Oil pressure light when idle?

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gdizzle

gdizzle

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Ok you guys gotta know what this means. 66 dart, 225ci, 270.
had the engine rebuilt 8 months ago.

probably have put about 500 miles on it since then.

So this red oil light at the left of the dash (stock) normally is lit when I start the engine, then it goes off and stays off.

Yesterday, warm day, I am driving around town and the oil light lit up any time I stopped accelerating, and at idle. But if I step on the pedal the light immediately goes off, I get off the pedal, light immediately goes on?

Then today, I check oil, full. and clean. I replaced the oil about 4 weeks ago.
I start it up, light stays on until I rev a little, then off, then idle back on, then rev off. So I press pedal down and rev for about 10 seconds. Now the light stays off when I let off the pedal? I drove it around town and the light stayed off???

What could possible be going on here?

thanks for any help.

I did think about possible loose connection at the pressure plug, but it seems to be on.
 
Go buy a mechanical oil pressure gauge. It can be temporarily installed if you want. It will tell you what your issue is.
 
furyus2 said:
Go buy a mechanical oil pressure gauge. It can be temporarily installed if you want. It will tell you what your issue is.
Click to expand...

If you are in the lower range of comfortable pressure readings then I would get thicker oil or bump the idle a little.
 
I am using 30w for high mileage engines.

Also the oil pressure switch was replaced when I had the engine rebuilt.

Does anyone have more inifo on how to install a mechanical oil pressure gauge?
Do they make them to just replace my current screw in switch?

I already have a gas gauge and temperature gauge hangin from the dash. not sure where a 3rd gauge would fit.

any help is appreciated.

also I do know they put in a new oil pump when they rebuilt engine.
 
The oil pressure gauge install kit will have a fitting to screw in where the switch is now. If you want both you can also get a "T" fitting to do that. Get a 3 gauge bracket to go where the two are now....
 
When you had the engine rebuilt did you have a new oil pump put on if not try removing the oil pressure relief valve and clean the spring and plunger. My 73 started doing the same thing and after I cleaned it I haven't had any problems since.
 
How does someone not know what it means when the oil light comes on? It means you have lost or are low on oil pressure. Easily verified with a manual gauge.
 
Sometimes it's as simple as an idle adjustment. If it's dropping to low at the point of return the light can come on.
 
A loose connection will cause the light to never come on, so that is not the issue.

A good /6 won't let the light some on at even a very low idle. The switch should come on and light the oil light at 8 psi or less. With a good pump, this should not happen unless the bearings are too loose. So it is either loose bearings, a loose pump, a pressure relief valve not seating as mentioned, a bad switch, or a bad/plugged oil filter. Put on the oil pressure gauge as suggested. Also, speak to the builder and ask:
- Did they install a new oil pump?
- Did they turn the crank? What did they set the bearing clearances to, for both mains and rods?
- Have you changed the oil and filter since it was rebuilt?
 
Try a different brand of oil filter. Hasn't happened to me, but several slanters have had a problem with low oil pressure, when using Fram filters.
 
If you haven't changed the oil since the overhaul, you need to. Metal bits get into the oil from the rings seating, cam breaking in and whatever grit might be in the oil passages. Use dino oil until you have enough miles to ensure it's broken in. Good filter..WIX, Purolator, Hastings etc. No junk like Fram.
 
Possibly:
- low oil level; add half a quart of oil and see if things improve
- sludge in the oil pan being sucked up when the engine revs up; you'll only get that out by removing the pan; looking inside the valve cover to see if there is sludge in the head area would be an easy first step to determine if this is a likely issue
- bad or plugged oil filter blocking flow; replace with a WIX oil filter and see if that helps
- bare oil pressure sender wire moving against the block or other metal surface and grounding the wire and lighting the light
 
nm9stheham said:
Possibly:
- low oil level; add half a quart of oil and see if things improve
- sludge in the oil pan being sucked up when the engine revs up; you'll only get that out by removing the pan; looking inside the valve cover to see if there is sludge in the head area would be an easy first step to determine if this is a likely issue
- bad or plugged oil filter blocking flow; replace with a WIX oil filter and see if that helps
- bare oil pressure sender wire moving against the block or other metal surface and grounding the wire and lighting the light
Click to expand...
Ill check all these thank you HAM, Very helpful tips!
 
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