1JZ engine temps vs 18RC engine temps

[LeeRoy]

Do you think i should get a 18RC sender still? Or this should be okay..?

Match the sender with the guage.

You are using an 18rc/ta23 guage so use the 18rc sender. As stated above it will have the guage sitting where the 18rc used to sit since they operate in near the same temp.

Stop messing around with other sensors as although the engines have the same op temps, the sender and guage calibration can be way different to that of the 18rc/ta23 and will therefore not work.

Your 18rc sender is the solution here.

[Smokey228]

You must spread some Reputation around before giving it to LeeRoy again.


Cheers,
Jase

[Smokey228]

I went out and got an 18r temp sender the other day. Had to go to spare parts shop, its a VDO brand, and apparently toyota dont do them anymore...
Put it in and let the car run for a while... I have a thermo in their now, but no switch, so it runs constantly...
So it was cool for a while, but the gauge crept up, to about halfway, i started to freak as the thermostat still hadn't open and the gauge was creaping past half way...

I started to wonder why the thermostat would have stopped working since last week... So i put the old 7M temp sender in, and it read about halfway between 0 and 1/3rd marker.
From memory, the thermostat would open at about 1/3 marker with the 7M sender.

So it would seem the the 18r sender, is going to start working with the 1jz at about 2/3...

I am going to get a thermo switch tomorrow and fit it with a 2nd fan, set it to 80degrees...
I figure, if the thermostat is supposed to open at 82degrees. Then when the fan turns on, i will know where the engine is supposed to operate, and i can tell where the gauge is supposed to read...
If its 2/3, than the 18r sender will read to high...
I'll try the 7M one, if it sits at 1/3 when the fans turn on, i'll go back to that, as i feel a wee bit more comfy having the temp gauge read 1/3 instead of a line away from 'cooked'...

I need to eventually get a proper temp gauge, like a autometer or something, so i can see correct numbers

Cheers,
Jase

[Smokey228]

Oh, so my qeustion is,

If the 1JZ is supposed to operate at 82degrees, and the 18r at 79 degrees, shouldn't the gauges read similar positions? *This is assuming the 1JZ and 7M senders are same*

Cheers,
Jase

[LeeRoy]

The guages wont necessarily read in the same position because you are talking about using different senders which will more than likely have different resistances and due to this give different readings.

Heres something you should probably do.

Pull the temp sender out and place it into some boiling water with a thermometer in the water also. Then see where it reads on your guage relative to temperature. Do this for both senders and see how close they are. It might even be an idea to mark or write on your guage the temps, ie 80deg=half way, 100deg=red mark.

Also, thermofans come on after thermostat opens.

Ninja Edit: You could also test their resistances to determine how similar they are that way although the thermometer way is probably more beneficial to you knowing exact temps.

[Smokey228]

Thats not a bad idea. But a lot of effort, im going to buy one of those dodgy 20$ temp gauges and watch the water temp...

Though, im confident that the 18r temp sender isnt going to be sufficient. I got a davies craig temp switch, and at 40degrees the gauge read 1/8th. At roughly 70degrees it read a little bit above 3/4... At what i think would have been about 80-90degrees, it was almost in the read...
When the thermostat opened, it was sitting slightly out of the red zone...

Im going to do the same tests with the 7M sender. At a guess, i will need to run a 1JZ Sender, am hoping 1jz and 7M senders are the same...
But obviously, none of these numbers will be reliable until i have a temp gauge next to them... And a 20$ temp gauge will be pretty average. I will try and borrow my mates autometer one aswel (

Cheers,
Jase