# Mechanical oil pressure gauge jumping / Volts Issue



## tags68 (Oct 6, 2010)

Hey Guys,
Finally got my 1968 lemans back from the resto shop, and having some issues. 
1st, my mechanical oil pressure gauge is jumping. It didn’t do this before, but they replaced the oil pump when they painted the engine. See below for a video of what im seeing. Would this be normal for a new pump? The gauge is only a year old, so id hope the gauge isn’t bad.






Also, Still having an issue with too many volts, 15-16 volts. Tried several regulators and alternators, and still having exact same results. Guy at the shop even tried to adjust the regulators internals, and still same issue. Engine/body/chassis are all grounded in the front correctly from what I can tell. Has anyone hear of this issue and had it be something besides reg/alt/battery (all been replaced)? 

Thanks,
Mike


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## likethat (Oct 5, 2007)

Is that 16 volts with the gauge and/or with a voltmeter just not the gauge? I have seen oil gauges jump around. Have you tried bleeding the line at the back of the gauge to make sure there is no air in the line?


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## Eric Animal (Oct 28, 2007)

:agree that Oil gauge wouldn't make me happy......check your volt gauge against another one....gauge may be inaccurate...Eric


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## tags68 (Oct 6, 2010)

Im getting 16 on both the volt meter and a multimeter. I think ill have to start pulling fuses and see if any of the circuits might be the issue.
Might have a lead on the oil pressure issue, the braided steel tube going to the oil pres gauge seems to be stuck on top of the transmission somewhere. (went from st300 to th350). I wonder if its pinched somewhere and the vibrations of causing the guage shaking.


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## Eric Animal (Oct 28, 2007)

Could be pinched and vibrating,, check that...if not that swap the oil gauge out and see what happens......16V = overcharging...usually caused by a bad Voltage regulator AND it is NOT uncommon to get several bad parts in a row.........eric:willy:


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## Rukee (Feb 8, 2007)

Don't run it at 16v, I did and the battery blew up in my face!!! Sprayed the valve covers, air cleaner covers, inner fender wells, grills, as well as my face, wasn't pretty.


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## freethinker (Nov 14, 2009)

i think its the oil pressure gauge. most of them have a tiny hole on the inlet to dampen fluctuations. that gauge seems like its undampened.



tags68 said:


> Hey Guys,
> Finally got my 1968 lemans back from the resto shop, and having some issues.
> 1st, my mechanical oil pressure gauge is jumping. It didn’t do this before, but they replaced the oil pump when they painted the engine. See below for a video of what im seeing. Would this be normal for a new pump? The gauge is only a year old, so id hope the gauge isn’t bad.
> 
> ...


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## tags68 (Oct 6, 2010)

Well it look like the volts issue WAS a bad regulator!!!! I kept reading about the Wells VR715 solid state regulator in the chevy forums, so figure i would give it a try.
Picked it up at autozone, and so far, only ran for a few minutes , its between 14 -15 volts. Ill have to grab my buddies multimeter tomorow and confirm the #'s .. but so far look like i finally found a functional regulator!!!!
thanks for all the help guys!!!!


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## Eric Animal (Oct 28, 2007)

This seems to be a GROWING PROBLEM in troubleshooting/diagnostics.....the "repeatedly bad part factor"....:willy:


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