I'm sure it is a 1/8 NPT thread. I've never taken mine off. Use some teflon pipe tape on the threads to keep it from leaking. The sender that comes with the gauge needs to be grounded so don't use too much teflon tape. Once around will be OK.
Good luck

 

Busted - I forgot Mazda didn't add that ECU feature until the S5's, when they deleted the water thermo switch on the radiator.

 

I just took out the sender. When I compared the origional one with the Splitfire, the splitfire one is larger. I don't understand how the adapter works. Here is the of the the temp sender (its in the plastic bag) Is the other two bronz pieces in the pic the adapters???



Tim

 

Yea, the others are adapters. The sender itself should be 1/8 NPT. The adapters have threads inside them right? You can use the adapters by screwing the sender into the adapters.
Remember, the sender needs to be grounded. It will ground itself when you screw it into the block. But, if you other ways to hook it up such as "T" into a hose, you need to attach a wire to the sender and screw it into a good ground such a body or block.

 

I still don't understand how the adapters work. The sender in the bag itself is to big to screw into the block by the trailing rear plug. The adapters are at least twice as large, how would they fit? The adapters do have threads in them.

Tim

 

Ahh...I guess they're not 1/8 NPT then. I guess thety're metric threads. Well, you can do this:

1) tap into your water thermostat housing and thread in the sender

2) *easiest* --- get a "T" with a 1/8 NPT and use your heater hose or any hose that will fit the 2 ends of the "T" . You should be able to find it at any hardware store. A "T" is just a "T" shaped tube usually copper and has a 1/8 NPT thread on the top and 2 open ends to attach a hose.

 

I was just wondering, you inscrewed the small sender in the block with the single peg right and not the big one with the dome looking thing? The 2 senders are close to each other but the big dome looking one is for the oil pressure . I was wondering why the 1/8 NPT didn't fit?

 

Yeah, i didn;t use the big dome one. The stock sender is just a touch smaller than the splitfire one. I think the dome things were for if the stock one was bigger than the splitfire one, I have it the other way around.

I have a question though. Why would I want a "T". I don't want to attach any hose or anything. I just want a strait connector that goes from SMALL, (which screws strait into the block) to LARGE (so the splitfire can screw into the adapter that is already in the block) I don't want all of this extra stuff.

My whole problem is though that nobody makes adapters (or "T" jusnctions for that matter) that small. I have been to a few places and still looking.

Tim

 

Well the "T' was just an idea if you can't find and adapter.
You're not attaching another hose if that's what you mean. So, it's not like you're running a hose down to the sender.
To use a "T", you simply cut a heater hose or any coolant hose that you can attach the "T" to and clamp it down. It's simple.

You're not going to find an adapter that can screw into the housing and use the sender.
I was sure the thread is 1/8 NPT. There are a few options as noted above.
If you are handy with a tap, you can use a tap to fit the aftermarket sender. **BUT** be warned if you haven't used a tap before since if you screw that hole , you are *FU*KED* ! The 1/4 NPT is too large to tap into the housing. I wouldn't suggest it since you don't want to thin the housing walls.
What most people do is tap into the thermostat housing since it is aluminum and it's easy to tap.

 

Where do you do it on the thermostat housing. Do you have any pics at atll?

Why do you say that I will not be able to find an adapter that can screw into the housing and use the sender?

Tim

 

I have yet to see one adapter other than the ones that came with the gauge. See if your parts store would carry something.
You would tap below the thermostat so in case the thermostat does get stuck shut, you'll get a better reading. Let me see if someone does have a picture. If I find it I'll post it. It's 12:15 am now so I might fall asleep looking

 

In the search, try typing in "tap thermostat housing".
There's a bunch of discussions about what you want to do.

 

ty