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Old February 17th, 2004, 08:35 PM
rover4x4's Avatar
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1995 SW #487/500
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Location: The Old North State
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Oil pressure gage

Have many people here installed one? How hard are they to install?

Poor gas mileage gets you to the best places on earth
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Old February 18th, 2004, 12:36 PM
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Jeffrey Rosbrugh
95 D90 ST #2585
Join Date: Sep 2003
Location: Wrightsville Beach, NC
Posts: 102
I JUST completed this installation. It is rather simple, or so it was on my 95 3.9L. On the oil pump there are (at least) two 1/2-20 threaded ports. One of the ports has the OEM pressure switch for the idiot light. Up a little ways (inch or so) and around back the second port has a 1/2-20 plug. I removed this plug, machined an adapter (more in a second), and then was able to install the pressure gauge sender. Pulled a new wire back to the cabin, pulled power wire from switched source behind the dash, tapped into the light circuit so the new gauge would illuminate, and that was about it. Now the more difficult part: making the adapter. I used stainless 3/4" hex and machined it down on one end to 1/2-20 threads and then cut a hole all the way through and tapped the through hole to 1/8NPT for the new sender. Worked like a champ. I drew it up in Autodesk Inventor if you would liek the drawing I can send it to you, or anyone for that matter. While I was in there, I fabricated stainelss steep hard-pipe oil cooler lines and used a -8AN fitting with stainless braided hose. The only remaining part is the large Banjo at the pump I have not replicated (yet). I sent Chris V a not asking if he wanted it written up, cause I can write the whole thing into a tech article. Let me knwo if I can help.

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Old November 30th, 2004, 08:24 PM
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Trevor Tarr
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Trevor Tarr
1997 D-90 4.6 NAS ST
Join Date: Dec 2003
Location: Altadena, CA, USA
Posts: 171
Does anyone know if the oil pump on a 97 4.0L D-90 has the same extra threaded ports? (It may be I just wasn't looking in the right place, but I don't believe mine does.) That would definitely solve a problem which has vexed me for months: rigging up a t-adapter to run both the OEM idiot-light pressure switch and a sender for a mechanical guage through the existing port.

First problem: the space available there is very limited, so threading together the adapter is not easy. Second problem: every adapter configuration I've come up with leaks (more than the rest of the engine).

Any thoughts?
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Old November 30th, 2004, 09:04 PM
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Chris Davis
94 D90, 88 RRC
Join Date: Nov 2003
Location: Colorado
Posts: 2,104
You can take an old pressure sender, break out the top plastic part, drill it out and tap it, slam dunk.
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Old November 30th, 2004, 09:44 PM
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Hans Haase
The D-90.com Lab Rat
Join Date: Oct 2003
Location: Long Island, NY
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Neo. Did you replace the entire oil cooler line with a hardline, from the pump to the cooler? That gives me a bit of cause for concern. The engine will flex a bit in the engine mounts by design. If you don't have any flexible portion in the cooling lines, eventually something might crack and fail. Just from the "weakest link" standpoint, I'd bet on the fittings going into the cooler would go first. I may be totally wrong, but I tend to design from a worst case viewpoint.

Trevor. Have you possibly considered a T-fitting up where the oil lines go into the cooler? I am thinking about doing that to add a small mechanical gauge for when I am tinkering under the hood. Got that idea from some muscle-car friends of mine. A lot of them had temperature and pressure gauges under the hood so they could monitor things while working on the engine, and they wouldn't have to run to under the dashboard to check things.


Follow-up Post:

Whoops, disregard. I didn't see the "flexible braided lines" part in there, my bad. You've already got it set-up just the way it should be. I really have to start reading posts more slowly.

Hey, what size are the fittings on the oil cooler and pump anyways? I'm due to replace mine, and was about to do the same thing. (you'd probably make a few bucks selling some bolt-in replacements for the stock lines)

My oil line fix

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