Occasional Oil Pressure Light for 2-3 seconds in my 318. Should I panic?

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ir3333 said:
This has turned into an oil pump pick up post.
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Sorry, not my intention to poke the bears or stir the pot. But it really is valuable for me to collect some solid knowledge and ideas before I dive in to see what's wrong. This thread has certainly provided that. Thanks all for the help, and I'll post an update once I have a chance to dive in.

Now, who wants to debate and do some chest-pounding about whether my stock Swinger can beat a Toyota Tercel in the quarter mile!
 
ir3333 said:
My oil light would come on intermittently...scary when it stayed on! I pulled over and the engine was idling smooth and not overheating so i just drove it home.
I screwed in a new sending unit and the oil light never came on again.
I'd try that first if i was you...10 minute job and a few bucks!
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Seriously THIS is the 1ST step.
Typical forum answers making you do the hardest thing first like pulling a pan or plumbing a gauge.
Just change the sender and see it it goes away.
If the engine isn't changing tone I bet it is this.
My sending unit with a Guage went bad randomly it did the same thing.
Could also be a loose wire.
Easy first then progressively harder.
 
G70464 said:
Seriously THIS is the 1ST step.
Typical forum answers making you do the hardest thing first like pulling a pan or plumbing a gauge.
Just change the sender and see it it goes away.
If the engine isn't changing tone I bet it is this.
My sending unit with a Guage went bad randomly it did the same thing.
Could also be a loose wire.
Easy first then progressively harder.
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Throwing parts at it is not diagnosis and teaches him nothing. The first best suggestion is to get a manual gauge on it. There are procedures for everything and verification of oil pressure.....or lack thereof should be the first thing he does.
 
G70464 said:
Seriously THIS is the 1ST step.
Typical forum answers making you do the hardest thing first like pulling a pan or plumbing a gauge.
Just change the sender and see it it goes away.
If the engine isn't changing tone I bet it is this.
My sending unit with a Guage went bad randomly it did the same thing.
Could also be a loose wire.
Easy first then progressively harder.
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I agree, as I've always said do the simple things first
 
With kids/job/daily-driving-need I kinda have to get dirty and do do everything I can in one shot. I just ordered a pressure gauge, I will probably check my oil pressure, replace the sender (no problem throwing a $10 part at something) and check that all the wiring is secure when I'm changing the oil. At the same time, I'll also do my best to look inside the pan with my bore scope and get as much of a look as as possible on the positioning and integrity of the pickup. Hopefully this will all either yield a solved problem or an idea of what else needs to be done.
 
Steven Vames said:
With kids/job/daily-driving-need I kinda have to get dirty and do do everything I can in one shot. I just ordered a pressure gauge, I will probably check my oil pressure, replace the sender (no problem throwing a $10 part at something) and check that all the wiring is secure when I'm changing the oil. At the same time, I'll also do my best to look inside the pan with my bore scope and get as much of a look as as possible on the positioning and integrity of the pickup. Hopefully this will all either yield a solved problem or an idea of what else needs to be done.
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Try to get a look at the bottom of the pan, too to see if there's sludge buildup.
 
BTW...

The sender GROUNDS to make the light go on. A loose wire would not turn the light on UNLESS it is contacting a ground or there is a bare spot on the wires insulation contacting ground.

The liklyhood of that exhibiting the symptoms as described are rare but posable.

Wire moving during breaking or turning contacting ground.
 
Its been about a year, but I finally got this fixed. I was procrastinating because I dreaded the idea of getting my car on jack stands, getting on the floor and pulling my oil pan, putting in a new pickup, and doing a good job of sealing the pan. So I finally bought a new pickup and pan seal and brought it to very competent local mechanic who took the the time to listen me spout all the wisdom I'd obtained from FABO.

He made sure the pickup is touching the pan on the bottom, he sealed it perfectly (not even a drip!). Today I took it hard around a bunch or corners and on-ramps. The problem is gone.

Many thanks, especially to @HSDemon, who identified the problem spot-on from the beginning.
 
G70464 said:
Just change the sender and see it it goes away.
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An idiot light is just that, a light for idiots. Just because the light doesn't go on doesn't mean that you don't have oiling issues. The thing could be running with 10 lbs of oil pressure all the time and the light wouldn't come on. If the system is sucking air somewhere it would show up with an unstable reading on the gauge or with declining oil pressure as rpms increase (the opposite of what should happen). This is CHEAP insurance for your new engine!
 
vames said:
I daily drive my 72 Swinger with a remanufactured 318 (probably has ~1500 miles on it at this point). I believe the reman motor was obtained through one of the big parts chains. The car starts/runs/pulls great. But every once in a while I get my oil light coming on for a couple seconds -- sometimes on a hard turn freeway entrance, sometimes going straight. I don't baby it, but I don't step on the thing too hard -- its a cool retro driver, not a performance car. I've been a good boy and have changed the oil and filter three times since the motor was put in, with zinc additive each time.

Facts and questions:

  • At my first oil change, I filled to the full line on the dipstick, and I was getting a frequent oil light. Ran it for less than a minute and put another quart in it and it mostly stopped. The old engine was fine at the full-line on the dipstick, so I'm not sure what changed.

  • It doesn't happen every time I drive, and it doesn't happen going down the freeway. It's mostly on the streets at < 40mph. Other than the hard-turn-freeway-entrance there is nothing obvious about the conditions when it does happen (its usually on flat road -- we don't have many hills around here). It's not getting more frequent or less frequent.

  • The pan is the original (I know because a PO must have long ago tried to jack up the car using the pan and it's slightly convex on the bottom). Is there a chance that the reman engine came with a pickup that doesn't go deep enough into the pan? Is it even a thing that there can be a "wrong pickup" or a "right pickup"? Could a marginally dented (but not leaking) pan cause problems like this?

  • Not sure on the age of the oil pressure sender -- could a bad one cause this?

  • Wix oil filter -- not sure of the # but it fits and clearly works. Running 10-40 dinosaur Penzoil. Long Beach CA (almost always below 100F and above 50F)

  • Not sure its relevant, but the guy who installed the motor accidentally sent the 90-degree oil filter adapter back with the core, so we just used the Mancini Racing plate and it all seems to work fine.
Or maybe this is all normal and I shouldn't freak out. Any ideas/comments/things to check from the community would be greatly appreciated.

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Why in the hell did you change the oil 3 times already? 1500 Miles, that's like 500 miles every change. Stop it. Every 3,000 miles is fine.
 
RustyRatRod said:
Nobody makes new pans. You'll have to find good used. Also, WHERE is your oil pressure sending unit? Is it in the side of the block or at the oil pump?
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RustyRatRod said:
Nobody makes new pans. You'll have to find good used. Also, WHERE is your oil pressure sending unit? Is it in the side of the block or at the oil pump?
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Plenty of new pans.
 
Dan Georgino said:
Why in the hell did you change the oil 3 times already? 1500 Miles, that's like 500 miles every change. Stop it. Every 3,000 miles is fine.
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No doubt. First thing i would do is put a manual gauge on it, with a brass T so you can see the gauge and the light. (many have suggested) Use that as a diagnostic tool and pay attention to when it acts up. What does the gauge read? If it light acts up and the gauge doesn't, it is probably a sender or circuit issue. If both act up, it could be a pick up or oil pump issue. I'm sure this has all been discussed before in this thread but I didn't take the time to read through 3 pages of suggestions. Sorry.
 
str12-340 said:
An idiot light is just that, a light for idiots. Just because the light doesn't go on doesn't mean that you don't have oiling issues. The thing could be running with 10 lbs of oil pressure all the time and the light wouldn't come on. If the system is sucking air somewhere it would show up with an unstable reading on the gauge or with declining oil pressure as rpms increase (the opposite of what should happen). This is CHEAP insurance for your new engine!
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I did temporarily plumb in a oil pressure gauge a year ago. What did it tell me? Exactly what the idiot light was telling me. When fully warm, it was showing a range of about 25-60 psi depending on the RPM (idiot light OFF). When I went around a corner it would dip to 0-15 for half a second (idiot light ON for a moment) before building back quickly above 25 (idiot light OFF). After that, I wasn't so worried, which is why it took me a while to fix it.

Dan Georgino said:
Why in the hell did you change the oil 3 times already? 1500 Miles, that's like 500 miles every change. Stop it. Every 3,000 miles is fine.
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Dan - sorry to to offend you by wasting $35 on oil for a fresh rebuild. There was the first batch of oil, then I changed at 500 and then 1500 -- maybe overkill, but I wanted to treat it nicely during the break in period. From now on its every 3000, sir.

RustyRatRod said:
Yes, but if you look back you will see I mistakenly thought the discussion was about a slant 6. No new pans for those.
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Dude I've learned so much from your posts over the years that I'd never fault you for a mistaking a /6 thread for a 318 thread. Either way, I didn't get a new pan -- just used the old one.
 
vames said:
I did temporarily plumb in a oil pressure gauge a year ago. What did it tell me? Exactly what the idiot light was telling me. When fully warm, it was showing a range of about 25-60 psi depending on the RPM (idiot light OFF). When I went around a corner it would dip to 0-15 for half a second (idiot light ON for a moment) before building back quickly above 25 (idiot light OFF). After that, I wasn't so worried, which is why it took me a while to fix it.


Dan - sorry to to offend you by wasting $35 on oil for a fresh rebuild. There was the first batch of oil, then I changed at 500 and then 1500 -- maybe overkill, but I wanted to treat it nicely during the break in period. From now on its every 3000, sir.


Dude I've learned so much from your posts over the years that I'd never fault you for a mistaking a /6 thread for a 318 thread. Either way, I didn't get a new pan -- just used the old one.
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Good. I saw where you resolved the issue. That's good. Is it still resolved?
 
RustyRatRod said:
Good. I saw where you resolved the issue. That's good. Is it still resolved?
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Still resolved. Filled with 5 quarts (just hits the top line on the dipstick). I did about an hour of mixed driving with a few hard curves today and didn't see the oil light come on except for the ordinary momentary time it's on after starting it cold.

The moral of the story: In the stock setup, the pickup has to touch the bottom of the pan. Otherwise, you may momentarily lose pressure when the oil sloshes around.

1702278950623.png
 
vames said:
Still resolved. Filled with 5 quarts (just hits the top line on the dipstick). I did about an hour of mixed driving with a few hard curves today and didn't see the oil light come on except for the ordinary momentary time it's on after starting it cold.

The moral of the story: In the stock setup, the pickup has to touch the bottom of the pan. Otherwise, you may momentarily lose pressure when the oil sloshes around.

View attachment 1716177091
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Yup and many will argue until they die that it's not so, but there it is in black and white.....and yellow. lol
 
Just an FYI about the confusion about the difference betwee 1/4" clearance and 1/4" interference.
Definition:
What is the difference between a clearance fit and an interference fit?


"Clearance fit: In this type shaft diameter is always less than hole diameter, enabling two parts to move when assembled. Interference Fit: In this type shaft diameter is always greater than hole. In this case there is always overlapping of matting parts. It is type of tight fit."
Translation: interference- it touches, clearance- it doesn't.
 
vames said:
I did temporarily plumb in a oil pressure gauge a year ago. What did it tell me? Exactly what the idiot light was telling me. When fully warm, it was showing a range of about 25-60 psi depending on the RPM (idiot light OFF). When I went around a corner it would dip to 0-15 for half a second (idiot light ON for a moment) before building back quickly above 25 (idiot light OFF). After that, I wasn't so worried, which is why it took me a while to fix it.


Dan - sorry to to offend you by wasting $35 on oil for a fresh rebuild. There was the first batch of oil, then I changed at 500 and then 1500 -- maybe overkill, but I wanted to treat it nicely during the break in period. From now on its every 3000, sir.


Dude I've learned so much from your posts over the years that I'd never fault you for a mistaking a /6 thread for a 318 thread. Either way, I didn't get a new pan -- just used the old one.
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You said you changed it 3 times, now you say 2 times. Yes, you have the break-in oil for the first 500, then change again, so you are fine.
 
OK -- all good guys -- let's not bury the answer. I just wanted to update that I finally fixed this with help from Team FABO. Anybody searching this problem in the forums should know that the stock pickup has to touch the bottom of the stock pan for it to work right.

Also -- it's nice to not be timidly crawling out of corners scared that the pressure would drop. Now I'm confidently accelerating out of corners with all that stock 2bbl 318 power (lol)!
 
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