Billat908@yahoo.com

My oil pressure hole is very very close to a US 1/8 27 NPT. The BSPT is 1/8 28. This is way smaller than the coolant temp sensor.

Billat908@yahoo.com

That's a tough one.

I have no way of checking a 3/8 BSPT, but it would seem that the OD that I measured of my sensor would indicate it would go in a little farther than 3/4 turn.

My thread gauge has nothing between 1.25 and 1.5 mm. The old sensor fits the 1.5 gauge almost perfectly, according to my lousy eyesight. The threads have an OD of .6243, which is a trifle under 16mm. The threads seem not to be tapered, as far as I can determine considering the short length of the threads.

The sensor fits nicely into a M16x1.5 nut, threading smoothly and with no wobble all the way in until it bottoms out (with the O ring removed).

I am at loss here, unable to even guess why the old sensor and the new sensor only engaged by less than one turn. The presence of both black goop and teflon tape tells me that previous mechanics dealt with this, as well. The threads did not show any obvious buggering, but the location made inspection difficult.

The M16 X 1.5 plug tap engaged willingly, but took a little more force to turn all the way down than one would expect just chasing threads. I suspect the hole was tapered a little too tight, probably from not running the tap far enough down at the factory. This would explain the sensors just barely starting. I cannot even begin to guess the function of the shelf part way down the hole. Since the sensor had an O ring, it would seem that the shelf was not for sealing, like an aftermarket mechanical sensor. I can't remember if the new sensor has an O ring or not.

Billat908@yahoo.com

The way the tap bit into the metal, I think I was making parallel threads out of tapered threads. I used special aluminum cutting oil, so it came out pretty smooth. Anyway, the threads on the sensor seem to be sealing, so no leaks and good readings. I will keep an eye on it for leakage, and will use some Permatex or teflon tape if it leaks. So far, so good.

scope103

It turns out I have a TVV (thermal Vacuum Valve) sitting around. I measured it with a caliper, it is definitely tapered, and within the limits of my measurement I'm convinced it's 3/8" BSPT. In the 3VZE the TVV is in the same manifold as the temperature sensors, so I'm pretty sure your temp sensor has the same thread.

Here's a source for that tap; at $72.00 I plan to never need one.

Billat908@yahoo.com

What ODs did you measure?

Mine is straight per micrometer measuring.


Heck, I don't even know if my 22RE has one of those.

Both the old and new temp ind sensors thread easily into a M16 X 1.5 nut. The nut is the standard Chinese hardware store offering, so the fit is a little loose, though. The looseness does not increase as the sensor is turned in, so there is no indication of a mismatch or a taper. Of course, the real test would be a quality die instead of a Chinese nut. The sensor threads are not tapered, having an OD of .6243" for their full length.

My thread gauge checking showed them to have a 1.5mm pitch. My thread gauge has nothing between 1.25 and 1.5mm. The 19 TPI 3/8 BSPT works out to a metric thread pitch of 1.33mm.

My US thread gauge does not have a 19 TPI blade, but does have both 18 and 20. Checking the old temp sensor shows it to be between 18 and 20 TPI. The 18 seems to be a closer fit than the 20.

The way my M16 X 1.5 tap bit into the manifold makes me think the hole had tapered threads.

scope103

0.643 and 0.660. There's no point trying to calculate the actual taper from my measurements. The entire threaded portion is only 0.400 long, and to measure close to the ends I would really need a thread micrometer (which I don't have). But the threads on the TVV are in good shape, so I'm convinced that it is tapered.

I don't have a 19tpi gauge either (what IS it with the British?). 1.25mm, 18tpi, and 20tpi: all are close, none are the right one. I "counted" the threads using a linen tester (magnifier with a scale) and got 4 1/2ish threads over a 1/4". So it COULD be 19tpi.

The TVV is also sometimes called the BVSV (Bi-Metallic Vacuum Switching Valve). When the engine warms up, it puts vacuum on the vapor canister and sucks the vapor into the intake.

Billat908@yahoo.com

My old and new sensors measured at 0.6243", (with parallel threads) which is a bit smaller than your sensor. This was measured with a high quality micrometer.

And yet the hole in my manifold was apparently even smaller than that. Or has slightly different thread pitch, as both the new and the old sensors just went in less than one full turn. Because of its difficult location, it was very difficult to get a thread pitch measurement. But, reading the pitch of a threaded hole is always difficult, anyway.

It is interesting to note that my sensors threaded into a 5/8-18 die almost exactly as far, and with the same feel as they threaded into the manifold before I chased the threads with the M16 X 1.5 tap. This makes me think that the manifold may have been tapped for 5/8 18. That makes as much sense, or more than any other idea. No idea how, when or why. The engine was replaced before I bought the 4Runner.

I had no idea I was driving the 4Runner for over 10 years with a sensor just barely in the hole. YEEKS! I think of all the super-isolated trails in CA and AZ we have been with that vehicle, and am really glad we now have a sensor that is really threaded into the hole securely, even if I still don't know what's what.

long-haul

Sounds like I am having a similar issue and I wonder if you could report back on how your fix worked? Here is the tap I am thinking would be required.

http://www.vermontamerican.com/Produ....html?CID=4087

The area I am working on is the dual-tipped vac fitting on the top of the intake side, between the EGR and the fuel pump. When I unscrewed it, I found out it's got coolant in there and is some kind of thermo vacuum fitting.

Thank you!

millball

Most tapered pipe thread fittings on Japanese cars, not only 'Yotas but also Nissan, Mazda and others is BSPT (British standard pipe tapered)
There is also a BSP (British standard pipe) thread standard that is not tapered but that thread is very, very seldom seen.
Although these thread sizes are found in otherwise all metric standard cars, BSPT is not truly a metric thread.
They are 1/8"- 1/4"-3/8" pipe, ect, just like american standard pipe.
BSPT is 'off' enough that American pipe thread fittings will not fit correctly.
In the big picture, BSPT is a fairly commonly encountered pipe thread, especially on Japanese cars, and reasonably priced BSPT taps and dies can be got if you shop around.

MudHippy

Ummm...yes? But, technically speaking, no. I have enough posts with the correct info in these regards. Just posted another one minutes ago(different thread). You search, you find.

HINT: The Japanese have their own Industrial Standard.

millball

Mudhippy is certainly semanticly correct, but in this world of Global standardisation, The Japanese have lost out; in the pipe thread standard arena, at any rate.
The Japanese standard is obsolete, having been superceded by R, Rc, Rp, and G ISO standards. Japanese standard and BSP being substantially identical.
Just try to find a Japanese standard tap at any reasonable price.
BSP is everywhere.

http://www.engineeringtoolbox.com/th...rds-d_776.html

rjf

Thanks for this thread.

I pulled the coolant temp sensor on my 93 pick up 22RE. The old sensor or the new sensor would not screw back in. Bought a 16 x 1.5 bottom tap $18 and chased the threads. This cleaned the grit out and allowed both sensors to properly engage. There was no cutting of new threads. I only used a small 4" adjustable wrench to spin the tap.

Hope this helps someone else

mechkw

Resurrecting this old thread. I am having the same issue and read all these and came up with my own take on this. Measuring the sensor and the hole, I came up with a 16x1.5 with the old sensor, a new sensor and the hole in the intake. They do not appear to be tapered as my measurements do not indiacate a taper. Why it/they won't thread back in --- who knows. I personally pulled the sensor out before it all went to the machine shop for cleaning and machining. I had the intake cleaned of all the crud through the EGR system and the bottom side of the intake made sure to be flat and reseal with the plate (car'b intake). The new sensor and old one for that matter came/come with an O-ring on the outside to seal it up. I did however find that there was some sort of sealant on the old threads in the intake. I guess I'm shopping for a 16x1.5 tap to get this to work, bummer that I already installed the intake to the head, so I have a little bit of a struggle behind the fuel pump.

scope103

You can see my comments and those of others above. We don't think these fittings have metric, or NPT, threads. Rather they're BSPT (3/8"-19), or as they are now known in the Japanese world, PT-JIS. https://trimantec.com/blogs/t/thread...guide#PT-Chart

Your measurements are "close" to BSPT/PT-JIS, just as 3/8" NPT is "close." If you use enough pipe dope, I wouldn't be surprised if over-tapping it with a M16-1.5 would work. It also wouldn't surprise me if it leaks.

Up to you.

mechkw

I am not getting any measureable taper out of either the sensor or the hole in the intake that would indicate a pipe thread.


EDIT: specs in print in the NAPA book for sensor TS6013 which fits from 1980-1992 is saying the threads are 16x1.5

EDIT-2: another parts store I deal with that specializes in Imports also verified the thread size as 16x1.5 in his Toyota books

EDIT-3: Well the tap I ordered (16x1.5) came into the store so I went and picked it up. Not a bottoming tap as mentioned before. I started the tap with my fingers, then had to use a 12pt socket to grab the rest with a ratchet. Threading in was super easy and it was cutting very slightly. I cleaned out the hole and started the sender with my fingers and finished up with a 17mm deep socket. It went in about 2-3 threads with fingers and the other 3 threads it started to get snug, not extreme, but you could feel the slight pressure which leads me to believe the sender is correct, but the hole in the intake has a slight taper to help seal the threads? It went in without any real issue and sealed up against the o-ring no problem. So there is my experience