How to install an Oil pressure gauge on a John Deere (X3xx X5xx) air cooled engine

Many of us like to have gauges to monitor the engine, so here is how to install an oil pressure gauge on an X3xx and X5xx air cooled engine.

Here is a typical oil pressure kit with the hardware usually provide with it.
For this project you need an 1, 1/2 inch (40mm) gauge that you could get at any auto part store or on the web.





First you have to take off the steering wheel; I used an air hammer with a flat head punch.



Here's how to remove the steering wheel.

Unscrew the nut, put your knees under the steering wheel and apply a tension to raise it and put the air hammer on the top of the center shaft and give it a few shot gently.

If you don't have a air hammer do not try with a regular hammer, you will damage the shaft. Ask your mechanic to do it for you.

Note: I do not recommend a puller you will damage the steering wheel and no hole are provided to install the puller.



In the back of the hours meter panel you'll find the electronic control module for the engine.

You have to remove the module (two screws) to gain access to the 5 retainer clips that hold the hours meter panel.



Be gentle and raise carefully the panel like in the picture.





Note: Don't forget to disconnect the hour meter.



You need a 1, 1/2 inch (40mm) gauge to fit the space under the hour's meter.

Note: Make sure you find the center before making the hole.
Note: It's possible to install two gauges side by side like a voltmeter.
Note: In this picture the hole is not in the center correctly.

In the dash you will see a brace in the middle holding both side (in the yellow box), cut the center piece where the red line is.
The brace is not use for this model of tractor.





Now we need to connect the gauge light, you have to find a yellow wire coming from the ignition switch.

Check with a test light before, it has several yellow wires in there.



Find a good metal surface and install the ground wire.



Now turn the ignition switch to test light operation.





Now we go for the installation of the coupling of the nylon tube on the engine. Right on top of the oil filter you'll find a bolt, remove it to connect the plumbing fitting.

I install a 3 inch pipe extension with a 90 degree elbow for easier access.

Note: The thread in the engine block are 1/8 NPT (National Pipe thread) standard plumbing thread.
Note: Use Teflon sealer liquid or tape.





Install the nylon tube far from any heat source and used Zip Tie to secure it, has show in the picture.



Cut the remaining nylon tube to the proper length.

Connect the tube to the gauge with the fitting provided in the oil pressure gauge kit.

Note: It's not mandatory to purge the oil circuit. (bleeding the air out of the line).

Follow the procedure backward to reassemble the dash.

Note: Don't over tighten the steering wheel.
Note: Make sure everything is secure before starting the engine.

Start the engine, let it run for 10 minute, make sure nothing leak.





When the engine will heat up the pressure will drop, this phenomena is normal.

The normal pressure will be reach when the engine will get to the normal running temperature.

Now enjoy your final result.



Originally posted on MyTractorForum.com November 2010.