Oil sending unit for m38

[11cgrunt]

OK. I dont really know how to ask this question. But here goes. i have a new oil pump. and im converted to 12 volt. my oil pressure is low. zero at an idle. The oil sending unit that is mounted on the side of the engine,is it nesasary for it to be used for my 12 volt guage. or can i hook it up directly to the 12 volt gauge and get a proper reading? I have a brand new 12 volt gauge and oil pump. So do i need to use the sending unit.

Matt R
_________________
U.S Army 1989-2006 Airborne Infantry
8-51 m38
My jeep doesn't leak. its just marking its territory.

[Cacti_Ken]

Yes you need the correct sender and gauge combination. I'm assuming you have a 24 volt sending unit and are trying to wire it to a 12 volt gauge. it probably won't be accurate if read at all. Do you know what voltage the sending unit is that you are trying to mate with the 12 volt gauge?

Why don't you get a known good mechanical gauge to test your oil pressure that way you have a base line to work from when you install the correct electrical stuff.
_________________
Tropical Veteran
35th Inf. Reg. "CACTI" 4th I.D. VN
Amateur Radio K5XOM

[11cgrunt]

Im not using the sending unit. Ive gone straight from the block to a gauge. Do i need to use the sending unit. with my 12 volt gauge.

Matt R
_________________
U.S Army 1989-2006 Airborne Infantry
8-51 m38
My jeep doesn't leak. its just marking its territory.

[Oldsalt]

If your gauge has a small tube leading from the engine to the gauge then it is a simple mechanical gauge, and it does not use power. No sending unit needed.

[11cgrunt]

That's what i needed to know. It doesn't state anything like that in the manual.
I didn't know if it is why i have low oil pressure.

Matt R
_________________
U.S Army 1989-2006 Airborne Infantry
8-51 m38
My jeep doesn't leak. its just marking its territory.

[wesk]

Matt,

If you have a 12 volt M38 then the 24 volt info in the M38 manuals is of no use to you.

Oil Pressure
Can you confirm for the audience that your new oil pressure gage has a metal or nylon tube running from the back of the gauge to the 1/8" pipe threaded hole on the lower left side of the engine? If it does it is a mechanical gauge. Now does it have a wire for a lamp inside the gage? If it does just make sure that bulb is a 12 volt bulb.

Now how about the other three gauges?
Now to go a step further the rest of the 24 volt gauges will not work for you either.

Gas gauge
You will need a 12 volt fuel gauge and sender and it is best to buy both from the same manufacturer. Aftermarket 12 volt senders will need adjustments made for miss matching mount holes in the top of the tank and length and direction of swing on the float will need to be adjusted to your tank.

Coolant Temperature Gauge
For the water temp the best units are the mechanical type with a capillary tube integral to the gauge. Again if it has a wire for the lamp make sure the bulb is 12 volt.

Electrical charging system gauge
I assume you have a 12 volt alternator. If this is true then the fourth gauge will need to be a volt meter. Usually marked 0 to 16 or 18 volts. The plus wire for the gauge is connected to the run / ignition side of your ignition switch and again if it has a wire for a l;amp make sure the bulb is 12 volt. If you have a generator then either a volt meter or amp meter can work for you but the simplist to use is the volt meter.

Speedometer
If you are using your original speedo then it has no internal lamp. You will need to replace the bulbs in the two instrument cluster illumination lamps with 12 volt bulbs.

High Beam Indicator
Your high beam indicator lamp will also need to be converted to a 12 volt bulb.

Now Back to your LOW oil pressure

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