Oil galley temp reading low
 

Hi,

installing my oil cooler i hooked up my greedy style oil temp meter using the oil galley plug method. What i found out later, this location is not really suitable for accurate temp readings, see below.

Sensor mounted in the galley plug using an adaptor (compared to the Open Flash Tablet readings):
http://thi.uloz.to/6/3/4/6349ebca939...e2.640x360.jpg
204F equals to 95C, but the gauge shows 87C :iono:

Thinking that the gauge our the sender could be inaccurate, i´ve replaced the stock oil press switch with the sensor, and hey presto!..temps are now correct. (they should be, as the stock sensor where the OFT gets the reading is next to it).
See:
http://thi.uloz.to/0/a/9/0a9ecb67bb9...2f.640x360.jpg

Gauge sensor instead of the switch:
http://thi.uloz.to/6/a/2/6a2cf6f3386...a8.640x360.jpg

Switch in the galley plug:
http://thi.uloz.to/f/a/5/fa5fcdaaac7...8c.640x360.jpg

And finally, my bit of gangsta oil cooler sandwich plate install :bonk: But it works.
http://thi.uloz.to/b/b/3/bb319297607...ff.640x360.jpg

Thank you for sharing your experience, and finding.

Interesting. I installed an Innovate oil temp sensor in the same location (stock oil pressure switch) and it reads 15-20*F higher than the OBDII. Curious to know what other people who are reading oil temp there are seeing.

I will check today. This peaks my interests, as I noticed that I never get my oil above 200F even driving somewhat hard. Though I installed my oil temp sensor in the galley because it was too large to fit in the adapter to change thread pitch(to install in the block).

Edit: I did some testing. Looks like my temp gauge in the Galley is anywhere from 20-48 degree F lower than the OFT is reporting.

bump for this! Anyone else?! I've got this same issue...temps for me are 5-19F off

I'm comparing oil temps from obdII and the galley plug sensor

Which one is higher for you?

the obdII is higher...and I feel more accurate. The temp reading seems to fluctuate pretty quickly when doing a wot pull/sitting in traffic. Not "too" quickly, but it seems to respond faster.

My readings from the oil filter area versus what OBD reads is almost the same.

~75-85C at normal freeway speeds. Both read the same.

-alex

That is because the Factory sensor is right under the Oil Filter (Don't mind all the oil, it was a picture from when my sandwich plate bolt came loose and sprayed oil everywhere)

https://scontent-dfw1-1.xx.fbcdn.net...83&oe=577A15A6

I have yet to install my Defi racer oil pressure and oil temperature gauges. I was planning to use two of the oil galley plugs. Maybe the one on the front and one on the back. I believe there are more like one down low but Im not sure where or what would be the best or most accurate place. I bought two galley plugs with the NP holes. Id rather not remove the stock sensors if I can avoid it.

Oil galley was about 20 degrees cooler than OBD2, moved to TRD sandwich plate and now gauge reads about 8-10 degrees cooler.....Depo gauge and Torque app with custom oil temp PID. I emailed Depo and they said Torque/OBD2 was wrong :D

Do you think there is some truth to their claim that the stock sensors may be inferior?



On another note, I found this diagram; seems that there are three oil galley plugs, front-top, back-top and front-bottom, all having part number 11024:

http://parts.subaru.com/images/parts...0_00401229.png

When standing the human body has higher pressures the lower you go because the weight of blood stacked on top of blood is cumulative. Likewise, the pressures at the top may not be the same at the bottom. This too can be the case for the temperatures; a person with a fever may not have the same temp at the armpit as they do at the throat, forehead or rectum, and so could be the case with the engine. As a medical professional, that is how I see it, and what may matter most is not what is the absolute value, but how things are trending.

In the case of the gauges, I want to monitor trends and absolutes. Considering the locations as a comparison to a human, the lowest blood pressure will be at the highest location and the furthest from the heart. For the car, the location that is the highest on the engine and furthest from the oil pump would most likely have the lowest oil pressure, and as such is the case, would be where one would want to monitor pressures to avoid some absolute minimum value. If I am correct with my assumption then the best oil plug to use would be the rear-top plug because it is furthest and highest from the pump. If any oil galley plug is located in a lower pressure cavity then this assumption fails.

For the temperature sensor, the thing to avoid is the absolute hottest temperature--not the average--and to avoid getting on the car when the engine is still ice cold. So along with looking at trends, I want to make sure the hottest part of the engine won't get hotter than a given high value, and that the coldest part isn't too cold to get on it. Deciding where to put the sensor seems trickier, but in most scenarios, deciding when the engine is warm enough to race is easier and less risky than not knowing what is the highest engine temp. So if I want to put the sensor in the hottest place then closest to the heart, or in this case, closest to the oil pump, might be best. And even though heat rises, maybe closer to the bottom is better where the majority of the oil sits and where the exhaust leaves the engine, so maybe front-bottom.

So how does that sound? Too much thinking or reasonable?

As far as pressure readings go. You want to know your highest pressure which in a mechanical system is right after the pump.

For oil temperature I personally would rather know the hottest temperature rather than the average. As overheating the oil is worse for engine health than not waiting until the oil is all the way up to temp.


Just my two cents

This has been something thats been bothering me for quite awhile..

I too have my temp sensor in the Oil Galley plug which does read lower than the ECU itself does.

However im unable to install the temp sensor under the oil filter due to the probe size using the required adapter, so my pressure sensor is there. I've asked before but have been still looking for a good answer to if thats okay or how to remedy it.

I am old school and have used analog gauges that the needle covered more of a difference than you are worried about. Is the temp going up, down and is it very hot.
I learned about how my engine reacted to driving type and ambient temp and only worried if I saw some large abnormality.

Why the highest pressure? If some area of the engine is seeing low pressure then that could cause engine failure. I don't even know if too much oil pressure is possible.

So we agree that monitoring the highest temp location is best, but where would that be, or is the difference not enough to matter?

This was my thoughts as well. Are things trending in the bad direction, and if so, how fast? That and, in the case of oil pressure loss/failure, 'wow the needle just crashed'. With that said, it would be great to know the error and in what direction it is, and to be of the least variance as possible. Like how changing diameter on tires effects the speedo, if I know the variance and if it is up and down I can make corrections to how I read the gauges.

The way a cars oiling system functions your highest pressure location will be the best because you want to know if you are generating enough oil pressure before it enters the rest of the passages in the engine. If something down stream fails you will see a drop in pressure at that location because changes in pressure will travel up stream.

Overall you pressure is mostly going to be linked to oil temperature, as oil heats up it thins out and your engine will generate less oil pressure. If you have mechanical failure you will see a drop in pressure from that as well regardless of where you monitor the system.

For the temperature, in general it's all going to be about the same unless you are running an oil cooler. In that case pre-cooler is the best location.

This is good stuff, thanks. It makes sense, closest to the pump because everything else is down stream from that location.

http://parts.subaru.com/images/parts...0_00401229.png

Looking again at this diagram, it isn't clear if any of the oil galley plugs are accessible. I know the top one is accessible, but today I looked and the rear plug is blocked by the transmission, I think. I believe this is it, between 10 and 11 o'clock behind the plate. Regardless, it is not accessible the the one in front is. I'm guessing the bottom plug is buried in the oil pan, and anyways, I don't want to drain the oil to install this sensor.

http://i6.photobucket.com/albums/y21...ps8aecd7d7.jpg

Which means, I'm going to use the top oil galley plug for the oil temp, and I plan to by brass tee fitting to tee into the stock oil pressure sensor location.