two pins and turn the car on. But for the toyota it looks like theres only 1 pin for the fan connector.

btw the fan does turn on only when I turn on the a/c. Is that weird? It turns on and then turns off then like 30 secs later it turns back on.

Please help me! Thanks in advance

 

I also tried searching the forums by using keywords like: test fan or radiator fan or cooling problems but its hard finding a particular problem.

 

562,

If I'm not mistaken, the fan should run when the wire is diconnected from the sending unit. If it doesn't kick on imediately, give it a minute.

Chris

 

Really? thats a pretty cool feature from Toyota. I was gonna get a wire and stick it into the fan switch harness and ground the other end to the chasis or something to see if the fan turns on. Gotta try this tomorrow. Thanks and wish me luck!

 

Well I took of the fan switch and turn the car on and it worked! So now I can eliminate the culprit:

Fan works
Relay works
Harness works

Only 2 culprits left:
Thermostat
Fan sensor

What do you guys think it is? The top hose is super hot, the bottom hose is a little hot and there's a little bit of smoke coming from my radiator.

*What is bothering me is how I can drive around the block for around 5 mins and not hear the fan turn on. The temperature gauge is a little less than half way. Is that unusual? or is the engine coolant temperature just not hot enough to activate the fan switch?

 

562,

I may have missed it, but I don't see where you ever stated a problem? My temp guage is a little different, but runs very near where yours is, just below half way. I almost never hear my fan run, only noticed a few times and then not for long. As long as the car is running cool, I would think you are good to go.

Chris

 

Sorry I didn't make it clear. I am having trouble with my fan not turning on when its suppose to turn on. I am just concerned because I idle the car for like 20 mins, take it for a drive and come back to see if the fan turns on but it doesn't and my temperature gauge is normal. I was just wondering if this was possible for the temperature to stay down even if the fan isn't turning on.

 

The fan switch is located in the outlet from the radiator. Coolant goes into the radiator at the top and comes out cooled at the bottom. If the *cooled* water is hot enough it will trigger the fan switch. Meaning that the radiator fan will not turn on until the bottom hose from the radiator is hot enough.

The temperature sending unit for the gauge on the instrument cluster is located at the pipe going from water pump to cylinder head and thus shows temperature of the coolant circulating in the engine.

If your bottom radiator hose never gets hot than perhaps the radiator is seriously clogged? Do you have a lot of coolant going into the overflow bottle when it gets hot? Due to pressure build-up. Is the top hose hard due to high coolant pressure?

 

If your bottom radiator hose never gets hot than perhaps the radiator is seriously clogged? Do you have a lot of coolant going into the overflow bottle when it gets hot? Due to pressure build-up. Is the top hose hard due to high coolant pressure?

The bottom radiator hose does get hot after a while so I'm guessing its not clogged. There is no hot coolant shooting back into the reservoir tank therefore its not over heating. The top hose is soft and super hot.

 

Here are more pictures:

I found out that there is a couple hair line cracks on the top of the radiator. This explains why a little bit of steam is coming out which may cool down the temperature of the coolant. So I bought a new radiator

Old

New

I also wanted to figure out why there were hairline cracks on the top so I had to investigate whether it was due to high pressure from the fan not working or was the radiator just too old and needs replacing.

1. I started by testing the fan itself by hot wiring it to the battery and it works
2. Then I tested the relay and the fan sensor harness by unplugging it from the fan sensor and it spuns so it works
3. I checked the thermostat to see if it opens and closes

Closed:

Open:

And this is the new radiator installed:

I still wasn't able to check the last thing, the fan sensor itself because it was so dam hard to try and break free. I thought I might break the sensor so I left it on.

*Is the fan sensor durable enough that its not typical to replace it often? I would think its pretty durable do to the fact that the sensor is made to withstand high heat coming from the radiator.

*Should I replace the fan sensor just in case? I don't know what caused the high pressure crack on my old radiator but I don't want it happening again to my new radiator either.

Let me know what you think

 

The radiator is designed to cool the engine using the airflow that is generated just from the car's movement. The radiator fan is only there for situations when that airflow is not enough, e.g. traffic jams, very high ambient temperature combined with high engine load and/or low speed. As soon as you drive the car, the radiator fan is *less* likely to need to operate.
I do not see any reason to replace the fan sensor switch. Especielly if it is very tight. You just might break it off, having to drill it out and all sorts of misery.

When it comes to regulating pressure in the radiator, it is done by the spring loaded cap. If the pressure gets too high, the coolant will sip past the cap and into the overflow tank. Unless you have an incorrect cap this should not be a problem. For the most part when there is a problem with the cap, it is not holding pressure so the coolant overflows extensively or boils.

 

Yes thank you very much for the information. I actually experienced the coolant shooting into my reservoir tank on my civic because of a stuck thermostat haha. btw I am happy today. I left the car running for about 30 mins and felt the bottom hose to see if it was hot. It was hot to the point where I couldn't hold it but the fan still didn't activate. Then I decided to let it sit for 1 more minute and the fan turned on!! I was so happy

 

btw I drove the car around and it runs great! No over heating problems! I also drove to a local autozone and bought some parts to tune up my car. I will keep you guys posted tomorrow. Maybe I should create a new thread to show what I have done to my corolla including buffing, polishing, waxing, tune up, etc..

 

562,

Glad everything is working for you. For those who search this thread in the future, the check for the ECT (engine coolant temperature) switch is quite simple. To test, you disconnect the wire from the end and then check for continuity between the prong of the ECT and the body of the ECT. When cool (below 180 degrees), there should be continuity, when hot (above 180 degrees) there should be no continuity.

Chris