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View Full Version : How to: make your own coolant sensor adapter



Matz
01-08-2006, 10:37 PM
This how to will be in flux, as I figure out what pieces are needed to create a good coolant sensor adapter.

In summary, when adding a coolant sensor to your car, you'll want to get the most accurate temperature available. GReddy actually sells a 36mm sensor adapter that installs in-line with one of the radiator hoses, as shown below from MarkSAE's car:

http://www.norcalevo.net/gallery/albums/album385/DSC06634.sized.jpg

42 Draft Designs just released a thermostat housing replacement that has a bung welded in for easy sensor installation:

http://www.42draftdesigns.com/images/evo/watertemp2.jpg

The problem with both approaches is that the sensors are placed downstream of the thermostat. In the event of a failure, if the thermostat fails closed, no coolant will reach the sensor, and you won't be able to get an accurate measurement.

So what do you do? As MarkSAE pointed out on evom, you'd have to install the sensor before the thermostat, so you'd have to tap into the hose marked by #10718 in the following image:

http://forums.evolutionm.net/attachment.php?attachmentid=81605&stc=1

Big thanks to WarmPepsi on evom, who came up with his own home-brew coolant adapter, which looks very nice for mixing and matching hardware store parts. His looks like this:


http://forums.evolutionm.net/attachment.php?attachmentid=81458

Unfortunately, he didn't have a parts list available, so I decided today that I'd just go to Orchard Supply Hardware and pick out whatever I could find that makes sense. Here's what I came up with so far:

Parts list:
- (1) 1/4" NPT brass tee
- (2) 3/8" barb x 1/4" NPT brass fittings
- (1) 1/4" NPT to 1/8" NPT brass reducer
- (1) 1/4" NPT brass elbow (possibly optional)
- teflon tape
- (2) hose clamps, currently unspecified

These are the images of the parts I got from OSH, shown in bags so you can find the same pieces more easily:

1/4" NPT brass tee:
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/t_bagged.jpg

3/8" barb x 1/4" NPT brass fitting:
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/barbed_fitting_bagged.jpg

1/4" NPT to 1/8" NPT brass reducer:
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/reducer_bagged.jpg

1/4" NPT brass elbow (optional)
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/elbow_bagged.jpg

Here are the pieces out of their bags:

http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/t.jpg
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/barbed_fitting.jpg
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/reducer.jpg
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/elbow.jpg

and here's the GReddy temp sensor:
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/sensor.jpg

Ok, now on to the assembly:

Step 1: screw reducer into one end of tee
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/step1.jpg

Step 2: screw sensor into reducer
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/step2.jpg
The sensor needs to go into the end so that it'll be in full contact with the coolant:
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/sensor_view.jpg

Step 3: screw barbed fitting into opposite end of tee
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/step3.jpg

Step 4: screw other barbed fitting into elbow
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/step4.jpg

Final step: screw elbow into tee
http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/final_assembly.jpg

I think the elbow will end up being optional, so you can probably just screw the barbed fitting into the last opening in the tee. It would then look like this:

http://www.initialdproject.com/evo8/HowToMakeCoolantAdapter/final_assembly2.jpg

You should probably use teflon tape on all threads, just in case.

Because the barbed fittings are a bit long, I'm thinking about taking off a couple of barbs on the lathe, and then machining the two barbs closest to the NPT thread flat, just leaving one barb. I figure that I'll want to use hose clamps anyway.

FYI, I haven't actually installed this piece yet. It's a bit bulky, and I wanted to get everyone's feedback (especially WarmPepsi's) about my instructions. Please post any questions or comments on this.

wilson1
01-08-2006, 10:50 PM
wow, u really's going to do it!

Nice! :D

MarkSAE
01-09-2006, 01:00 AM
Good work Dave! The only thing I don't like are those barb fittings cuz once you put the hose on, you pretty much have to cut it to take it off. They're a pain to work with.

When installing my Helix IC pipes, I changed out the barb fitting for a beaded one shown below. I was able to find the beaded fittings at Kragen. I think I've seen some at Napa Autoparts too.

Since you have access to a lathe at work, converting one of your barb fittings to a beaded one should be easy. ;)

http://www.norcalevo.net/gallery/albums/album239/DSC04108.sized.jpg

Matz
01-09-2006, 06:53 AM
When installing my Helix IC pipes, I changed out the barb fitting for a beaded one shown below. I was able to find the beaded fittings at Kragen. I think I've seen some at Napa Autoparts too.

Since you have access to a lathe at work, converting one of your barb fittings to a beaded one should be easy. ;)

Thanks! Man, I'm surprised how much useful stuff you can actually buy at Kragen. WarmPepsi also told me to go beaded... I would do that, but like you said, it's a simple face and turn operation to convert my fitting to the bead type. I'll post pics if I don't f it up. :lol:

Matz
01-09-2006, 06:28 PM
umm... yeah... so I guess I'll be buying the beaded fittings from HD or Kragen. :D Couldn't grab the workpiece very well on the flats, so the finish looks like crap. I'll post embarrassing pictures later.

Here they are:
http://www.initialdproject.com/Evo8/HowToMakeCoolantAdapter/bead_conversion.jpg

Matz
01-12-2006, 12:51 AM
Home Depot's tee and reducer are way nicer looking than OSH's. I still need to go to Kragen to get the bead fittings, though. HD has hose clamps that should work.

New tee and reducer, plus hose clamps:
http://www.initialdproject.com/Evo8/HowToMakeCoolantAdapter/newstuff.jpg

Not a lot smaller than OSH parts, but a heck of a lot nicer looking:
http://www.initialdproject.com/Evo8/HowToMakeCoolantAdapter/comparison.jpg

earlyapex
01-12-2006, 01:19 PM
Much nicer, now your engine bay won't look like the backside of my toliet. :lol:

Matz
01-12-2006, 02:39 PM
Much nicer, now your engine bay won't look like the backside of my toliet. :lol:

At least not until I install my bling bling BOV with the toilet trumpet installed. yeah baby.

Matz
01-14-2006, 05:22 PM
FYI guys, I went to Kragen today to get the new fittings. Of course, they didn't have the 1/4" NPT to 3/8" hose fitting, so instead of going to another Kragen, I went to the Home Depot next door to get a 1/8" NPT tee. Do NOT do this. I screwed my temp sensor in, and it pretty much obstructs most of the fluid flow. I'm back to either using the modified barbed fittings, or going to another Kragen (which I'll probably do first).

After all of this, I've spent enough to *almost* cover the cost of the fancy 42 Draft Designs thermostat housing. However, that piece has limitations that were discussed earlier, as well as on evom.