Blinking Oil Light Indicator on dash

[elwesso]

Flushing the radiator wont help the clogged tranny heat exchanger line!!

What the heat exchanger is a tube that runs inside the radiator containing the ATF...... That line needs to be cleaned seperately..... Thats why on a lot of newer cars they have a filter just before the heat exchanger-- to minimize cloggin like this!

[Murphyg]

Thanx Wes thats good to know.
Another bit of info to add to the grey matter.
Im sure it will help in the future.

[rickko]

Here is the latest in this saga.

When I started this thread the car had 77k on it. Wednesday I took it into the dealership for its 90k service. This is the first time I've had 'professionals' touch the car other than a throttle body cleaning since I bought it with 72k miles on it.

OK, as I just said, a few months ago I thought I'd have the throttlebody cleaned 'cuz I got a coupon in the mail. Thought that might raise the idle enough to stop the light from occasionally flickering. As it turned out, it didn't. All symptoms remained the same as I originally described them.

Now lets get to Wednesday/Thursday (9/16/4). I picked up the car after their service and found as soon as it heated up the light started flickering again. The only difference, now it stayed on more than flickered. Again, A/C on, and at idle.

Oh, I forgot to mention in the off chance the problem might have been the oil pressure sensor (OPS) I had it changed out; $12 part, $110 labor!!!! Oh well....

Since I just picked up the car and only put about 7 miles on it at this point I drove it back to the service manager. They kept it overnight and called me this morning.

1st, at their expense they put in another new OPS. Symptoms remained the same.

Then they said, "Well, its either mechanical or electrical." I figured since the whole damn car runs on a computer, the chances are better that they'd find an electrical problem so I gave 'em permission to test the electronics ($102.00).

Late this morning I got called back to tell me the electronics were fine! No problems except when they tested the fuel gauge circuit the needle wavered from empty to full (it doesn't do that without the test equipment hooked up and running, only when it is hooked up).

The suspicion they voiced in regards to the gas gauge was (in so many words) that the instrument panel may be starting to go bad.

Back to the oil light problem. They said, "Electrics are fine. Its obviously a mechanical problem. That will take an engine disassembly to determine and fix the problem." They went on to say, "With the car on the lift, engine idling, there is an obvious 'clattering' sound coming from the oil pan area. Above idle it disappears.

Here's what I told them. "I'll live with the light flicker." If its mechanical and requires a teardown, then I'll drive it till it REALLY requires a teardown, or new engine.

So, thats where I ended up with this problem.

My opinion is, if you have the same problem, learn to live with it and enjoy the car. Ignore it as long as it always goes off once the car is revved off idle.

I am going to try one more thing which mentioned earlier but never did try, I'm going to run that High Mileage oil in it at the next oil change to see if that has any affect. Whether it does or not, I'll report it here!

Oh, if anyone with this same problem has converted over to the High Mileage oil and seen the problem subside or go away completely, let me know!

Lastly, one more thing came to mind. I've always run Pennzoil 10w-30 in the car. The dealership put in Castrol 10w-30. Maybe there is enough difference between the two brands that is the reason the light stays on more steady than it ever did with Pennzoil. Or, the new sensor is really more precise than the old one. Just more thoughts to ponder.

Oh, total cost for all this "investigation."

Throttle Body Cleaning 92.66
New sensor Installation 149.82
Electrical circuit checkup 102.00

Total! About $350.00! All to try and eliminate the light from flickering on the dash. I hope my experience, and money, helps you save your own money.
Please send contributions to..... hahhahaha

..rickko..

[AElayyat]

Hey rickko, first off is do you do your own oil/filter changes or have it done? Next suggestion is to use Castrol or Valvilne 10-w30 and replace one of the 7 qts of oil for 1 qt of LUCAS Engine Oil Stabilazor, stuff is about $8 for a qt. but it should help. This stuff does a good job as I was having similar problems with my 89 Deville and that cured the oil pressure light from flickering (in my case it turned out that it was the oil sending unit/switch).

[rickko]

AElayyat,

I don't think you read my last post correctly. The dealership used Castrol 10w-30 instead of what I use (when I change my own oil), Pennzoil 10w-30.

It sounds like your switch is similar to what is called an Oil Pressure Sensor on a Northstar. In my case, the original and two NEW ones all seemed to give the same response; a flickering oil pressure light at idle w/AC on while car is in Drive.

Since my engine has a tendancy to run through a qt. of oil every 800-1000 miles I will be adding something at that time. Probably will try 1qt of the high mileage stuff first. Then repeat at each successive 1k oil-add points.

Thanks for your suggestion.

..rickko..

[jonscat]

hey buddy
i have a 96 eldorado and i was having the same problem,it all began after i had the oil changed and the guy put 5w oil in the car because he said since it was a high mileage car that it need this type of oil,i am not very up to date on engine oil and took him at his word.shortly after this i noticed that the oil pressure light would flash ater the car had been driven awhile,especially in town i live in Atlanta and we have pretty rough traffic here,i took the car back to him and he checked the oil pressure and i was fine but of course the engine was not very hot when he checked.to make a long story short i called a friend that owns a GM dealership in Fla and he said that 5w was not the correct oil for engines with over 100k that if i would put 20w in that it would probably would take care of it since he knows my car and did not thinkl it was the oil pump.had it changed that day and the light has not blinked since.You may want to try this before sinking alot of money into it. Hope thei helps!! Jon

[oldgamer]

Some how I feel the high milage stuff not gonna help.
The oil with different viscosity can help, but I don't think that's going to be right solution, cause the engine designed to work with 10-30W. For me it seems like oil pump doesn't work right or clogged a bit somewhere.

[AElayyat]

Originally Posted by rickko

AElayyat,

I don't think you read my last post correctly. The dealership used Castrol 10w-30 instead of what I use (when I change my own oil), Pennzoil 10w-30.

It sounds like your switch is similar to what is called an Oil Pressure Sensor on a Northstar. In my case, the original and two NEW ones all seemed to give the same response; a flickering oil pressure light at idle w/AC on while car is in Drive.

Since my engine has a tendancy to run through a qt. of oil every 800-1000 miles I will be adding something at that time. Probably will try 1qt of the high mileage stuff first. Then repeat at each successive 1k oil-add points.

Thanks for your suggestion.

..rickko..

My bad rikko, I kindda skimmed through your last post, but if the oil pressure sensor/switch is not the problem next thing that comes to mind is that your oil pump is starting to go so have that checked out.

Regarding the other members suggestions about the thicker weight oil, wouldn't a thicker oil cause the oil light to stay on longer? I'm thinking thicker oil longer time it takes for the oil to circulate??

[jonscat]

hey guys
the mechanic told me that the thinner weight oil would get hot quicker and thin even more therfore causing the oil pump or oil pressure not to be as good as if it was thicker.he he put it on some diagnostic machine that test the pressure and with the thinner oil it had less oil pressure only had 10lbs of pressure then when he put thicker oil in it it had 20lbs.i am not mecahnically inclined and have no idea what all this means other than i drove it to florida with no pressure problems.oh i forgot to mention that the low oil pressure reading stop engine had came on 1x before i had the different oil put in.so it worked for my car but i guess i could understand why there would be some doubt as to how it would correct the problem.. let me know what you find out about yours as i may have someone check mine again.but so far i am driving with no problems...Jon

[JB 1]

I have a 91 DeVille and my oil light flickers as well also I'm currently using the Castrol high mileage and still experiencing the flickering light. At first I thought the worst but the engine doesn't knock and the oil level is fine. So does anyone have a suggestion, I've heard it could be the OPS or the oil sending unit. How do I know if I have either or are they the same. Peace

[rickko]

Four years later--- Update -- Mileage now 118,000.

Flicker problem has never gone away. So far the only fix I've found is to add a quart of oil when light starts flickering.

I really want to change the oil pump. Maybe some day I'll do that. When I do, I'll post if it helped. I've had the car for about five years now. I may end up selling it before I ever get a new oil pump installed as its getting along in time on the road but still runs great, gets good mileage and is as comfortable as it ever was.

I've been using the Pennzoil High Mileage oil now for about a year. That has had ZERO effect on solving this problem.

..rickko..

[billytheshoe]

I have seen this problem occur from out of spec. bearing clearances, Mains, rods, cams. I have seen this occur from hastily used tread sealer or other debris in the oil system that finds it way through to the oil sensor and partially plugs the orifice at the end of the sensor. After shutting down the engine the debris fall back off the sensor orifice. Upon start up it flows right back to the sensor orifice. A messy but easy way to correct this condition is to remove the sensor and crankover the engine for a few of seconds to purge oil out that sensor port.

[rickko]

Originally Posted by billytheshoe

I have seen this problem occur from out of spec. bearing clearances, Mains, rods, cam or from hastily used thread sealer or other debris in the oil system that finds it way through to the oil sensor ....

Well, it could be bearing clearances, but not other debris because it only acts up when the temperature is fairly warm, over 80. Otherwise all winter long it pretty much goes out. That's why I'm leaning towards the oil pump partly because if I add a quart of oil, the problem will go away for about 800 miles.

Thanks!
..rickko..

[billytheshoe]

It seen very odd that 1 qt. would make any difference in a system that holds 7.5 qt.s or more. Perhaps there is crud in the oil pump relief valve. I don't really know if the relief assembly can be serviced externally without oil pump removal. I know it has an external oil pump that would be very costly to replace as a whole assembly. I will add the problems I experienced on the oil systems regarding the small sealant chunks was for real and an epidemic proportions on dozens of new trucks that had many safe mode systems incorporated into them. The low pressure senders/switch were 6 psi and did not sound off/light up until they trucks were working with heavy loads at max operating temps. After changing out several switches one came out with a small chunk of a product known as Rectorseal stuck in the orfice. Rectorseal is a fine tread sealant product but needs to be applied to the pipe threads not over the end. Bad grounds and corrodide wires/connections will cause the same problems.

[Ranger]

Billy, if it where the check valve, wouldn't the oil pump loose it's prime after shutdown and have no oil pressure at all?