Since my wife went over to the dark side(Ford Taurus), my 65 Barracuda is not dealing well with being parked most of the time. I only drive it occasionally now. The last few times I drove it the idiot light took an unusually long time to shut off when first started. It was due for an oil change so I drove it a few miles yesterday and this time the light went out normally when I started it and I did not notice anything unusual when I drove it. The engine has somewhere around 150,000 miles on it but is still fairly tight. Ya gotta love these slants for longevity if nothing else.

I changed oil when I got home. I started the car during the oil change to fill the filter and the idiot light did not go off at all. I let it run quite a bit longer than it normally takes to fill the filter and no joy. I did not hear any bearing noise or unusual lifter noise so it sounded like it was getting oil. I then removed the new filter and it was full so the pump is working. I put a different filter on it just in case and it made no difference.

At that point I decided to adjourn for further reflection and drove the car into the back yard. When I put the auto trans in gear the light went out for a second and then came back on. The light would flicker at times if I revved the engine. Still no bearing noise or any indication it is not getting oil.

It could be a stuck relief valve but I suspect it is an electrical problem since the light went out when I put it in gear and the RPMs dropped and presumably the voltage dropped. How does the sender work? I assume it grounds the light circuit when the oil pressure is to low and breaks the ground when the pressure comes up? It is strange that it would fail during the oil change, but that could be coincidence. I run 10W-30 oil.

Is there any way to test the sender? I suppose the instrument panel voltage regulator could be dying too as I have had some strange gauge readings from time to time recently. Does the idiot light circuit use the regulated voltage or 12 volts?

Any hints as to how to troubleshoot this?

The car really doesn't like being parked for weeks at a time. The trans is acting up too.

No the light works on its own with stright voltage and not threw the regulator. The wire that runs to the oil sender could be grounding out some where, which is why when you put it in gear it went out (it ungrounded) . Also I have seen some trash or gunk get in the little passage that feeds the sender. Best thing would be to go buy a new sender anyway( there cheap $6.00 to $12.00) , check the wiring wial you are replacing it. And when you take the old sender out, start the motor briefly so it squirts oil out of the whole the sender goes in to clear any trash that may be building up.

If you do wish to check the sender take a test light and hook its lead to the Possitive side of the battery, Strick the piont of the test light to ground to make sure it lights when it gets a ground. Then hook the piont of the test lead to the sender prong and start the engine. If the sender is working it will light the test light when you touch the Prong on the sender, then when the engine starts it will go out when the engine gets oil pressure. This simulates exactly the same cuircut that the car has when you test it this way.

Jess

It is possible you really have an oil pressure problem. The light will come on when the pressure is about 5-7 LBS. At idle the pressure might be just at that point, and when putting in gear, the rpm drops just enough to lower the pressure to the point of lighting the light. If it were me I would buy a cheap oil pressure gauge, remove the stock sender, install the gauge (don't have to put it inside the car), start the engine and see what the pressure really is.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Thanks for the info. I won't be able to look at it for awhile. My wife's younger sister died unexpectedly and we will be traveling this week.