I need a little help here...

Last Friday on the way home from work I stopped at the store to pick something up. By this time the car had been driven about 30 miles non-stop. When I started the car up after leaving the store the Oil Pressure warning light came on and would not go out. I drove home about a mile and parked before the impending monster snow that we got here in Maryland. Before it all hit I checked the level and I was a quart low, so I wasn't really concerned.

After finally digging out on Sunday, I moved the car and the light did not come on. what?

Yesterday, my wife and I went out to do some errands and to keep from going crazy after being stuck inside for three days. The whole trip probably was about 5 miles. On the first leg we stopped at I kept the engine running while my wife went in to do her errand. The light was still off. After awhile I shut it off because it was getting very hot inside. Once I started it up again the light came back on and would not go off.

I'm going to check the light again today and my guess will be that it will be off and stay off as long as I don't turn the car off.

So my question is what is going on? Is it my oil pump? or like in Art's one post just a seal that has broken down inside the sump? Also, is the car safe to drive or should I park it and fix it ASAP? Please any and all help/advice on this is needed and welcome as I currently have one of my three vehicles out of commission and really can't afford to have two out, especially if the second one dies a horrible death due to lack of oil to the engine.

Thanks to all and I look forward to your responses.

Matt Bensing

Hi Matt,

Here's what I would do: If the only symptom is the light, and there's no clickety-click racket or other ominous sounds, I'd suspect the oil pressure sender or its wiring. The wiring is not the prime suspect it would have been in 81-87 years, but worth considering. Next time the light came on, I'd get a rag, (maybe some safety glasses) and carefully remove the oil filler cap while idling, and welcome any oil shower I might receive.

Next move would be to connect a gauge to the oil sender port, but on your B230 that's easy for me to say, but not convenient for most of us. The threads are metric there. Maybe I'd just swap in a new sender since they are cheap. While down there, I'd take a look at the black wire to see if it was getting into trouble further into the loom under the crank pulley.

When the seal goes, or the oil pump gets worn, the light comes on at lowest rpm, but goes out when you give it some gas. Steady on, without regard for rpm, is more often a symptom of a faulty warning light.
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Art Benstein near Baltimore

A lot of money is tainted. 'Taint yours and 'taint mine.

Art,

Thanks for responding! I've read a lot of your posts over the years and now I've finally gotten to meet you! Very Cool!

Ok, so now I know where the oil sender is located, as I've seen it on the brickboard today. How do I go about testing it? I've read the FAQ section, but am still unsure as to what I should be doing? When you say connect a gauge, I'm assuming a volt meter to check the resistance. If this is correct, what is the value that I should be looking at to determine if this is the culprit and therefore bad?

I will also check the wiring and see if I get an oil bath once I dig the car out either tomorrow or Friday.

Thanks again and I look forward to your response.

Matt

Hey Matt,

You're snowed in too. The gauge I'm talking about is a mechanical oil pressure gauge used for diagnosis. You'd want to do this procedure if you check out the electrics and are unsure about oil getting up to the cam. I'm hoping you have to go that far. First, try to see if the light is related to idle speed. That's your biggest clue.
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Art Benstein near Baltimore

"There's nothing like a home opener, whether it's at home or on the road."

Hey Art,

I finally got dug out today, but still can't get out of my street. Once I did that I was able to take look at the brick.

I checked the wire as best I could going to the sender unit and all looked fine. The wire and connection is some what oily, but then again the car does have 298000 miles on it. I disconnected it and started the car up and no light appeared on the instrument cluster as expected. I turned the car off, re-attached the wire and started the car back up. The light was still off.

I then let the car get warm. While it was getting warm, I listened to the engine and it sounded normal, no clickety clack from the valve cover and such. I even opened up the oil fill. I did get some oil coming out but not necessarily what I would expect, no bath if that's what your after, but I could put my palm over the cover and spots of oil did show up there, but definitely not a bath. I could see oil inside oil fill opening, so maybe its fine. It definitely was not dry if that is what your asking.

Once the car was warm I shut it off and re-started it. The light immediately came on and most likely will not go off until the car cools down.

So what do you think? Could it be a bad sender unit or something more ominous? The light once on does not flicker off when the accelerator is pressed, it stays on solid.

Let me know when you get a chance. I'm scheduled to have it looked at by my mechanic on Monday, so if you think I can hold off till then let me know.

Thanks in advance,

Matt

Matt, I think your car is OK. "Bath" was a bit of an exaggeration. It should be more like a spritz at idle, little drops getting kicked out so if you put your face over it to see inside, look in the mirror before sitting down to dinner.

Your trouble just has to be electrical. Next time it comes on, you'll need a helper. Have your helper watch the light, on while you are running the motor. Then wiggle the wire and find out if it stays on solid. If so, carefully pull the connector off of the sender. It should go out. But wiggle it again and ask if it stays out solid. The idea is to see if you can get the wire to short out to ground (usually just under the clamp at the front crank seal). If not, changing the sender ought to fix it.

There's a small chance I am wrong about this, and that there is indeed something interfering with oil pressure, intermittently. Some kind of embolism I don't know about yet... So, I'd feel a lot better if you proved this out sooner than later, or got your mechanic to look at it too. The usual problem is the wire.
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Art Benstein near Baltimore

Always keep your words soft and sweet, just in case you have to eat them.

Well I had this problem and the cause was a strange one.

Did you change your oil filter recently? I put one of the buy five quarts of oil and get a free filter onto Inga (86 245DL 271K). After the engine warmed up the oil light would come on and most of the time as you let off the gas and rolled to a stop. Changed the sending unit, replaced the wire, and then the contact.

Paid a pro to tell me I had over 80 lbs when the engine was started and over 50 when the engine warmed up. He changed the filter and the problem went away. It was an STP oil filter and bet that comes wrapped in several brand names (use nothing but Mann now)and it caused tbe oil light problem.

Now I have a dual VDO sending unit and a PSI VDO oil pressure gauge so I know how much pressure is out there under the hood. Still to this day 85 PSI at start up and over 50 at idle.

Hope this helps and regards,

Paul