I want to know where the best location to install an oil temp gauge? Is it suppose to be near the oil pan to get the most accurate reading? Because there is less pressure? If this is so can u tap in to the drain plug? Or better to use the sandwich adapter, so then would the oil pressure sensor go when the oil galey plug is under the top mount intercooler, please dont flame me cause i have searched for over an hour and no thread whould answer my question and really would like an answer.
thanks
scott

I sandwiched mine so I could remove it later. I did not want an oil sender hanging below the plug were a rock or dead critter could hit it. I mounted both pressure and temp in it and they work fine and seem to be similiar to what others have reported.

You could get a sandwich plate and install both pressure and temperature sensors there.

I decided to make a hole in the plug, tapped it, and installed a temp sensor. Then, I also have a skidplate, so I don't have to really worry about road debris hitting wires or sensor.

The idea is that you want to measure unpressured oil temperature. Higher pressure = higher temperature. That's why most temp sensors are located at the oil pan area.

The optional OEM oil temp gauge uses a drain plug sensor. Not sure if the plug/sensor is available separately and even if it is the sensor would have to be a match for whatever gauge you decide to use, which is unlikely.

hmmm i think ill just get the sandwich thing u think that will be ok there as well mulder, would it be a big difference from if it was loacted at the drain plug?

Use the Subaru part that taps into the main oil galley.

My "sandwiched" temperature has been as high as 214 (hot idle, AC on, in mountains, high ambient temp (85+). Pressure is right around 20-27 lbs in those conditions (Mobile 1 oil). I do not know if that is way off, but in other forums people have temperatures around 190-200 (typical for mine when under power). My pressure (warm & under power) is typically 80-90lbs.

Does anyone know what pressure will trigger the factory oil light?

Sparks i have read that but most ppl use it for the oil pressure, do u think u could get an acurate oil temp reading from there rather than near the drain plug?

Never thought about taking oil temp at the lowest pressure. My GReddy is installed in a tapped drain bolt, I've seen 98C maximum there, usually around 90C on average.

I think the reason many use a sensor in the pan drain plug is that there is usually only one convenient location to place a sender for oil pressure; if you're measuring temp, you've probably alreay got that filled for the pressure sender, so you go with the oil pan. Placing a T in the pressure sender's location increases the chances of having an oil leak, since that area's under pressure; the oil pan plug is a pretty easy seal.

Let me clear something up by asking this question:

Is it ok to get an oil temp reading under pressure?

Yes, it's OK, but why go through the hassle?

Originally posted by armand1
Yes, it's OK, but why go through the hassle?

It seems to me like using the two oil galleries would be the best way/cleanest installation.

Drilling and tapping a drain plug is a pain and it is vulnerable.

A sandwich adapter is $$ and lowers your filter.

There are vendors such as http://www.wrxtra.com/ that vend plugs that are drilled and tapped for senders. I had a galley plug tapped for a sender in a machine shop several years ago for a French car (a Simca, remember those!)and the price was very reasonable (about an hour labor).

Subaru makes a galley plug that has a threaded center, but it's metric (10X1.25)

I already got the gallery adapters, but does anyone know who sells oil drain plugs tapped for a temp sensor?

Get it tapped at a machine shop and use teflon tape.

VDO makes temp senders in a range of thread sizes to replace OEM drain plugs. My Miata uses a 14mm; don't know if they make the bigger Subaru-sized one.

ok thanks for the input

drain bolt threading is m20 x 1.5, omori makes an adapter it's either the P-60 or P-74, but it doesn't have a lip to it so you don't want to use the oem crush gasket. I didn't like it and I just drilled and tapped my stock plug.

Just to add more confusion to the mix. I do not have the scientific background to explain why it is better to NOT measure temperature under pressure. I would imagine the arguement that says, "it's not that much different and it's not that critical" are probably valid. With that said, my car will never see oil temps above 200F no matter how hot, or what conditions (ie. traffic).

I have my sensor in the drain plug, provided as tdxflex stated, the omori part number. It works great for me, and I even use the "factory" (suppled with my oil filters) crush washer, and so long as you put it on correctly, I have not experienced a leak. (though when you put it on backwards, you DO experience a tiny drip... not that I would know or anything ;) )

Anywho... I did the oil pres. using the stock galley plug, and that works just fine. I'm sure the sandwhich adapters are good, though is it possible they get in the way during filter changes? I know for my omori, I WAS worried about it catching on something, but that thing is STRONG so I have no fear about it getting ripped off, and I've had it on now for about 10,000 miles. I just pop the clip off of it, unbolt it, and change the oil as normal. Just my .02 YMMV and all that.

Does anyone know what the ranges of oil pressure & temperature are for a stock WRX? I have a SPA digital dual guage supposedly accurate to .1 F and lb and I get over 200F in hot weather with the AC on in stop and go traffic.

I also on one or two occassions have gone over 100 lbs pressure.

Thanks

Where do you have your sensors mounted?

In a sandwich adapter, electrical senders. I insulated the wires with foam insulation wrap and a split loom. The temperature does not seem to correlate with pressure.

Originally posted by igo380
Get it tapped at a machine shop and use teflon tape.

Do not use teflon tape if the senders ground is to wherever you are placing it.

It is OK to measure oil temperature when the oil is pressurized. This will not affect the temp. reading. I think folks must be thinking of the ideal gas law which states that higher pressure causes higher temperature. This is not the case with incompressible substances, like oil.

My WRX shows max oil temp of 215F (taken from the plug location under the intercooler), and max pressure of 100 psi (limit of the gauge). Warm idle is ~40 psi, warm cruise is ~90 psi

. With that said, my car will never see oil temps above 200F no matter how hot, or what conditions (ie. traffic)

If you drive hard you will surely see oil temps ove 200F. After a 45- 50 second Autocross run I see about 215F. Normal highway about 185 and sitting around on a hot 90degree day can be about 195. This is tapped through the drain plug.

Oil pressure will be HIGHEST, about 100PSI when the oil is cold. Warm idle I get about 25 PSI, warm cruise about 75 to 80 on Mobil 1.

Typicaly if you have 10 PSI per 1000 RPM you are OK. The factory light will not signal until you are around 7PSI of oil pressure.

G

So if I get this right, the best place for the oil pressure sensor is on the galley plug under the intercooler, just buy the threaded plug from the subaru dealer. My questions is: I'm planning on buying an electric oil temp gauge and I'm a little confused as to where is the best place to install the sensor. After all the searching, it looks like a lot of people are installing it in the drain plug. Does anybody know where the factory sensor is installed?? I'm actullay looking for the easiest and cleanest install.

Originally posted by john wadsworeth
There are vendors such as http://www.wrxtra.com/ that vend plugs that are drilled and tapped for senders. I had a galley plug tapped for a sender in a machine shop several years ago for a French car (a Simca, remember those!)and the price was very reasonable (about an hour labor).

Who else besides wrxtra sells this stuff? (I dont feel like goin g to a machine shop)

WRXTra is unresponsive.

egauges.com might, omori-na.com and autometer might also. I overlooked that option, they should make m18 x 1.5 bolts already drilled and tapped 1/8 npt because the oil galley plug is the same size as a toyota oil pan drain bolts.

http://www.omori-na.com/catalog/accessories/accessories.pdf

P-72, m18 x 1.5 male threading, 1/8 PT female threading. It says 1/8 PT, but I have a feeling they'll have a NPT version if you call and ask, especially since this is the north america website and I think Omori north america sensors have npt threading instead of bspt. Not positive, but you can look for some from Toyota parts vendors, just have the threading identifications handy when you ask around.

If you don't have any luck finding one, you can either do the 1/8 PT to 1/8 NPT adapter, but that's annoying buying two adapters, or go on your local boards and see if anyone can hook you up.

Originally posted by tdxflex
egauges.com might, omori-na.com and autometer might also. I overlooked that option, they should make m18 x 1.5 bolts already drilled and tapped 1/8 npt because the oil galley plug is the same size as a toyota oil pan drain bolts.

http://www.omori-na.com/catalog/accessories/accessories.pdf

P-72, m18 x 1.5 male threading, 1/8 PT female threading. It says 1/8 PT, but I have a feeling they'll have a NPT version if you call and ask, especially since this is the north america website and I think Omori north america sensors have npt threading instead of bspt. Not positive, but you can look for some from Toyota parts vendors, just have the threading identifications handy when you ask around.

thanks!

To my knowledge Omori-NA is no longer able to source Omori's per the site in Japan the American supplier is Omori USA.

Try this guide out:

Oil temperature and pressure sender installation. (http://www.turboice.net?guides/guides.htm)