Ok guys, it's been almost 2 months now and I still haven't figured out where to place my new temp sending unit without drilling to any parts of the engine nor the water pump housing.

I just noticed that there are two outlet at the back of the water pump housing, one is for the water thermo sensor and the other is for coolant bypass hose. Can I use one of these two? Or maybe just drill a hole in the coolant filler neck?

 

no easy solution to this. best to remove the water pump housing and drill and tap hole for sender. sorry

 

ok before i go drilling (though i hate it) i wanted to know first, what is the difference between the temp sending unit under the oil filter and the water thermo sensor? Because I still think that I can just insert a tee in their and use that for the aftermarket temp sending unit and the water thermo sensor.

 

The temperature sending unit(under oil filter)is just to provide the signal for the temperature gauge on the instrument panel.It is not connected to the ecu in any way,has no impact on the management of the motor.
The water thermosensor provides the engine temperature info for the ecu,and the signal can vary the quantity of fuel supplied by about 20%.That's why your engine runs crappy when it acts up.
I would attempt to put your aftermarket temp sender at the location of the factory temp sending unit.

 

As an emergency procedure a couple of years ago, I installed one in the filler housing. My car did not have a electric fan so there was no temp sw on the filler housing. Just a boss. I drilled in the boss and due to cheapness and laziness, used JBWELD to hold it in place. The hole was virtually the same size as the water temp fitting so it was almost a press fit using JBWELD. The sensor is still there to this day but the sensor *tube* broke off long time ago.Just had to know what the REAL TEMPERATURE was. Not that toy gauge reading on the dash from Mazda.

 

If you're using an aftermarket gauge why not remove the stock sender under the oil filter and buy and adapter to use that hole? The stock sender thread is an 1/8"BSP.

Chris

 

ok guys, i actually went to a junkyard this morning to rip a water pump housing from one of the RX7 there because I didn't want to experiment on my own car, duh! Anyway, I checked the whole thing inside and out and found out that you can actually tee into the water thermo sensor. I might just do this or drill a hole accross it, which is the front side of the water pump housing.

If it were only available, I would have done it long time ago.

 

I bought two of them at a local place in town. It was a PITA finding anyone that had it. Most guys just look at you like you're stupid when you say "British Standard Pipe". If you'd like I can pick one up for you and put it in the mail. The ones I had are actually three fittings pieced together so the cost is about $20 for the whole system. If you want one just let me know what size thread you have on your sender.

Chris

 

Hey Chris thanks for the offer. I didn't know anything about this BSP. Anyway, my temp sender is 1/8" NPT (I guess NPT and BSP are different). So why did you use 3 fittings altogether? Can I just get one so it'll be cheaper?

I will email you my mailing address. Thanks again.

 

The place I went had a BSP to -3AN adapter. It's about an inch long. Then the next piece is a -3 to 3/8 NPT adapter. It's about 2 inches long. The last piece is a 3/8 (or 1/4, I forget) to 1/8 NPT adapter that I bought at the time but another one came with my gauge when I bought it. The expense is in the AN fittings. The place I went is a large hydraulics supply house and they didn't have a one piece adapter. You might want to try SMC for a one piece deal. You'll need a 1/8 BSP to 1/8 NPT adapter. SMC's email address is smcprod@gte.net Steve is VERY knowledable, and if he can't find it no one can. I got in a hurry and wanted the adapter locally, like now, and never tried him.

Just drop me an email if you want a copy of what I use. It's actually kinda nice to have the longer adapter. It gets the sender out where you can access it easily.

Chris

 

Dude, I got ya covered. Wish I would of found this earlier. Autometer makes a 1/8 BSP x 1/8 NPT adapter. It is Autometer #2269. Go to Summit Racing at www.summitracing.com and enter ATM-2269 in the part number search window. You can order online. The part is $9.95 + handling ($6.95).

Chris

 

Hey, I have a '90 GX and I screwed the 1/8" adapter that came with my Autometer Gauge right into the stock hole (Under the Oil Filter) with no problems. Maybe it was different on 86' - 88's... I doubt it though. Pull your stock sender out and line up the treads with the sender you got with your aftermarket gauge and if the treads match, your laughin'

Good luck, I know I racked my brain for a month until I tried the obvious...

-Mike

PS. If the "free" method doesn't work. Ludwig is right, Autometer sells adapters too...

 

I guess it is different because mine doesn't work.

Hey Chris, I've ordered this before and it only works for oil pressure gauge because the adapter's female side is too short for the autometer's temp sending unit. But now another question come into my mind. If the #2269 is 1/8" BSP, how come the original temp sending unit is smaller than this adapter. So this means that the thread in the engine is not 1/8" but smaller. Do you guys know exactly what the size of the thread in the engine is for 88 N/A? I am ready to drill a hole in my water pump housing so if I don't find an answer, I'll probably just go ahead and do it.

 

 

I've got a 90 motor in the car and an 86 and 89 on the floor of the shop. All have the same thread. I took a stock sender to my source and they said it's 1/8 BSP. At any rate, the piece I told you about earlier does work. If that's what you want I can still get it. Sorry to cause an uproar about the Autometer adapter.

Chris

 

So are we saying that my sender from autometer shouldn't have fit?? It didn't even give me much resistance with a small amount of teflon tape on it. And it definately doesn't leak. What's up with that?
-Mike

 

The sender from Autometer is probably an 1/8 NPT. The thread in the side housing is an 1/8 BSP. Both threads are an English or SAE thread. They have the same thread pitch and are the same basic diameter. The difference is that NPT uses a flare that the BSP doesn't. The NPT starts at the same diameter as the BSP and then flares out and gets bigger as you thread it in. I guess if you got enough threads in to keep it solidy mounted it should work OK.

Chris

 

Hey Chris, I don't think that the original sending unit has the same diameter with the autometer one. Because the bulb from autometer wouldn't even go in. Unless porcupine got a different sending unit.

About the adapter that you found for me, thank you so much for that dude. But I'm just gonna tap onto the water pump housing. Because I really wanted to keep the stock gauage working plus the new one. Unless there is a tee fitting that goes with the adapter that you are talking about, I'll get it. Thanks!