Adding a temp sensor in the T-stat housing?

I'm running an new temp gauge. Block drain didn't work out so I tapped the hole in the upper radiator neck on the t-stat housing.

Couple of questions:

The sensor is suppose to be grounded out through the mounting surface, ie no sealant on the threads. I'm not certain the sensor is going to ground itself out?

I hooked up power on the rig and the gauge just sits there. The sensor is now grounded out through the chassis which I figured would work.



So I ran a ground from the engine to the sensor and didn't seem to do much, so hooked the ground (red clip cable) to the sensor then the gauge started to read.



So do I need to run a ground on the sensor? Anyone run one of these single wire sensors?

Second part is the gauge was off a bit from the other temp sensor when I compared the two on the laptop and the gauge. What I'm trying to figure out is did I put the gauge in a bad spot? Should I have stuck in the heater hose neck?

You didn't mention the year, but a**uming 96+; the PCM is giving you the temp gauge reading, so it may never be an "exact" match to your aftermarket gauge, even though they are mounted in near proximity to each other.

If you had mounted it in the block the reading would be different there.

The bolts that hold the housing to the head should carry ground. I moved the one-wire sender for the stock gauge to the front of the thermostat housing and it works fine there.

It's generally better to tap into the heater flow since coolant always flows there (even on the old style with the valve, the fluid still flows and is just returned via bypass valve)

Stock computer is gone, running a painless computer/system. 97ish engine. I would assume that the upper hose neck on the location of the stock temp port are close enough to read similar temperatures?



I was going for the block but as I noted in another post the block drain is 5/8-18 not the 3/8NPT.

Weasel said:

Stock computer is gone, running a painless computer/system. 97ish engine. I would assume that the upper hose neck on the location of the stock temp port are close enough to read similar temperatures?



I was going for the block but as I noted in another post the block drain is 5/8-18 not the 3/8NPT.

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http://www.autometer.com/cat_accessoriesdetail.aspx?vid=65

wrong way, thanks though.

Drain Plug is 5/8-18F, so I would need a 5/8-18F to 1/8MNPT.

I also thought you should put a temp gauge before the thermostat incase it gets stuck closed. If for some freak reason it gets stuck closed and your gauge is downstream you won't know it.

iwannadie said:

I also thought you should put a temp gauge before the thermostat incase it gets stuck closed. If for some freak reason it gets stuck closed and your gauge is downstream you won't know it.

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yes good call, I forgot that the heater hose section and stock sender location bypass the t-stat. Dang it, knew I forgot something.

Update:

Pulled the sensor out of the water neck as pictured above and plugged that hole.

Drill a new hole where everyone says to put it and it's now working. There is a slight leak as the tap slipped and I think the hole is just a bit too loose. Gauge seems to be grounded out fine now and working correctly, pretty much nuts on with the computer gauge.

This took a little longer as I had to pull the housing off, but it was pretty simple. I will probably order a hesco hi flow housing and retap it so I don't have plugs and leaking holes all over the place.