club.liberty.asn.au

Hi all,

I'm planning to buy a Defi oil pressure and oil temperature gauge for my Spec B Liberty 3.0L.

I've found where the stock oil pressure switch is (right behind the oil filter) and plan to remove it and replace it with the Defi pressure sensor.


My question is where is the best place to monitor the oil temperature from? I don't want to use a sandwich plate, I'd like to monitor it from somewhere in the engine block to get a more accurate reading.

I assume I'm looking for a hex plug bolt similar to this (not sure if this particular one is the right one to use though - this one is on the front of the engine near the oil dip stick, behind the belts):


I've got the workshop manual PDF but it doesn't mention it anywhere. I don't really want to remove any of the stock sensors (unless they can work in conjunction with the Defi sensor somehow...)

Found heaps of info on where to find these on GT/turbo models but not on the H6.

Any help is appreciated.

I would suggest using the stock position next to the oil filter, or get a hole threaded into the sump. The stock one I believe reads the temperature before the filter, and therefore before the cooler IIRC.

No, do not put holes in your sump! The correct solution is to run an oil filter sandwich plate. This goes between the engine and the oil filter - so fit it next time you change your engine oil. The fittings that come with Defi gauges will fit the 1/8PT holes in most sandwich plates. Most plates have either two or four holes, which is enough for the two Defi gauges. If I remember the Subaru needs an M20 thread for the centre. Just ensure the tip of the sensor doesn't touch the metal of the sandwich plate, or you'll get inaccurate temp readings.

My GT is running one of these with two o-rings. It's cheap but does the job. http://www.ebay.com.au/itm/ws/eBayISAPI ... 0628519195

BTW if you take out your stock oil pressure switch the oil light will be on!

Stu wrote:No, do not put holes in your sump!

Why not? I've seen sumps modified in alot of different ways and as long as you do it correctly there isn't any danger. As with all modifications. This would be the least drastic sump modification possible.

Stu wrote:BTW if you take out your stock oil pressure switch the oil light will be on!

You can wire your way around this.

So what sort of oil pressure will your sump provide? something pretty close to 0 psi? admittedly oil temps will be pretty much the same as at the filter.
For all the hassle of ripping off the sump, welding and resealing VS installing a $50 sandwich plate!

Yes, you could wire out the oil pressure light too, or even install a brass 1/8PT T piece to achieve both.

The only downside IMHO with using a sandwich plate is the Subaru exhaust manifold/headers gets pretty close to the wiring, so you should really use a foil heat sleeve to be ultra safe.

Admittedly I did glance over the fact the defi does pressure too.

Dump would give a good temp reading but no pressure.

Stu wrote:My GT is running one of these with two o-rings. It's cheap but does the job. http://www.ebay.com.au/itm/ws/eBayISAPI ... 0628519195

BTW if you take out your stock oil pressure switch the oil light will be on!

That sandwich plate sounds ok. I was trying to avoid that, but will do it if I have to.
I already removed the pressure sensor temporarily and put my key to ON (but not start the engine). The Oil light doesn't light up at all anymore. So hopefully it'll just stay off when removed. I intend to put the pressure gauge sensor in where the stock pressure switch was. But I'll just ground it permanently if needed to bypass the light always being on.

Oil temperature was the only one I wasn't sure off. Putting it in the sandwich plate will give less accurate readings as it will be after the stock oil cooler - so temps will be a few degrees less.

In the GT model (turbo) engines there's an oil gallery located under the intercooler according to the forums. I was hoping for something similar in the 3.0L N/A?