LOW oil pressure !!!! help!!!

[eldawg4100]

this is the second or 3rd time its happened.. after draning my oil for 15-20 minutes, draining the filter (it does not have lots of miles on it) and re-filling, i started the car, and got bad knocks, and the compute read LOW OIL PRESSURE STOP ENGINE... i just let it run for about 10-15 seconds and it was like, at once it just stopped and ran smooth.... this sounds real bad, its getting worse and worse everytime i change my oil... oil is mobil 1 tri-syn 0w-40 and the filter is a penske (its happened before with a supertech and others)

now that i think about it, even before the warnings, when i changed my oil months ago it would just knock for a few seconds.. now it shows a message, i am fearful for what this knocking and low oil pressure caused... it ONLY happens right after i change my oil, does not even happen if i let the car sit for 3 days outside in the cold!


any ideas on why this is happening?

 

[westex39]

Your oil pump maybe losing it's prime due to the oil draining out of it. How long do you let the oil drain before refilling?
I usually let mine drain for 30 minutes or more and have never had a problem. I do prefill my oil filter prior to installation. My filter is situated vertically. If your filter is not vertical put in as much oil as possible prior to installing.
I too would be worried if my engine knocked on initial startup.
Hope you haven't damaged it.

regards,

westex

[ February 21, 2003, 08:50 AM: Message edited by: westex39 ]

 

[Mike_dup1]

quote:

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Technical Service Bulletin 93-1
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Oil Pump Prime
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Immediately after an oil change, one of the most confusing issues to face the typical do-it-yourselfer or professional mechanic is lack of oil pressure on engine start-up.

Although not a common occurrence, it is very possible that the oil pump may lose its prime during the oil change.

When the used motor oil is drained from the engine, the oil may also drain from the oil pump pickup tube and possibly from the oil pump itself. When new motor oil is added, the pump's pickup tube inlet again becomes submerged, trapping air in the tube on the suction side of the oil pump. The trapped air will cause cavitation of the pump and prevent it from producing oil flow and subsequent oil pressure. The low oil pressure light will remain on or the oil pressure gauge will register little or no pressure when the engine is started.

Many installers tend to blame this on the oil filter and assume that the filter is blocking the flow of oil. Since the filter is now suspect, the installer will install a second filter. Sometimes this solves the problem because the trapped air was released when the first filter was removed. Of course, the installer's suspicion that the filter was at fault has increased.

The point is, the oil filter was not the problem and, in most cases, there is a simple solution.

If the low oil pressure light remains on or the oil pressure gauge reads little or no pressure within 30 seconds of engine start-up, stop the engine. Loosen the oil filter until the sealing gasket barely touches the filter mounting base. Disable the ignition system so the engine will not start. Turn the engine over with the starter until oil appears at the sealing gasket. DO NOT CRANK THE ENGINE FOR MORE THAN 30 SECONDS. After oil appears at the gasket, tighten the filter and wipe off the excess oil. Start the engine. Oil pressure should return to normal within ten seconds.

If the above procedure fails, it may be necessary to remove the filter and use an oil squirt can, with clean motor oil, to squirt oil into the oil filter's mounting base inlet hole, which is adjacent to the threaded mounting stud. This will prime the pump.

Next, fill the filter with oil, reinstall and tighten. Oil pressure should return to normal within ten seconds after starting the engine.

Replacing the oil in the crankcase immediately after draining will prevent the oil pump from losing it's prime.

Also, make sure the spin-on oil filter is installed correctly. Printed installation instructions will be found either on the filter itself or on the filter box.

For additional information, contact:

Filter Manufacturers Council
P.O. Box 13966
Research Triangle Park, NC 27709-3966
Phone: 919/549-4800 Fax: 919/549-4824
Used Filter Recycling Hotline: 800/993-4583
filtercouncil

Administered by Motor & Equipment Manufacturers Association

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[ February 21, 2003, 01:08 PM: Message edited by: ED P. ]

 

[ALJAMES]

Hi ELDAWG,

I have a 92 Deville and have had a similar problem in the past. The oil pump is looseing its prime due to the length of time you are allowing the oil to drain. Here is how I solved my problem. Change the oil filter first and fill it to about half full. This is about the maximum amount that can be added due to the angle it is mounted. Then drain the oil and immediately replace the drain plug when the stream is about 1/16 inch in diameter. Immediately start filling the crankcase with the replacement oil. Start the car as soon as possible and let it run for a few minutes while checking for leaks. Shut it off and wait 10 minutes, check and top off the oil.

By the way, I have found the best oil filter to stop rod knock on startup to be an STP. I also use Formula Shell 20w50 in this 4.9 engine.

 

[7TFord]

I've dumped a lot of oil over the years and have never had an incident like yours. I may have a slight top end rattle for maybe 2 seconds maximum when first starting the motor in my V6 Toyota after an oil change. It has a 4 cam valve train though which takes a lot of oil. You are having this noise for 15 seconds? Are we talking a new vehicle here? You say this is the second or third time it has happened. What if any changes in oil/filter have been made at the time that this started happening? Is there any chance that you have a mechanical problem in your engine? I let my vehicle drain until it quits dripping. I'm not sure how long that is but must be at least 20 minutes. Just a point of interest. I just finished draining the oil out of my classic 70 Mustang and left it too drip overnight. I put in the oil this AM and fired it up and had no noise at all and immediate oil pressure.

I presume that the newer vehicles have a different drive system for the oil pumps compared to the distributor driven pump of my old Mustang, and you would think a more efficient one. The oil pump on my Toyota truck is driven from the end of the crankshaft which probably allows for quicker pressure. As stated, if you can fill your oil filter first it may help but the filter on my Tacoma is upside down so this is not an issue. The filters are usually small now and so we aren't talking a whole lot of oil here anyway. I can see you maybe loosing prime in your oil pump now and then but not to that extend on every oil change. I'd be vary nervous if my motor was running without oil pressure for more than a few seconds.

 

[dickwells]

Ok, so I am a fanatic on filling the filter before putting it on, but I wonder if this would work? Fill the filter until it will not take any more. Put a funnel in the oil fill hole. Hold the filter upside down over the funnel until the center cavity quickly drains and then quickly put it on the car. Might be a little messy but I bet it could be done. I note that it takes quite a while for the oil to soak through the paper to fill the outer cavity so it should take a while coming back, and the Anti backdrain valve would keep it inside the outer holes. Oh, never mind.

 

[MolaKule]

I usually know how much oil it takes to charge the filter so when I change oil, I add over the dipstick full mark to insure that that enough oil is there. Extra oil weighs more and will usually push out any air bubbles.

I would certainly be using an oil with a good barrier additive such as moly, since you don't have much oil pressure for 10-15 seconds. If the engine is not knocking or making sounds after the oil pressure comes up, your engine maybe ok.

Since this oil is trysyn, I would add 1/2 pint of 132 at each oil change.

 

[eldawg4100]

yea... STP is a good filter, luckily i dont have any startup issues when i dont change the oil! mine is a 92 seville, only 67k but somehow runs like 167k lol... great engine, has some bad designs though..

have you replaced the fuel injectors yet? if not, you will sometime lol, i had 2 go out already. cleaning them makes it worse. it strips the insulation around the windings then give the computer (in my case) 6 ohm loads instead of 17 ohms, and spiked the computer. what a headache!

 

[Greg]

quote:

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Originally posted by dickwells:
Ok, so I am a fanatic on filling the filter before putting it on, but I wonder if this would work? Fill the filter until it will not take any more. Put a funnel in the oil fill hole. Hold the filter upside down over the funnel until the center cavity quickly drains and then quickly put it on the car. Might be a little messy but I bet it could be done. I note that it takes quite a while for the oil to soak through the paper to fill the outer cavity so it should take a while coming back, and the Anti backdrain valve would keep it inside the outer holes. Oh, never mind.

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this would not work.

 

[OneQuartLow]

Dickwells, Position the upright filter next to the mount and pivot only enough to get the filter outlet over the mount threads. So long as you do this in one fluid motion the only leakage should be into the engine. I suppose it could be worse if there isn't room to rotate the filter.

My record so far is 22oz into a PurONE 30001 before 90* mounting. Didn't spill a drop, though you can bet I had a drain-pan below!

David