Coolant Sensor

[ratt]

Can someone tell me where to find the coolant sensor on a 2002 is 200 as i need to check it out for a possible fault?

[Dean1309]

Hi ratt,

The temperature coolant sensor is located on the drivers side of the radiator, at the bottom of the rad, it has a white plug and is clearly visible if you were to look down behind the radiator.

 

[ratt]

Hi Dean,

Thanks for the reply, i'd been trolling the internet and came up against conflicting opinions. I just need clarification on what i see when looking down at the bottom of the radiator: yes there is a sensor but with a black plug (no biggy i think), but i've also come across a blog that says it is fitted on the cylinder head right hand side in a very awkward place.

[Dean1309]

Hi Ratt,

Back in June I had the same issue with my lex, the car started to overheat, the cause of it was a blown radiator, I had to change out the radiator,  the temperature switch and the thermostat at the same time.

It is definitely at the bottom drivers side of the radiator, you can unbolt it, plug the hole with you thumb and screw the new one in, top up the coolant and plug in the connector. job done :)

[ratt]

Hi Dean,

 It makes me smile to think i'll get away with the job this easy, but on your assertion that this is the one i'm gonna give it a go. i'll let you know how it pans out.

[Dean1309]

Only thing I cant remember is what size bolt the temperature sensor is, think it might be a 18 or 19mm but dont quote me on that.

[Britprius]

I think Dean is referring to the fan sensor switch that is in the bottom of the radiator. The sensor for the temperature gauge, and reference for the engine ECU will be in the block or cylinder head.

John.

[Dean1309]

Actually Britprius is correct, I was referring to the fan sensor switch, I stand corrected my mistake.

i would also be interested in where this is, my temp gauge has been playing up since my car over heated, temp gauge gets up to normal temp, but after long drives 50 ish miles, the gauge goes right back to cold again, and then goes back to normal/middle again, I have bled and bled the system and cannot find any bubbles/ air locks in the system. Really hope its not head gasket. As stated above I replaced the thermostat, fan switch, and rad at the same time.

[ratt]

Hi Dean,

So it is fitted on the right side of the Cylinder Head, it's not a bad job: alternator off first, then the cowling behind it and you will see the sensor with a green terminal block, once unplugged i found it best to break off the long plastic connector (a little tap with hammer and heavy screwdriver), this allows a direct fit for a 19mm socket onto the unsubstantial brass sensor---out and new one in.

Thank you to all replies.

[Dean1309]

Hi Ratt, 

That's perfect, thank you. 

I hope changing this sensor fixes my coolant temp going to cold and back up to normal temp issue. 

Hope you sort out the problem you was having with coolant temp.

Dean

[Nicko6786]

Hi ratt,

If I change from stock radiator to aluminum radiator....where do I put my coolant temp sensor ?

[Donthomas]

On my lexus is200 I have a rough idle only on cold start but as the engine warms up it the idle gets smooth. What can be the cause?

[steve2006]

1 hour ago, Donthomas said:

On my lexus is200 I have a rough idle only on cold start but as the engine warms up it the idle gets smooth. What can be the cause?

Do you have any fault codes? 

Difficult to diagnose without them...could be fuel related, misfiring spark plug or coil, engine ECU.