Oil Pressure - HELP

[1969mustang302 10]

Hey guys, took my Mustang out the other day and noticed the oil pressure was reading low. At first it was only when I was idling but then as I started to drive it would go up a little bit but as I drove more and more it continued to stay on the low side. I figured it was because I had not yet changed to thicker oil for hot summer so I did that today. Still reads low pressure...anybody have a similar issue or know what I can do to diagnose the problem?

 

Thanks

[blueblood 26]

I would start by getting a workshop to check the pressure with a pressure gauge.

May just be a faulty sender.

[fvike 173]

I have that exact problem on my DD '89 Mercedes-Benz 300SE. And it has a knocking rod. I've changed the bearings several times, and the rod bolts the last time I did it. Got a bit more oil pressure then, but it's still a bit low. There's no way around it, that engine need to be rebuilt. And I think you may have the same problem. If the oil pressure drops when the engine gets hot, that is a pretty good sign that you have a bad bearing. Thinner (hot) oil bleed more with a bad bearing. Probably not what you want to hear, but that is my experience.

[sportsroof69 13]

Buy a cheap mechanical gauge, and see what the pressure is doing. Without some real numbers from a more reliable gauge, it's hard to tell anything.

[danno 128]

The same thing happened to me. Mine was low all the time, even when cold, and it turned out to be my oil pump was going bad. While I was diagnosing it, it failed completely. The oil pump locked up when the car was shut off, and it locked up so much the starter could not spin the motor. When she goes, she goes quick. I don't know of any way to check the oil pump to see if it is working. Maybe pull off a valve cover, and if it is working you should see oil to the rockers when trying to start the motor.

 

If your car has a lot of miles, maybe plan on just replacing it? It is a time consuming process to pull the oil pan, but maybe it is time to do it?

[LoneWolf2U 136]

Buy a cheap mechanical gauge, and see what the pressure is doing. Without some real numbers from a more reliable gauge, it's hard to tell anything.

 

+1, Verify the problems first with live feed guage.

It could just be bad/weak sending unit or passage sludge giving a false reading.

[ashleesmach1 28]

install a mech oil gauge but first check the wire going to the original setup. check it all the way back to the firewall. I had a similar problem and it was the wire

[fredfordguy 16]

What is the oil pressure in LBS???? That's gotta be your first step

[Pizzeck 10]

Does anyone have a source for an inexpensive (mechanical) gauge that can be temporarily connected to check oil pressure?

[Pakrat 1,043]

You should be able to get a cheap one like Sunpro for $15 or so at any Autozone or parts store.

 

+4 on this suggestion, best and cheapest next step to see if their really is a problem with the pressure first. I had a simillar issue and kept the gauge mounted under my dash on a sping hinge so I could check it when I wanted to and keep it out of sight when I didn't, just changed from the plastic line to a more permanent copper one. In the rebuild I have descided to add it and several other good info gauges in the engine bay where the windshield washer bottle was, handy to have at a glance when working on the engine.

Edited May 7, 2013 by Pakrat