Oil pressure problems, maybe.

Posted by Bob E. On 2016/7/17 16:35:45

Here is the story. I was driving my stock '55 Patrician up to a body shop to get my hood re-installed (long story for another post). The shop is about 18 miles away and it took me ~35 minutes each way. I made this same round trip a couple of weeks ago with no problems at all. This time i made it there without incident although while there there was a puddle of antifreeze under the car when we were done, maybe a cup or less of liquid. Drove home and after about 5 minutes, i felt the car 'surging' or 'straining' while driving at a constant speed and flat terrain. I started thinking the fuel pump was giving out or my fuel gauge was lying to me so I slowed down and started looking for a place to pull over. I looked at the gauges and Temp was a bit higher than normal (it was halfway between middle and Hot) but oil pressure was decreasing. Oil pressure got to "L" and I pulled into a gas station to see what was up. I turned the engine off and checked the oil level which was about a 1/2" above Full (normal for me). There was some oil smoke (light) coming out of oil breather cap and the dipstick hole when I removed dipstick. These are normal for my car. (Note I did a compression check and cylinder leak test with great results weeks ago and that data is in a previous post)

After a few minutes, I turned the car back on and Oil press rose to the usual middle position as if all was good. So I pulled it to the pumps and filled the tank (just in case there was also fuel sender issue). When I restarted, the oil Press started to rise, got to about 1/4 position but then started decreasing back to L. Shut it off again then started it a minute later and oil press came up as normal to the middle position. Figuring that this could be the sender unit, I decided to go for home and I made it without any problems at all (while staring at the gauges the whole time!). The car still seemed to struggle going over overpasses but Oil press stayed solid dead center in the middle and Temp was 3/4 to H. Radiator fluid was down about an inch from when I started the day but still above the level of the core.


I replaced the oil pressure sender just a couple of months ago with an Echlin OP6091 from NAPA as the old one didnt give any reading at all.

So the question, what's up? Could this new sender unit be flaky, could the pump itself be on it's last legs? It seems unlikely to go from no problems to multiple at the same time (oil sender/pump issue plus a transmission or fuel pump issue causing the strain... etc)?

BTW: I do have a Jack Vines Oil pump replacement kit in hand and have been waiting for to get my hood back so I can do that replacement. Probably not relevant but I do not have a working generator installed so I rely on battery strength to get there, charge it while I'm there and then make it home. It was at 12.6V when I arrived back home.

I'm also wondering if I should "tee" off the oil pressure sender port and run an independent set of a real sensor and gauges with numbers to keep the worry factor down. Anyone done that in a somewhat elegant way?

I appreciate any advice you can provide as I want to get this to be a reliable driver.

thank you,
Bob