Oil Pressure Isolator for Oil Pressure Gauge

[Mr. Flibble]

So, I have the sandwich and remote oil filter set for my L400. I also picked up a mtx-d oil pressure & temperature gauge (as well as a RHD gauge pillar pod).

I was looking through the install directions for the MTX-D oil pressure gauge, and there is a warning not to put the pressure sender too near the oil pump as the pulsations from the pump can damage the sender. I noticed that the oil pressure sender that is stock on the 4M40 is quite some distance away from the pump - near the intercooler in fact.

Which brings me to an isolator.

Now, normally, when you use an isolator, it is to keep stuff like fuel from leaking into the cab when you are measuring fuel pressure with a gauge. In this case, I don't need the fluid separation, I only need to "isolate" the pressure sender.

Can I go about this with a long oil pressure line? Would that work? Should I use brake line instead of braided steel and rubber to isolate the pressure sender? How far would be enough?

Or, should I just tee into the same area as the pressure sender with the stock location? (That leaves an unused port on my sandwich.)

The Pressure Gauge and bits:

MTXD_OilPress-ins1.jpg (137.17 KiB) Viewed 3998 times

[sub-arctic]

not sure I am following correctly what you are saying? if you are referring to isolating the pressure sender as in keeping it in the engine bay then yeah no problem. The only time you should have your pressure sender in the cabin is if it is a "wet gauge" so basically a physical gauge measuring the pressure in real time, most gauges these days have a sensor and wires running to the indicator, thus eliminating the need to have fuel/ oil lines in the cabin. from the looks of your kit I would put a tee fitting in where the OEM pressure sensor lives normally and run a line to both the aftermarket pressure sensor and the other part of the tee to the OEM one to get your pressure light reading. if you have a really long run of either flex line or solid tubing to your pressure sensor you may need to bleed the line with the engine running to remove the air, no big deal really but its best to mount it as close as you can, to the source.

Hope this answers your question!

[Mr. Flibble]

not sure I am following correctly what you are saying? if you are referring to isolating the pressure sender as in keeping it in the engine bay then yeah no problem. The only time you should have your pressure sender in the cabin is if it is a "wet gauge" so basically a physical gauge measuring the pressure in real time, most gauges these days have a sensor and wires running to the indicator, thus eliminating the need to have fuel/ oil lines in the cabin. from the looks of your kit I would put a tee fitting in where the OEM pressure sensor lives normally and run a line to both the aftermarket pressure sensor and the other part of the tee to the OEM one to get your pressure light reading. if you have a really long run of either flex line or solid tubing to your pressure sensor you may need to bleed the line with the engine running to remove the air, no big deal really but its best to mount it as close as you can, to the source.

Hope this answers your question!

I wasn't clear in my explanation above. My fault. :/

The installation guide for the oil gauge warns you not to put the pressure sender right nest to the pump. Unfortunately, that was my plan. I have an oil sandwich that is set up for the sender to go right into. But this is probably only 3 inches away from the pump. So, in this case I am looking to "isolate" the sender by adding a longer line, not to keep fluid out of the cab. I could tee in where the stock oil sender is, but I did get the sandwich with oil temp/pressure/bypass in mind.

So, basically, I am trying to figure out where to mount the sender, when I had intended to put in next to the pump, but the directions warn not to do this.

[sub-arctic]

Oh i see what you are saying. I wonder why they recommend that. Maybe because of fluctuations in oil pressure right near the pump? just speculating. It may be worth your while to run a line off of the sandwich adapter to the sensor mounted in another place but I honestly don't see the advantage to this as the oil readings will likely be the same.

Sorry I am not totally sure what to suggest! Personally I would look at a tee on the stock pressure switch because you know thats where mitsu gets their pressure info from. Likely all you would need is a single tee that would fit both the pipe threaded sensors into it and have the tee threaded into the block, unless there are clearance issues of course.

hope this helps!

[Fishtank]

Mr. Flib,

I would just T off your oil pressure switch location, it's accessible and easy to do. That's where I picked up oil supply for my bypass filter and it works great. I don't think you'll have any problems with pressure fluctuations damaging your sending unit.

I think using the port on your sandwich will cause you extra work with little to no advantage.

Just my 2 cents.

[Mr. Flibble]

Mr. Flib,

I would just T off your oil pressure switch location, it's accessible and easy to do. That's where I picked up oil supply for my bypass filter and it works great. I don't think you'll have any problems with pressure fluctuations damaging your sending unit.

I think using the port on your sandwich will cause you extra work with little to no advantage.

Just my 2 cents.

Yeah, you are probably right.

The sandwich already has 3 port holes drilled in it. Oil Temp, Oil Pressure and Oil Bypass - as well as the remote filter mount adapter.

Guess I will just plug the one hole and only use the other 2.

Anyone have ideas of where I can get an appropriate tee fitting for the Deli?

[Fishtank]

Mr. Flib,

I would just T off your oil pressure switch location, it's accessible and easy to do. That's where I picked up oil supply for my bypass filter and it works great. I don't think you'll have any problems with pressure fluctuations damaging your sending unit.

I think using the port on your sandwich will cause you extra work with little to no advantage.

Just my 2 cents.

Yeah, you are probably right.

The sandwich already has 3 port holes drilled in it. Oil Temp, Oil Pressure and Oil Bypass - as well as the remote filter mount adapter.

Guess I will just plug the one hole and only use the other 2.

Anyone have ideas of where I can get an appropriate tee fitting for the Deli?

Pretty standard fitting from any pipe shop or auto supplier.

You will need to get a standard 1/8" NPT T adaptor with 2 female and one male port along with a 1/8" BSP Die to re-thread the male fitting on the T. The oil pressure sensor male BSP threads will fit the female NPT threads no problem but the male NPT threads need to be run through the BSP die before install. You can then run a line from the female NPT port to your new pressure transducer or just plug it directly into the T if it's 1/8" NPT threads, which it appears to be from your picture.

Tough to see, but this is a picture of the fitting for my bypass install (lower right of the picture).

[Mr. Flibble]

Mr. Flib,

I would just T off your oil pressure switch location, it's accessible and easy to do. That's where I picked up oil supply for my bypass filter and it works great. I don't think you'll have any problems with pressure fluctuations damaging your sending unit.

I think using the port on your sandwich will cause you extra work with little to no advantage.

Just my 2 cents.

Yeah, you are probably right.

The sandwich already has 3 port holes drilled in it. Oil Temp, Oil Pressure and Oil Bypass - as well as the remote filter mount adapter.

Guess I will just plug the one hole and only use the other 2.

Anyone have ideas of where I can get an appropriate tee fitting for the Deli?

Pretty standard fitting from any pipe shop or auto supplier.

You will need to get a standard 1/8" NPT T adaptor with 2 female and one male port along with a 1/8" BSP Die to re-thread the male fitting on the T. The oil pressure sensor male BSP threads will fit the female NPT threads no problem but the male NPT threads need to be run through the BSP die before install. You can then run a line from the female NPT port to your new pressure transducer or just plug it directly into the T if it's 1/8" NPT threads, which it appears to be from your picture.

Tough to see, but this is a picture of the fitting for my bypass install (lower right of the picture).

That will work. I suppose I could also move the stock pressure sender to the sandwich as the port is already drilled, then put the sender I have on that spot - mind you, I think I would need an adapter anyways as it is NPT.