faulty oil pressure gauge?

[boys4545]

Just bought 1971 M35A2 w/ winch this week with broken oil pressure gauge (Indicator goes way over max). Engine on and off. I replaced it with one I bought off E-bay. The same thing happened. Goes way to over max. The guage is Faria Corp. There is plenty of oil in the engine. Does it just need an oil change? Have you seen this before? Is there a quick fix ? The engine sounds great! Does not stutter or seem to have any problems at all. I am a real newbie however. Can You guys point me in the right direction

 

[fuzzytoaster]

If you want to be sure of your oil pressure get a mechanical gauge off fleabay and test it. But check for a bad ground first.

 

[KsM715]

Could be a faulty sender or as fuzzy said, something in the wiring is causing it.

 

[doghead]

Troubleshooting the gauges is covered in the troubleshooting section of the -20 TM.

 

[Big Z]

TM -20-2-1 Pg 25-243. I also need to do a check.

 

[gimpyrobb]

There are 2 different sending units. Maybe your using the wrong combination of gauge and sending unit.

 

[whatadeuce]

Where is the sending unit located? and for the referenced tm. is TM-20-2-1 a complete number?

 

[steelandcanvas]

Here is a link to the TM and the complete number: http://test.steelsoldiers.com/upload/M35/TM9-2320-209-20-2-1.pdf
9-2320-209-20-2-1

 

[whatadeuce]

Thank You

 

[lawdog1623]

This happened to me in a newly acquired truck. Temp and oil gauge wouldnt work. The gauges werent grounding properly. I would start with the ground first. With the truck running or the accessory on, Take the gauge out of the panel, touch the rear of the gauge to the retainer clip that the cluster panel attaches to. If all other gauges work and it miraculously starts working you're having a ground issue somewhere. If it still doesnt work, get the CORRECT sending unit and replace it along with the gauge.

 

[dutchguy]

Just bought 1971 M35A2 w/ winch this week with broken oil pressure gauge (Indicator goes way over max). Engine on and off. I replaced it with one I bought off E-bay. The same thing happened. Goes way to over max. The guage is Faria Corp. There is plenty of oil in the engine. Does it just need an oil change? Have you seen this before? Is there a quick fix ? The engine sounds great! Does not stutter or seem to have any problems at all. I am a real newbie however. Can You guys point me in the right direction

FYI, "the correct sending unit / gauge combination" refers to the availability of both 0-60 and 0-120 psi gauges and sending units. I don't know if that was clear. I believe that you mentioned your problem was present both with the engine running, and not running. Sounds like a ground problem.

 

[recon]

Just went through this problem. Put new oil gauge in last May and it worked fine until 2 weeks ago. Gauge became erratic and would pin at high end. Checked ground but it became erratic again. Put in new sending unit. No change. Problem was wire connecting gauge and sending unit. Replaced wire and it solved the problem.

recon
Dutchess county, NY

 

[whatadeuce]

Its interesting to see how thesenproblems are worked out...