Correct location for placing water temperature sensor?

[no_8wire]

What is the correct location to put an axillary temperature sensor?
I have the adapter to connect it in to the radiator hose, but am at a loss as to which one (top or bottom etc) Obviously there will be a big difference in the reading if I get it in the wrong place (after cooling/prior to radiator)

Application is a Hilux Surf.

Cheers

[sergei]

Correct place will be to tap it right before thermostat, in the thermostat housing.

[fivebob]

Correct place will be to tap it right before thermostat, in the thermostat housing.

Why? That's the coldest part of the system, you want it at the hottest part

Best place is in the top hose just after it exits from the engine.

[Akane]

Water junction, right where it exits the head, usually behind number 4 cylinder and around the distributor (4E-F, 3S-G etc...)

If you tap it right before the thermostat like sergei said, you'll be seeing if the radiator is doing it's job, not if the engine's gonna blow up into about 124857 pieces.

[sergei]

Correct place will be to tap it right before thermostat, in the thermostat housing.

Why? That's the coldest part of the system, you want it at the hottest part

Best place is in the top hose just after it exits from the engine.

You are thinking of 3S I was thinking of 4A . For example on 4AGE the thermostat is located on the the side of the head (gearbox side) where the water exit is. This is the hottest part on 4AGE.

On 3SGTE thermostat located on the waterpump housing, while the sensors are on the elbow.

You are right clarifying that it needs to be on exit.
So he needs to determine which way coolant flows and put it on the exit.

[sergei]

Water junction, right where it exits the head, usually behind number 4 cylinder and around the distributor (4E-F, 3S-G etc...)

If you tap it right before the thermostat like sergei said, you'll be seeing if the radiator is doing it's job, not if the engine's gonna blow up into about 124857 pieces.

Again it applies to 3S.

Best way is to find out what engine OP is using.

[rollaholic]

dont think you'll find either of those engines in too many hiluxes tho

[no_8wire]

Nope has a 2L-T hence why I want to keep a close eye on the water temperature

fivebob, the top hose from the radiator is connected to the thermostat housing (and from that back to the head is all alloy)

Engine similar to pic (except this is NA 2L)
See hose of thermostat leads to top of radiator, with the lower radiator hose to the left underneath it (next to air filter)

[fivebob]

Put it in the top radiator hose, that's usually the hottest part.

Hot water flows into the top of the radiator and cold water flows out the bottom, I can't think of any example that is the other way around. If it was then it would be as efficient as hot water rises and clod water sinks.

If the thermostat is attached to the top radiator hose then the flow is out of the thermostat, if it's attached to the bottom hose it flow into the thermostat.

[sergei]

Put it in the top radiator hose, that's usually the hottest part.

Hot water flows into the top of the radiator and cold water flows out the bottom, I can't think of any example that is the other way around. If it was then it would be as efficient as hot water rises and clod water sinks.

If the thermostat is attached to the top radiator hose then the flow is out of the thermostat, if it's attached to the bottom hose it flow into the thermostat.

I would put it "under" the thermostat as the temperature reading will be affected if thermostat is closed or open (It would show cold until thermostat opens, then it would jump up until thermostat closes, then slowly drop... and so on).

[ee904age]

I would put it "under" the thermostat as the temperature reading will be affected if thermostat is closed or open (It would show cold until thermostat opens, then it would jump up until thermostat closes, then slowly drop... and so on).

And with it in the top hose, if the thermostat doesnt open at all for some reason, you'll be none the wiser until your engine dies.

[sergei]

BTW on the pic it looks like there is standard sensor sticking out already in the right area - that little brass stub.

[no_8wire]

Sweet will put it in the top hose.
Not to worried about the open/closure of the thermostat as I am still running the standard water temperature sensor as well (i.e I have two WT gauges 1 stock 1 aux) So will be able to read off the stock gauge until the thermostat opens and then read off the aux gauge


Its more for when I am towing/ offroad so I can keep an eye on the temperate as the stock one is supposedly not the best.

Plus I have a inline adapter already so will just use that rather than tapping the housing (and existing is to big for new sensor)

Cheers i have the answer I need.