Supposedly Overheating Yaris 1.0 Gls

[Legend-ary]

umm.. so I have been handed down a 1999 Yairs GLS 1.0 which had been off the road for almost 2 years. I have been working on it to clean it and make it roadworthy.

the car went on an MOT yesterday but they returned without it saying they cant perform it as its overheating. I was like uh-oh

I was surprised as I could hear the fan working very loudly and it would turn off but came back on instantly. The coolant temperature light wasn't on but he said all the pipes are pressurized and its not safe for them to conduct the test.

Now during the time I was working on the car [cleaning interior etc] I would often start the car and leave it running as it had been sitting for well over a year. All fluid levels were fine and never needed to top up anything. In 2 months I had only heard the fan once maybe twice but never so constantly like it was running in the testing station. The mechanic said the car has done too many miles so its not worth it and I should get rid of it.

So I got the car back and read a bit and here is the situation: The car starts with half a crank, green coolant light on, after 10-12 minutes of idling it will go away and stay off, the fan then kicked in and sounds like a jet engine, which I believe means its running on full speed. So either its off or on full speed. I understand there is a slowish speed it can operate on but thats not happening.

I figured I should start from checking weather thermostat is working or not. I did a cold start with radiator cap off and let the engine run, my standing is once the engine warms up, the thermostat will open and water will start swirling in the neck of the radiator. it didn't. The fan came on full speed, but water stayed still, just rising a bit and overflowing. I tried locating the thermostat by taking off the bottom radiator hose and the top one too from the engine side but there was no thermostat there. Its a Jap Yaris with 1.0 1SZ engine. Am I looking at the wrong place?

One more thing, while the dash was still showing the blue coolant light, water level rose up a couple of mm and overflowed through opening. Is that bad?

To make sure I fix this overheating issue, I have taken the radiator off and this is what it looks like so it is going to be replaced for sure.

I love my Yaris! even though I have never driven it on the road but working day in day out during lunches has made it very difficult for me to part with it without giving it a fair chance. Pleaseeee help me get this back on the road..

[Madasafish]

I suggest your Yaris radiator is furred up inside..

Thermostat location?

http://www.toyodiy.com/parts/p_E_2001_TOYOTA_YARIS_SCP10R-AGMGKW_1603.html

.When you have a new radiator report back.

BUT pressurisation is BAD: sounds like a cylinder head gasket has gone.. possibly...

[Legend-ary]

Hi Michael, new radiator and red coolant will be with me tomorrow so I will report back after installing and maybe make a video of the situation aswell. The link you posted, it did point me to thermostat but where is it located in a 1SZ engine? The diagrams don't match up and the two radiator pipes connect to the engine very close to each other. have a look at the image.

there are 3 sensors near where the bottom pipe goes in the engine [marked 1,2 and 3 in the image]. Is it possible 1SZ has a sensor based thermostat rather than mechanical one? where could it be?

[Madasafish]

Hi Zee

I never have removed a Yaris thermostat - so apologies. Haynes shows it mounted in the block at 2 above.