How To Install A Mechanical Oil Pressure Gauge? (With Video)

Not a lot of people realize how important the oil pressure gauge is. This is one of the instruments on your dashboard that you always need to be aware of because how you need to make sure that the oil pressure is always at normal levels or else your engine might end up getting damaged.

That said, if your oil pressure gauge is faulty or damaged and is in need of a replacement, how do you install a mechanical oil pressure gauge?

To install a mechanical oil pressure, do the following:

  • Look for the oil pressure-sending unit
  • Look for the double male-end compression fitting in the new gauge
  • Slide the compression nut into the tubing
  • Route the tubing into the passenger compartment
  • Route the oil tube to the gauge bezel
Mechanical motor oil pressure gauge
Mechanical motor oil pressure gauge

It is important to note that installing a mechanical oil pressure isn’t really too difficult especially if you know your way around your vehicle.

As such, if you don’t want to spend money on a good mechanic, you can just simply follow our instructions below so that you will be able to properly install a mechanical oil pressure gauge on your car without any problems.


How does a mechanical oil pressure gauge work?

One of the most important gauges on your dashboard is the oil pressure gauge because of how it involves the overall health of your engine.

In that regard, you need to know that the oil pressure is responsible for checking how high or low your oil pressure is because too high or too low can damage your engine.

It is also a good idea to learn how the oil pressure gauge works because you may need to replace it sometime in the future in case you do end up with a damaged or faulty oil pressure gauge but there is no mechanic that’s nearby to replace the gauge for you.

So, how does a mechanical oil pressure gauge work?

Mechanical oil pressure gauges are pretty much straightforward in how they work because these gauges literally rely on the pressure from your engine. This is why it is easier to understand the way mechanical oil gauges work in comparison to electronic ones.

What happens is that oil is sent to the gauge by tapping in the engine’s oilway and a pipe. The same pipe enters the passenger compartment through a hole in the bulkhead and is then joined on the back of the gauge.

The gauge has a flexible coil tube that has an open end that is mounted on the gauge’s outer part. Meanwhile, the other end of this tube is closed and is linked to the bottom of the needle, which is mounted on a pivot to allow it to move depending on the oil pressure.

From there, oil is fed to the tube at the same pressure that it had when it left the engine. This flexible tube will now straighten due to the pressure and will force the needle to move around the gauge due to the pressure that is exerted into the flexible tube.

How do you install a mechanical oil pressure gauge?

Now that you know the basics of how a mechanical oil pressure gauge works, let’s now look at how you can install it. And since you already understand the basic mechanism of this oil pressure gauge, it will now be easier for you to install it in your car.

Step 1

The first thing you need to do to install a new mechanical oil pressure gauge is to look for the oil pressure-sending unit on your engine. This will vary depending on your car.

So, from there, look for a round or copper-like object that should be about a couple of inches long and has a wire that’s connected to the end of it.

From there, disconnect the wire from the sender and then start your engine. If the oil pressure light comes on or if the oil pressure gauge isn’t moving, that means that you have done a good job. You should now remove the sending unit using a wrench.

Step 2

Look for the double male-end compression fitting in the new mechanical oil pressure gauge kit. 

Step 3

When you’ve already found the compression fitting, slide a compression nut on the tube that should have a hole at the center.

Place this tube against the male end of the compression fitting of your new mechanical oil pressure gauge.

Push the nut into the fitting while you are maintaining pressure on the tube and then tighten the nut with a wrench.

Step 4

Route the tube carefully into the passenger compartment. You should be able to find a firewall where wires run through as this firewall is supposed to be the rear end of your engine compartment.

Slide the tubing through that hole and then choose a spot on the firewall wherein you can drill a hole. Use a grommet around the protect the tube.

Step 5

Find a place where you can mount your oil pressure gauge or just simply use the place of your old gauge.

It should be able to attach or mount onto your dashboard using two screws. Y

ou can use a spot along the bottom end of the dashboard.

Step 6

After that, you can now route the oil tube to the gauge. Cut off any excess tube so that the tube will just be the right length.

From there, slide a compression nut over to the end of the tube and then follow it up with a ferrule.

Now, push the tube against the compression fitting behind the gauge and then allow the nut and ferrule to thread through.

Tighten them with a wrench.

Make sure that you are holding the compression fitting on the gauge with a wrench so that the gauge will not spin.

Step 7

Finally, remove the nuts and washers found on the bracket attached to the rear part of your new gauge.

Mount the gauge in the desired spot and then use the washers and nuts to hold it in place.

Try starting your engine to see if the mechanical oil pressure is now working.

Here is an excellent video on how to install a mechanical oil pressure gauge.

Do you have to bleed a mechanical oil pressure gauge?

While the air may slightly affect your mechanical oil pressure gauge, you don’t need to bleed the mechanical oil pressure gauge.

That’s because, as far as the gauge is concerned, air and oil pressure are just similar.

But, to be on the safe side, you may want to bleed your mechanical oil pressure gauge so that you can have a more accurate reading that won’t be affected by whatever air is left in the tube that you just installed.


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