Temperature Gauge Installation

Last updated: January 5, 2000

Date: Tue, 27 Jan 98 13:15:49 -0500
From: "Linthicum, Sandy" (linthias@sandy-ntws.usps.gov)

>I'm planning to add an AutoMeter mechanical water temp
>gauge when I have the rest of my cooling system apart soon.

>Also, the tubing is 6 ft long, which seems like it could
>be tight for mounting on the steering column. Has anyone
>had any problem with that length or is it better to go with
>the longer version?

6 ft is to short - you can probably stetch it to fit but it will be in the way and a pain in the a!! forever.. Return it and get the 12ft one.

>From previous posts its seems most people are taping a
>hole on the flat portion of the thermostat housing.
>Autometer makes a 3/8" NPT adapter which I will use.
>Any tips when locating and making this hole?

There is only one logical place for the hole. NPT is a tapered hold, tapped in aluminum alloy. Tapping Aluminum is tricky, so get the correct specialized/trick tapping lube for aluminum and take your time or have someone else do it for you. I would suggest covering the metal capulary tube from the sensor to meter with something (like rubber hose) to protect it from heat & abrasion.

If mounted like I did mine, the new guage will remain at 0(lowest) till the thermostat open and lets hot water start to circulate. Temps will also go way up when you shut off the engine and part (heat soak). Both normal.

Pay close attention if temps go over 230F, they then to exponentally go up very fast from here and you want to keep them under 240F at all costs.

In cruising traffic, just turning on the A/C starts the fan running on low and will drop temps on a hot day from the 225-230F mark to less than 200F in a few minutes.

______________

Date: Thu, 11 Jun 98 07:10:42 -0500
From: "Linthicum, Sandy" (linthias@sandy-ntws.usps.gov)

You should be able to use a 3/8 NPT fitting with the sensor if I remember right. You really do not want to drill/tap a hole in that housing as big as the 3/4 NPT fitting/adapter that comes with the Autometer guage. You should also have the 10 or 12 ft. kit, not the 6 foot. 6' is not enought to route the tubing properly.

I concur on having a machine shop, etc. do the drill and tap. NPT is a tapered hole and tapping in aluminum is tricky anyway.

______________

Date: Tue, 5 Jan 1999 00:47:08 -0800
From: Stephen Stanley (sstanley@microsoft.com)

Most temp senders seem to be UNF or NPT which I think are imperial threads, so some form of adapter is required. You can buy M16 x1.5 (I think this is the right size for the hole, others have used 3/8 NPT to imperial size adapters see http://www.scuderiaciriani.com/rx7/temp_gauge_install.html) but as you say, this will make the sender sit too high in the hole and will clash with the filler cap. It is worth trying one of these as a first step, as they only cost 5-10 dollars and cutting the adapter down, The adapters usually come with a hex end on them so you can screw them into the hole, but you should be able to cut this off since the hole is bottomed off, it will stop when it hits the end, so you don't need the hex end to stop it going down the hole. Doing this may mean that you clear the filler cap - but this depends on your temp sender.

Note that you will only read water temps when the thermostat is open since the housing is the wrong side of the 'stat. The pipes to the throttle body run water all the time, but seem to run 10-15 degrees cooler by all reports. You take you own choice....

______________

Date: Thu, 07 May 1998 21:11:33 -0700
From: Smeagol (gollum@netcom.com)

Thanks to all who replied on my Intellitronix water temp gauge questions. My problem did turn out to be the ground I was using. If you plan on installing this gauge, don't use a ground for the lights unless you want it to act really funny. I moved the ground to metal/frame and it behaved normally. I was also playing around with the dimmer wire on the Intellitronix and found out that the gauge only dims half way. They also confirmed this over the phone. You can set it up to either dim w/the dimmer switch slowly, or just click down to half dim when you turn on the lights. I opted for the second way since I rarely use my dimmer switch.

Date: Tue, 23 Jun 1998 12:13:00 -0500
From: "Westbrook, Chuck" (CWestbrook@tmh.tmc.edu)

Since I'm running the air pump, my sending unit could not fit in the tapped outlet on that side of the thermostat housing. That leaves only two options:
(1) place the unit in the coolant line that runs out of the top of the throttle body, or
(2) drill and tap into the thermostat housing.

I initially went with (1) and last week end changed over to (2). Option 1 is easier but also gives a lower temperature reading of about 10-15 degrees because the coolant is cooler there. It also gets in the way a little when doing a TPS adjustment.

For both sets of following instructions, it would be better if the engine is cold.

OPTION 1:

  1. I started with a 3/8" pipe thread brass "T". Into each of the two opposite ends screw in a 3/8" pipe to 3/8" ID hose adapter. Into the top of the "T"; screw in the adapter to hold the sending unit, or the sending unit.
  2. Remove the coolant hose from the top of the throttle body and put it on one end of the "T".
  3. Then using a 3" length of 3/8" ID hose, connected the other end to the throttle body.
  4. If the sending unit is electrical, use a screw clamp to attach a grounding wire to the "T" and run the other end to one of the grounding points on the firewall, then attach the sending wire.
  5. Use Teflon tape on the fittings when screwing them in.

OPTION 2:

  1. Remove the IC and air filter assembly.
  2. Remove the filler cap from the thermostat housing and run a small hose as far down the hole into the large coolant hose as possible. Drain out the coolant with this hose and save it. I got about 3/4 of a gallon.
  3. Remove the coolant hose from the bottom of the thermostat housing and put it out of the way. Place the cap back on.
  4. You will have had to previously obtained the correct drill and tap needed for your sending unit. To the right and back on the thermostat housing from the low coolant sending unit is a flat spot about 3/4" wide that is located directly in front of the thermostat and faces straight forward. The metal here is about 3/8" thick. Under all of this place a large cloth covering as much as possible. This is to catch the aluminum bits and to help make cleaning up easier.
  5. Slowly drill into the center of this flat spot until all the way through. Be careful as to not ram the bit all the way in once you are through. There is a lot of clearance between the wall and the thermostat, but don't chance messing it up.
  6. Next lubricate the hole and tap with light oil and slowly tap the hole. It helps to tap a little, back it out all the way; then repeat the process. Periodically test inserting the sending unit into the hole. When tapped all the way through with the sending unit fitting good, this part is complete.
  7. Remove the catch cloth an clean up as much of the aluminum chips as possible.
  8. Next if the car is in the garage, place some type of pan right under the thermostat housing where the hose was removed. Using some source of water (I used the garden house and adjustable nozzle) , flush out the lower part of the thermostat housing where you drilled & tapped by inserting the water into the new hole and it will flow out the bottom where the large hose was removed. It only took me about 1 gallon to wash out all debris.
  9. Using Teflon tape, screw in the sending unit.
  10. Finish up and put everything back together again.

Date: Mon, 06 Jul 1998 09:25:21 -0500
From: tom (jelkil@interaccess.com)

OPTION 2:

Can be simplified by leaving the airbox in place. Remove plastic boost pipe from turbos and rubber hose that goes from IC to throttle body. Remove the 3/8 in hose below the thermostat housing cap. Get a 1/2 qt jar and put the hose in the jar, filling it as you lower the jar. This should drain the thermostat housing, and leave enough room for a bottle of water wetter. loosen the alt belt and remove the thermostat housing (there is no sealant, it comes right off). Autometer makes a 1/4" npt adapter for their mech water temp guage. Drill a 7/16 hole in the front of the housing and tap for 1/8 NPT, starting the tap in the drill press (hand rotation of the drill press quill) and finishing it up with a tap wrench. reassemble and install sender and top up and purge cooling system.

________________

Date: Tue, 04 Nov 1997 20:42:46 -0500
From: Grant Moyer

I drilled and tapped into one of the almost round flat areas in the front of the thermostat housing. There's two of them and the bottom most one is the one I used. You need to drill a 37/64" for the 1/8 NPT tap, which I did, but I think a 9/16" is ok. Plus, if you didn't get an adapter you need a... mechanical water ... oh, I forget. It's something like a 5/8"-16 female to 1/8 NPT male. Any local automotive shop should have it, just tell them what it's for installing.

Date: Mon, 29 Mar 1999 11:12:08 -0800
From: "Kinports, Robert" (RBK1@pge.com)

I installed my new intellitronix Temp gauge this weekend, well sort-of. My plan was to install the sending unit in the hole by the radiator cap using a 3/8" x 1/8"npt bushing as others have done. The only problem with installing the sending unit here is that the sending unit is too tall & will short out against the radiator cap &/or prevent the stock winged cap from being used.

In order to provide enough clearance between the post on the sending unit & the radiator cap I had the 3/8"x1/8"npt bushing counter-bored at the top to allow the temp sender to thread all the way into the bushing. I chose this route instead of trying to further tap the sender as there was less risk of screwing up the sender. I also cut ~3/16" off the top of the sending unit electrical post.

At this point I removed the hex socket plug from the housing & began to screw in the temp sender & bushing, which was wrapped with Teflon tape. As the bushing went in it began to get progressively tougher to tighten which is to be expected with an NPT bushing due to the tapered threads. At this point the sender still wouldn't clear the cap so I decided to tighten the bushing another couple of turns. That is when I heard/felt a pop & the bushing began to thread in a little easier. It didn't take long b-4 I noticed the hairline crack I just caused in the casting.

Fortunately a new housing is only $44 from Mazda Comp plus a few clams for the 2 o-rings. BTW, this casting was superceded, but both the old & new are still available. Does anyone know what the differences are?

My suggestion to all those wishing to install the intellitronix temp sender is to NOT use a 3/8"npt x 1/8"npt bushing in the existing hole. I would suggest removing the housing & spending the $10 for a machine shop to drill/tap the housing on the side opposite the air pump. I plan to have the new housing tapped on the side for 1/8"npt by a machine shop for a cost of $10.

To those who got this to work without cracking the housing - congrats, but I don't recommend it. I suspect that you need to replace the stock winged radiator cap with the round one from the AST to get this to work.

Since I have to drain the coolant to replace the housing I decided to order the upgraded Mazda Comp radiator & replace all the coolant hoses with Goodrich at the same time. It's funny how a simple cheap upgrade can easily get turned into a more complex costly one!

________________

Date: Mon, 20 Apr 1998 08:38:45 -0700
From: Spencer Hutchings

The digital temp gauge I got is the one from Intelitronix. It is a 2" black face gauge with three red led's. It has a lead for hookup to the factory dimmer switch. Installation was as follows:

  1. Tap the supplied brass sensor all the way to the base with a 1/8 pipe tap.

  2. Pull the hex head plug from the TOP of the water filler neck. This plug is 3/8 NPT or darn close to it.

  3. Go to OSH and get a 1/8 to 3/8 sleeve.

  4. Cut sleeve to about 1/4" thickness and thread in the sensor.

> Got a couple of questions for you. Why did you decide to tap the sensor
> from the top rather than the fitting half way down on the filler neck?

I used the top because I still have my smog pump, it would not fit on the side.

> Also have you since found out what the exact size the plugs in the
> housing are?

The sizes I originally stated are correct. The filler neck seems to have 3/8 NPT plugs.

_________________

Date: Mon, 29 Mar 1999 12:11:35 -0800
From: Spencer Hutchings

> In order to provide enough clearance between the post on the sending unit &
> the radiator cap I had the 3/8"x1/8"npt bushing counter-bored

Mistake #1

> I also cut ~3/16" off the top of the sending unit electrical post.

You did not need to do this.

Take the 3/8" x 1/8" bushing, cut off the top so there is only about 1/2" of threads left and no place left to put a wrench.

Take the sender, thread it as far as you can with a 1/8 NTP die

Wrap both with teflon tape

Thread the sender into the bushing, you won't be able to get it tight.

Remove the hex bolt next to the radiator cap.

Thread the bushing/sender into the hole and tighten using the appropriate wrench on the sender.

_______________

Date: Wed, 02 Sep 1998 15:11:37 -0700
From: Lou Young

This past weekend I started installing an Intellitronix water temp gauge and ran into some problems mounting the sensor. I hit Steve's site expecting to find a whole bunch of different options for mounting the sensor, but I've only found one. So I tried it. It didn't work. More on that later. It involved using the plug on top of the filler neck, but I remember a bunch of people mounting the sensor in other locations, one being the 'flat spot' on the filler neck. I can't find the messages referring to this. Could someone point me to some good information for mounting the sensor on the filler neck?

The guy who used the plug mentioned chopping some material off the bushing to make it shorter and using a die to thread the sender further to make the whole assembly even shorter. I believe this is an effort to make sure that you can still take the cap off the filler neck. I did both. But my bushing didn't seem to want to screw all the way into the plug whole, and even with the modified sender threads, the sender was still way too tall to not get in the way to the filler neck cap. If only they had put the plug hole an eight of an inch further away from the spout. Here's some other things that the guy didn't mention: 1) Remove the spout from the filler neck. There's no gasket to replace, just an o-ring. You can't screw the bushing in with the spout still attached. 2) Don't, under and circumstances, accidentally drop the sender down through the plug hole. You'll freak out, and then have to find a way to get it out.

On a side note, since I have everything install except for the sender, I rigged it up to measure under hood temps. It's located just behind my aftermarket airbox in the engine compartment. I'm seeing anywhere from 160 degrees to 215 degree underhood temps while driving. They're not as bad as I expected.

_______________

Date: Fri, 08 May 1998 08:03:58 -0700
From: Spencer Hutchings

(My gauge) reads about 184-205 in traffic around town with 70-80 outside temp.
185-190 on the freeway at 80 MPH
195 on the freeway at 130 MPH

_________________

Date: Tue, 27 Jan 98 13:15:49 -0500
From: "Linthicum, Sandy"

>I'm planning to add an AutoMeter mechanical water temp
>gauge when I have the rest of my cooling system apart soon.

>Also, the tubing is 6 ft long, which seems like it could
>be tight for mounting on the steering column. Has anyone
>had any problem with that length or is it better to go with
>the longer version?

6 ft is to short - you can probably stetch it to fit but it will be in the way and a pain in the a!! forever.. Return it and get the 12ft one.

>From previous posts its seems most people are taping a
>hole on the flat portion of the thermostat housing.
>Autometer makes a 3/8" NPT adapter which I will use.
>Any tips when locating and making this hole?

There is only one logical place for the hole. NPT is a tapered hold, tapped in aluminum alloy. Tapping Aluminum is tricky, so get the correct specialized/trick tapping lube for aluminum and take your time or have someone else do it for you. I would suggest covering the metal capulary tube from the sensor to meter with something (like rubber hose) to protect it from heat & abrasion.

If mounted like I did mine, the new guage will remain at 0(lowest) till the thermostat open and lets hot water start to circulate. Temps will also go way up when you shut off the engine and part (heat soak). Both normal.

Pay close attention if temps go over 230F, they then to exponentally go up very fast from here and you want to keep them under 240F at all costs.

In crusing traffic, just turning on the A/C starts the fan running on low and will drop temps on a hot day from the 225-230F mark to less than 200F in a few minutes.

______________

Date: Thu, 07 May 1998 21:11:33 -0700
From: Smeagol

Thanks to all who replied on my Intellitronix water temp gauge questions. My problem did turn out to be the ground I was using. If you plan on installing this gauge, don't use a ground for the lights unless you want it to act really funny. I moved the ground to metal/frame and it behaved normally. I was also playing around with the dimmer wire on the Intellitronix and found out that the gauge only dims half way. They also confirmed this over the phone. You can set it up to either dim w/the dimmer switch slowly, or just click down to half dim when you turn on the lights. I opted for the second way since I rarely use my dimmer switch.

______________

Date: Mon, 29 Mar 1999 15:28:24 -0600
From: "Westbrook, Chuck"

It is easier to drill and tap a hole in the front of the thermostat housing on the flat surface. This places the sending unit directly in front of the thermostat outlet. The metal there is over 1/2" thick.

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