Coolant bung on back of engine

Roadrunner · Postby **Roadrunner** » Wed Sep 16, 2015 11:03 pm

So digging around for a spot to mount a coolant temp sensor on my SE I came across this threaded bung. It's underneith the factory coolant sensor on the back of the engine and looks sort of accessible.
Iv done some researching but came up mostly empty. Does anyone know if this is a usable spot for a sensor? Is it even in the coolant flow? (Kinda looks oily??)
And most importantly, what thread pitch would it be?

tbro · Postby **tbro** » Thu Sep 17, 2015 11:51 am

Yep, that's a factory coolant sensor point, from memory 10 x 1 thread, certainly metric, std Mazda sender.

TrackAttack · Postby **TrackAttack** » Thu Sep 17, 2015 12:28 pm

It should be 1/8th BSP

tbro · Postby **tbro** » Thu Sep 17, 2015 1:11 pm

^^^^^^^^^^^^^^^^^^^^^
Correct, and the sender is from a 1.6 or 1.8 NA motor

Sender from an NB is metric, it's 12mm x 1.5 ( so I stuffed up that as well) :roll:

Nevyn72 · Postby **Nevyn72** » Thu Sep 17, 2015 1:44 pm

TrackAttack wrote:It should be 1/8th BSP

Is that 1/8th BSP or 1/8th BPT28?

Roadrunner, I believe you are planning on using a speedhut gauge and it's associated sender correct?
If so then these units use a 1/8th NPT27 thread on the sender so you would need to re-tap the hole (good luck getting a tap in there! :shock:

)

I remember looking into using this port for my own speedhut gauge but from what I read about them, unless you fitted the sender while the head is removed (or at very least the engine is out of the car) it was just too much trouble to make it work. I ended up forking out a (large) sum of money for the Maruha sandwich plate that fits where the thermostat is located on the front of the engine.

Roadrunner · Postby **Roadrunner** » Thu Sep 17, 2015 2:01 pm

Yes looking to use a speedhut temp sensor which uses a 1/8inch NPT thread.
I am replacing the factory cluster gauge with this so I need it to read temps before the thermostat and at the hottest part of the engine, so near the factory sensor is ideal.

Access doesn't look too bad really, but I don't want this to leak due to wrong thread size. Want to get it right the first time.

Speedhut sell adapters which might actually make the install easier, but is that wise for coolant temp sensors? (Going to let Mania install the sensor :twisted:

)

project.r.racing · Postby **project.r.racing** » Thu Sep 17, 2015 2:29 pm

viewtopic.php?f=29&t=69481

see pics a couple of posts down. common location for temp sensors.

Roadrunner · Postby **Roadrunner** » Thu Sep 17, 2015 2:33 pm

Sorry, a little confused. So the thread where the small black bung is, is a 12mmx1.5?

So I would require this adaptor to fit the speedhut sensor in? http://www.speedhut.com/ecommerce/produ ... s-Steel%29

Nevyn72 · Postby **Nevyn72** » Thu Sep 17, 2015 2:34 pm

Roadrunner wrote:Access doesn't look too bad really, but I don't want this to leak due to wrong thread size. Want to get it right the first time.

*Ducks downstairs to the garage to look under the bonnet*

Really? :shock:

From what I can see you would need to remove quite a bit of hardware and get a good extension piece for the tap..... Even then there's not much room for the handle to spin around....
At least you would be re-tapping a similar sized hole so getting it started and keeping it straight shouldn't be a problem.

Roadrunner wrote:Speedhut sell adapters which might actually make the install easier, but is that wise for coolant temp sensors? (Going to let Mania install the sensor )

Couldn't see an appropriate sized adapter but using something like that would likely remove the sender probe from the coolant flow proper. Your temp readings would be affected by the surrounding environment, including the proximity to the EGR pipe.

If you're going to get Mania to do the install they should be able to give you any advice you need as to how feasible it is. :wink:

I've actually got a 1/8 NPT27 tap if you wanted to have a go yourself.....

Nevyn72 · Postby **Nevyn72** » Thu Sep 17, 2015 2:41 pm

Roadrunner wrote:Sorry, a little confused. So the thread where the small black bung is, is a 12mmx1.5?

So I would require this adaptor to fit the speedhut sensor in? http://www.speedhut.com/ecommerce/produ ... s-Steel%29

I think you'll find the black bung (un-used old sender port) will be 1/8 BPT28 and is a head casting relic from earlier generation BP engines.
The new sender location in the bolt-on casting beside the old port will have the metric 12mmx1.5 thread.

tbro · Postby **tbro** » Thu Sep 17, 2015 2:43 pm

BECK/ARNLEY 2011220 {#2011627} SWITCH; Thread Size: 27 NPT Info One of our most popular parts
Flag indicates this part fits vehicles sold in the US Market. It does not indicate where the part was made -- manufacturers produce parts in multiple factories worldwide. Flag indicates this part fits vehicles sold in the Canadian Market. It does not indicate where the part was made -- manufacturers produce parts in multiple factories worldwide. w/Gauge

Straight off Rockauto site, if the sensor that you want to use all good, if not HAVE FUN.......

Sorry, a little confused. So the thread where the small black bung is, is a 12mmx1.5?
The thread in the head is 27 NPT..................that's the small blanked off plug in the photo

Nevyn72 · Postby **Nevyn72** » Thu Sep 17, 2015 2:50 pm

tbro wrote:BECK/ARNLEY 2011220 {#2011627} SWITCH; Thread Size: 27 NPT Info One of our most popular parts

Is that the sender designed to fit the port where this bung is located?
ie. the one used in pre-96 BP engines?

If so then it has the same thread & pitch as the speedhut sender unit and should bolt straight in! :mrgreen:

Roadrunner · Postby **Roadrunner** » Thu Sep 17, 2015 3:08 pm

If its 1/8th NPT (I assume 27NPT is the same thing? These thread differences does my head in) then that would be awesome.

I'v shot an email off to Mania to see if they can confirm the thread. Fingers crossed it is the same as the speedhut sensor thread!!

hks_kansei · Postby **hks_kansei** » Thu Sep 17, 2015 6:07 pm

If the bung is accessable why not just remove it and take it to enzed or wherever you'll be buying your fittings.

Just ask for one the same as that (and bring the gauge sender so you can also ask for an adapter if needed)

Roadrunner · Postby **Roadrunner** » Thu Sep 17, 2015 8:45 pm

Quite time poor at the moment otherwise I would.
Also don't have the opportunity to get too a shop during work hours.

I had an idea though, just went to the tridon website and searched for the coolant gauge sender for 1.8L NA BP engine.
Result said the thread is 1/8 GAS
searched what a GAS thread is: BSP! :evil:

That sucks :frown:

If it was the right thread it would have been easy to get the sensor in there. I highly doubt there's enough room to tap it though. I'll see how keen Mania are at doing it, otherwise back to the drawing board.

Thanks everyone for the help and advice :beer: