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Whilst poking around behind the dash of my '54 GMC I noticed that the oil pressure gauge which doesn't work, doesn't work for a good reason...there are no wires hooked up to it. Therefore, I went looking or the other end of the oil pressure gauge system and tried to locate the oil pressure sender but it appears to be MIA. Question...where is the sender supposed to be installed on the engine, (there appears to be two possible locations, one up front on the left side and the other far back on the left side). Also, anyone know where I can get the correct sending unit fo the gauge? (engine in a 248). Thanks!

54 GMC:

To the best of my knowledge :rolleyes: , all of these sixes had MECHANICAL oil pressure gauges up into the '70s.

There should be a brass block on the back side of the gauge that's tapped and threaded for a small fitting nut, and a tiny steel or copper tube that runs through the firewall and connects to the engine, on the left side for a Chevy, on the ... right (?) for GMC (?).

I think the only engines that had an electrical type sender were the ones with idiot lights.

Frank54,

I'll have to look again, but I could swear that the gauge had two electrical posts sticking out of the back. Now, you've got me curious and I probably won't get a chance to look until my next day off, (Monday). :confused:

Hey 54GMC, Mick Inniss here, my stock 54 GMC has a mechanical oil tube hooked into driver side of motor!!! This is the round 2 3/4 oil pressure gauge!!! Right? If you dont have an original gauge good luck finding one. It took me forever. But hey my OLD GIRL is worth it.

I just poked around through my box of 54 GMC gauges, they are all mechanical. If you need an orig. gauge email me.

Hey, you guys were right!...(like I should ever doubt it). I pulled the dash and took a closer look and, by gosh, the oil gauge is mechanical! There are a couple screws on the back of the gauge I took for electricial terminals when I took a quick look at it the other day...(better get the old eyes checked again). So, now that I've figured out this highly technical aspect of my truck the next question is, what do I need to run an oil line to the gauge? What type of fittings and tubing should I use? Suggestions from the wiser (wiser then I, that is) stovebolters would be welcome. Thanks!

54gmc you should be able to get an "oil line" kit for you gauge. Most of these are with the plastic tubing but you can still get them with the copper line. However it typically is an on the hook item you may have to order it. Or by the "platic" kit and then go to the local plumbing supply shop and get some (3/16 I think) copper tubing. Match the OD of the plastic to the right siz copper. The fitting should be "universal". Then just connect the to gauge and the left rear side of the motor. If you have an external oil filter there should be a line coming from the engine to the filter. At the block there should be a "T" that you can connect too. Hope this helps.

54GMC,

If you go with the plastic line, just make sure that you have it secured AWAY from any hot exhaust parts!

Previous owner was not so careful on my '61 Willys, and one night I noticed that all of a sudden, I had no oil pressure and smelled burning oil!

I've done that too. Luckily it sprayed on the manifold and I noticed. Good thing I carry vise grips.

I had a problem with the plastic line on my 53 GMC I had in highschool.I was taking a spare tire to my friends dad at 5a.m. I could not figure out why the fog seemed so thick behind the truck that morning.I took the tire tohis dad and on the way(15miles one way),I stepped on the brakes,testing them before we went down the other side of the mountain which had 15mph corners and switchbacks on the way to the bottom.No brakes,pedal to the floor!!

jammed it into second and shut the engine off as we pulled to the side of the road.Walked about 100yds and got a ride from a logging crummy.Well we finally delivered the tire and stopped on the way to pick up my 53. His dad told me to drive it back and use 2nd geargoing down hill.I drove it 10 miles back to their house,two long steep down-grades on the way,2nd gear all the way down.I checked the oil in the truck and there was not a drop on the stick!!
I put 5quarts in to bring it back to the full mark and started the truck.The leak(and cause of the excess FOG was apparent as the oil pressure line was squirting directly onto the header pipe just under the front of the cab.I fixed the line and replaced the clevis pit that had fallen out of the brake linkage and drove the truck for two mre years,not one problem with the engine,before I traded it to a friend who used it for a year and a half before parting it out!

GMC=tough truck!