I'm going to installan electric water temp gauge and I want to put the sensor in the engine block so I was thinking getting a drain plug out drilling it out then tap it or weld the sensor bong in to it to put the sensor in it. I know you are thinking that I should go look and find one but the car is no around me. I'm in Puerto Rico right now for 2 weeks.

 

Why not just drill a hole on the thermostat housing?

 

There is a block drain plug on the spark plug side of the engine, near the bottom.

 

I think it be more accurate reading if I put it directly in the block in case of a water pump failure

 

Here's a photo of where it is...

I have quite the experience with this little plug...I your temp sensor is standard size it's going to be pretty hard to drill out the plug...the plug head is about the size of a dime, maybe a tad bit smaller. Really doubt it can be drilled and tapped for a sensor. Probably the best place is the thermostat housing.

I have two temp readings...one from my PFC and one from my AST...(lots of people disagree with the AST location by the way) The two readings are usually 2-3°F off....the AST being cooler. I have the sensor tapped into the AST about 2" down from the cap and doesn't start recording temp till the thermostat opens...great way to know you have the go ahead to punch it....It tells pretty accurate temp but the thing I like about it the most is it's a pretty damn great way to know if you are loosing coolant...at that position if the coolant drops below the sensor in the AST then the temp on the gauge drops to around 70°f...this is a clear indication that your coolant has gone somewhere and gives you a prewarning before the dreaded BEEEEEEEEP of the coolant level sensor....the PFC will still keep the right temp...just thought I would share my setup..

good luck!

 

Even with the temp sender in the thermostat housing, it still only starts reading the engine temp after the thermostat opens. I didn't realize this before I did the mod, and find it weird that so many people recommend this location. I guess it's convenient, but I like to see my engine temp while it's warming up.

 

Ok, so where did you put yours?

 

Well that makes sense...I was always wondering why it took my WT gauge almost 10 minutes to move off the peg

 

Well I like that idea, but can it tell you if you have problems with the water pump?

 

I put mine in the thermostat housing

I didn't realize it did this until I already finished the drill/tap and install.

 

I dunno, I not well versed in waterpump...maybe one of our veteran members can chime in on that.

 

Mine is tapped into the thermostat housing and I still get readings before the t-stat opens. It slowly raises until 180 F or so and then tries to stabilize to that temp. It's obvious when the t-stat closes because usually the temp quickly drops to 170 F or so.

Just tap the t-stat housing. It's easier and it gives good results. Honestly, I think people are a little too paranoid with their temps anyway....

 

rynberg: I don't understand how you are getting readings before the t-stat opens. I put my sender in the location recommended on the robinette site. My readings might go up to around 110 to 120F, then then when the t-stat opens it jumps up to 180F.

Actually, I was able to detect when my t-stat failed because all of a sudden I started getting readings during the entire warmup period. When I removed the t-stat I found that the rubber gasket that seals it was nearly destroyed.

 

Sorry to bring this up from the dead, but wouldn't installing a brass adaptor with the same pitch as the drain plug and placing the temp sender in it, be sufficient for an accurate "block" water temp reading?
I currently have my defi gauge hooked up to the factory port located on the passenger side of the water housing. I'm not all that happy with the temp readings since it's after the t-stat, Which is why I'm looking for a better spot. Also I'm all about using pre-drilled locations :-)
Has anyone used this location? If so what are your readings?

 

That would be a bad place to spring a leak

 

Here is a good thread on sender locations and the install process.

https://www.rx7club.com/3rd-gen-archives-73/water-temperature-sensor-how-tap-install-247152/

 

Better thread here:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/water-temp-sender-thermostat-housing-bad-idea-392910/

Both are in the FAQ. Just added the second thread.

 

+1^

 

I was the last one to post on that thread but with no response. No big deal though, I just went with what I posted and it's worked but like I said and everyone has said it only shows temps after the T-stat.

"That would be a bad place to spring a leak " I agree totally, but any place that springs a leak is a bad place ;-)

I just wasn't to sure if anyone else has tried that spot. My old FD had a bad gauge when I bought it and so I just went ahead and used the stock sender location for my after market gauge. But since this FD has a working gauge, I'd like to keep the look of a factory working one while relying on my DEFI gauge for true readings.

 

I want a sensor bong...

 

Must be a puerto rico thing....... :-)