Putting the motor back together question
 

Its been 3 years since I've pulled the motor apart and its finally time to put her all back together. starting to bolt all the goods on and I noticed this random threaded hole. Is something missing? its the one up and to the right of the spark plug (no those are not the plugs im using lol)

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Coolant sensor for the stock gauge goes in there.

I have two sensors at the front of the motor...I thought one of those was the temp sensor. Or is there one for the ecu and one for the gauge?

There are two sensors on the back of the waterpump housing. The top green one is the coolant sensor for the ecu. The one below that is black and is the fan switch. If you have an automatic car it will have a third sensor on the front of the thermostat cover. The one you have missing on the rear iron is the coolant sensor for the factory gauge.

Then I think I have some things mixed up. Wise wisdom welcome

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I did have a pic when I pulled the motor apart and it shows them to be in the right place

Went out and grabbed a picture of mine.

That''s a good place for an aftermarket sensor. It''s not NPT tho

Thanks Houston! Now to hunt down that little bastard lol. An aftermarket sensor would read incorrectly on the stock gauge wouldn't it?

The stock gauge is crap. It is not linear and won't read hot till it's too late. You need an aftermarket gauge to adequately monitor engine temps

What kind of turbo are you running? Looks a bit odd ;)

It's an IHI Rx8 turbo. Rare turbo to go on a street car. Probably why it looks so odd