Outer Limits 4x4 Board

Both me and a mate of mine have recently installed mechanical water temp guages in our cars (mine's a vitara, his is a gq patrol). but the sender that came with the gauges was too big to fit into the thermostat housing.

so what we did was get a reducer to screw into the housing, then the sender screws into the reducer. the only problem with this, is that the sender sits totally outside the housing and doesn't read accurately (mine only shows just under 60* , his shows just over 60*). i assume this is cause there would be bugger all waterflow around the sender.

so, we were wondering if its possible to braze a bit of copper onto the sender unit with an oxy, that is a smaller diameter than the sender itself, so that we could extend it into the thermostat housing, so it'd read better.
i'm not sure about this method, as i reckon it'll destroy the sender unit when its heated up with the oxy. will it?????

also, how have others fitted aftermarket mechanical water temp guages to their rigs if the sender was too large to fit into the housing????????

On the side of the block towards the rear of the motor, there should be a drain plug - this will be the lowest point of the water jacket. You should be able to plumb in the sender to this point.

I'm not sure of the construction on the mech senders, I think the copper tube contains a fluid responsive to temp, the expansion of the fluid actuates the gauge. Cold solder would be better than brazing - too much heat to braze.

I've just put one of these on the camolux - the sender went into the factory sensor position (thermostat housing) and the factory sensor went into the drain plug position.

The GQ will have the drain plug on the passenger side of the block.

cheers area54, only one problem with using that back one on my mates patrol. its a turbo diesal, so that outlet is used to cool the turbo.

i've attached a pic of how our setups are currently

Is there still coolant contacting the mech sender, or is the reducer blind? I don't think there would be much loss anyway - the sender will still heat up via conduction from the housing, might be a couple of degrees out - still very reliable. The temps you quoted for both sound about right anyway. As long as it's strong and the coolant won't piss out, and the senders can't get knocked by anything in the engine bay, can't see a problem.

Area54 wrote:I'm not sure of the construction on the mech senders, I think the copper tube contains a fluid responsive to temp, the expansion of the fluid actuates the gauge.

Correct. The fluid if I remember is come form of alchohol, break the line or crack it, and throw the whole system away.
I had one for my GQ but was too short, so got an elect one now thats in a dash pod, looks sweet next to boost and EGT gauge...

bogged wrote:

Area54 wrote:I'm not sure of the construction on the mech senders, I think the copper tube contains a fluid responsive to temp, the expansion of the fluid actuates the gauge.

Correct. The fluid if I remember is come form of alchohol, break the line or crack it, and throw the whole system away.
I had one for my GQ but was too short, so got an elect one now thats in a dash pod, looks sweet next to boost and EGT gauge...

bogged, do the electric gauges have a smaller sender unit or are they the same size as the mechanical ones?

antt wrote:bogged, do the electric gauges have a smaller sender unit or are they the same size as the mechanical ones?

You buy to suit. So the sender goes right in, like water into this chalk...

its supposed to read approximately 72* apparently, so its about 15* low

Fitting the sender in the drain plug on the block will not read correct. you want the Temp as the water leaves the block not when its only part way through. This is why factory temp senders are as close as possible to the Top Radiator hose. Water enters the engine cold and exits hot.


There is another way to fit the Capilary style guages but it wont read right untill the Thermostat opens. Use a short section of Copper Pipe that is the same diameter as your top Radiator hose. You then need to Braize a fitting in to it so you can fit the sender. Cut a small section from your top hose and fit this into it. You used to be able to buy a bolt in addapter to fit in the radiator hose which only required a 3/4 hole cut in the hose but i have not seen one of these for a few years.

we thought about doing it that way ruff. have you seen it before? does the temp jump around as the thermostat opens and closes? or is it pretty reliable and constant?

Its fairly constant once the Thermostat opens for the first time.

cheers ruff, might give it a go. has to be better than the current spot

Ive also done it Dodgy and just placed the Sender inside the top hose and just used silicon around the capilary line and done the hose back up.

RUFF wrote:Ive also done it Dodgy and just placed the Sender inside the top hose and just used silicon around the capilary line and done the hose back up.

hmmm, thats probably a good way just to check and see how it work

ah, just remembered i have the radiator hose that i blew the other week still around somewhere. might just dodgy it up in there to give it a go

Dont cut a hole in the hose if you are going to try my last suggestion. You run the Capilary line through the end of the hose and under the Hose clamp.

righto, i was just gonna stick it through the hole cause the old one already had one in it , but i'll try your way ruff