Why does my oil light flicker on only when I idle?

[I_Know_Nothing]

My oil light flickers on when I idle, but only when I idle in drive. If I'm at an intersection and change to park, it goes away. I'm not sure if this has anything to do with it, but my engine shakes just a little(maybe loose motor mount), but it shakes less when I am in park. I also notice a foul smell coming from my heater, and I think it smells like burnt oil, but I'm not sure. I check my oil level and it is just fine. I got my last oil change a few weeks ago.

[Myglaren]

Have a look around the throat of the oil filler and the coolant filler openings - is there a scummy whitish residue there. This would indicate a blown cylinder head gasket with water vapour being forced into your oilways.

The original symptom appears to indicate low oil pressure, possibly caused by one or more of the following:

Clogged oil filter or pickup strainer (could be caused by the above if the filter was changed along with the oil)
Worn oil pump gears.
Worn bearings - main bearings and crankshaft journals in particular.
Or hopefully a defective oil pressure sensor.

Hang around for Rick to come along and shoot me down in flames and give you a more precise diagnosis but relying on experience, those are the points I would look into first.

[Booker57]

If you are lucky it is just a bad sensing unit. Most are fairly cheap <20USD. Change it (or have it done) and see what happens

[Rick]

Well the first step would be to accurately check the oil level. Do this by either parking the car on level ground for several hours or by checking it with the engine fully warm, and shut off for at least 2 minutes. On many engines low oil level = low pressure. Also oil that has not been changed in a long time can have a lower pressure at idle.
The shaking would tend to indicate a low idle speed when in drive, which can also cause low oil pressure.
The burnt oil smell tends to indicate a leak, and a poor seal at the rear edge of the hood. (A rubber seal at the rear of the engine compartment that sticks up and pushes against the bottom of the hood when closed.) This seal, not only keeps the oil smell out, it also would keep any leaking Carbon Monoxide out of the inside of the car.
My advice
Check the oil, add or change as necessary.
Check and adjust the idle speed as necessary
Repair any leaks.
If that does not solve the problem then
Do a oil pressure test with a mechanical gauge
If bad, the problem is internal (and probably expensive) If OK
Verify that the wiring to the sender is intact and not grounding out anywhere.
If that is OK, replace the sender.

[John Carter of Mars]

Originally Posted by I_Know_Nothing

My oil light flickers on when I idle, but only when I idle in drive. If I'm at an intersection and change to park, it goes away.,snip> ...my engine shakes just a little(maybe loose motor mount), but it shakes less when I am in park. ,snip>... I check my oil level and it is just fine.

These three things make a low engine idle speed the most likely explanation. That's the easiest and cheapest problem to solve, so I'd start there.

[Rick]

Originally Posted by John Carter of Mars

These three things make a low engine idle speed the most likely explanation. That's the easiest and cheapest problem to solve, so I'd start there.

I still think adding 2 quarts of oil would be cheaper.
(look up one post)

[Schuyler]

Originally Posted by Rick

I still think adding 2 quarts of oil would be cheaper.
(look up one post)

Look up to the OP.

Originally Posted by I_Know_Nothing

I check my oil level and it is just fine.

This is for the OP - I know Rick knows this, probably better than I do.

Oil pressure is roughly proportional to engine speed (at least until the pressure-relief valve opens) - this is due to the oil pump being positive displacement. But your low-oil-pressure idiot light is set to illuminate at a set pressure. So, when your idle speed falls too low, the idiot light goes on. (The same thing happens when your turn off your engine - the light comes on - except at that point you aren't thinking about the problems of low oil pressure.) There's little load on the engine at idle, so this may not be a problem, or it could be an early warning sign of problems to come. If the light goes out when you bump up the idle speed, things may be OK - or you could get this checked by measuring the pressure with an accurate mechanical gauge (or having a mechanic do this). Good luck.

[Rick]

Originally Posted by Schuyler

Look up to the OP.

Three hours sleep, that is my excuse and I am sticking to it.

[Tuckerfan]

What's the make/model/year of your car? And roughly, how many miles do you have on your car? Checking the oil level is certainly the first step, but if that's full, then you could have real problems. Your oil pump might be about to fail. In addition to the problems that's been mentioned, you might have a crappy oil filter. which could be causing the problem. Having the oil light come on is not a good thing at all. Without proper lubrication, you're adding wear and tear to the engine. Another problem is that for some reason, the idle on your car could be too low and having that adjusted could correct the problem.

When was the last time you had the oil changed on your car?

[I_Know_Nothing]

Originally Posted by Tuckerfan

What's the make/model/year of your car? And roughly, how many miles do you have on your car? Checking the oil level is certainly the first step, but if that's full, then you could have real problems. Your oil pump might be about to fail. In addition to the problems that's been mentioned, you might have a crappy oil filter. which could be causing the problem. Having the oil light come on is not a good thing at all. Without proper lubrication, you're adding wear and tear to the engine. Another problem is that for some reason, the idle on your car could be too low and having that adjusted could correct the problem.

When was the last time you had the oil changed on your car?

I have a 97 Sebring convertible with about 145000 miles. I don't think it has anything to do with the oil filter because I got my oil changed not too long ago and these symptoms were happening both before and after I got it.

[Eleusis]

Originally Posted by Rick

I still think adding 2 quarts of oil would be cheaper.
(look up one post)

Meh.

You forgot like at least "x" things:

The oh yeah, like, I'm sure
The bad connection in the dashboard
The short circuit in said above
The motivator
The car is Jonesing
The mechanic is on my nuts
The responder is drunk and/or stupid

[Eleusis]

Ps.

SAND!

[Eleusis]

In all seriousosity.....

"Sender" = "Oxygen sensor"?


Cuz oxygen sensors really do suck.

[Rick]

Originally Posted by Eleusis

In all seriousosity.....

"Sender" = "Oxygen sensor"?


Cuz oxygen sensors really do suck.

Dude, WTF?
A little too much Christmas cheer?
Anyway in this case the sender in question is the oil pressure sender, often called an oil pressure switch.

[Eleusis]

Originally Posted by Rick

Dude, WTF?
A little too much Christmas cheer?
Anyway in this case the sender in question is the oil pressure sender, often called an oil pressure switch.

I could ask you the same thing... (I'd prolly be out of line though)

Could not the "Sender" mean several different things"? Surely several things "send" shit to the computer? Including the O2 sensor?




P.s. Maybe.

[Rick]

Well since the tittle of the thread is Why does my oil light flicker on only when I idle? I thought it fairly safe to assume any reference to a sender in this thread would be about a sender concerning oil pressure. Also despite their rather confusing name, Oxygen sensors don't sense oil pressure, they sense Oxygen.
::: scratches head:::
Guess I was wrong about it being obvious.

[Eleusis]

I'm sorry, of course, you're obviously the expert on cars.

I was just making a joke....?....

If you're a mechanic, and you don't get it, then maybe you should search on O2 sensors and the BS surrounding them with regard to incompetent mechanics.

[Eleusis]

P.s. I searched... and found nothing....


Maybe it's just local....


But anyway, EVERYTHING is the oxygen sensor.... unless it is.




Excuse me while I go pass out.

[danceswithcats]

Umm-that's right-the oil light flickerator circuit is low on oxygen, so it needs to be readbusted to be in synch with the frequency of the piston return springs, otherwise it can result in carbon buildup of the muffler bearings.

[Contrapuntal]

Originally Posted by Tuckerfan

When was the last time you had the oil changed on your car?

A few weeks ago. Not me. The OP.

[John Carter of Mars]

Christ on a fuckin' crutch!

*Reads OP again, once again carefully noting all factors the OP has stated*

*Repeats previous statement from post #5, above*

Originally Posted by me

These things make a low engine idle speed the most likely explanation. That's the easiest and cheapest problem to solve, so I'd start there.

[Gary T]

Many cars will have a flickering oil light at idle if the engine idle speed is low. Usually there is not a mechanical problem with the oil pressure. However, the only way to be certain is to test the oil pressure with a mechanical test gauge.

The V6 engines used in Sebring Convertibles don't have a stellar reputation for durability. For that reason it may be wise to test the oil pressure.

Having some engine shake at idle suggests the possibility of a performance problem causing both the shake (known) and a low idle (suspected).

Properly used, the term sensor refers to a device giving input to the vehicle computer (e.g. oxygen sensor, throttle position sensor, camshaft sensor). Sending unit (= sender) refers to a device giving input to a gauge or warning light (e.g. oil pressure sender, temperature sending unit, fuel tank sending unit). Unfortunately, the terms are often used improperly. To further cloud the issue, some vehicles send gauge info to the computer, and on some the jobs previously done by separate sending units and sensors are combined, e.g. doing away with a temp sender and using a temperature sensor to both instruct the computer and run the gauge.

[Rick]

[quote=John Carter of Mars]Christ on a fuckin' crutch!

*Reads OP again, once again carefully noting all factors the OP has stated*

*Repeats previous statement from post #5, above*[/QUOTE=me]
Hell dude, you can do better than that, read post #4

The shaking would tend to indicate a low idle speed when in drive, which can also cause low oil pressure... Check and adjust the idle speed as necessary

[John Carter of Mars]

Originally Posted by Rick

Hell dude, you can do better than that, read post #4

Well Rick, I did read post #4. I always read an entire thread before posting.

You do, indeed, touch on low idle speed. You also included a number of other things such as:

Well the first step would be to accurately check the oil level. On many engines low oil level = low pressure.
and
Also oil that has not been changed in a long time can have a lower pressure at idle. just to list a couple.

Then you come back with this in post #6:

Originally Posted by Rick

I still think adding 2 quarts of oil would be cheaper.

Would you have him dump two quarts of oil into an already full crankcase?

The OP clearly indicates that these things are not the problem. I sought to simplify for the guy with the problem, by not mentioning things that he had already eliminated.

Not that his problem must be low idle speed. It's only about, say, 99% probable that the problem is low idle speed.

Note my closing sentence: "That's the easiest and cheapest problem to solve, so I'd start there."
Do you disagree? If you wouldn't adjust the idle first, where would you start, given that the oil is fresh, the filter is new, and the oil level is not low?

In the meantime, we got lengthy discussions on everything from sensors to sand. Why, when a quick idle adjustment will in all likelihood solve his problem?

[Rick]

As I mentioned in post #8 I was working on 3 hours sleep and I missed that he had checked the oil.
Next a rough idle is not always caused by a low idle speed. Bad motor mounts, a misfire, among other things can cause a rough but not low idle.
Since on many new cars idle speed is not adjustable, I do not agree that re-adjusting the idle is always the easiest thing to do.
If you are going to fault trace this in a systematic manner, you will work your way though all the possibilities starting with the most common and working to the truly weird.
Checking the oil level and condition would be first. Especially since the OP stated he smelled what could be leaking oil on something hot.
That would be followed by idle speed check and adjustment*, and then verification of the actual oil pressure with an external gauge.




*In the case of a non adjustable idle or misfire this would entail a repair not an adjustment. Repair could be cleaning of the throttle plate, or a parts replacement.

[John Carter of Mars]

I'd say that rough idle+flickering oil light in "D" + no flicker in "P" =low idle RPM. That's where I'd start.

I don't want to have three hours sleep, so g'day, Mate!

[I_Know_Nothing]

It looks like my car doesn't have an idle adjustment screw and I have to take it to the shop to get it adjusted. Go figure. Why are Sebrings so screwed up under the hood?

[I_Know_Nothing]

Originally Posted by Rick

*In the case of a non adjustable idle or misfire this would entail a repair not an adjustment. Repair could be cleaning of the throttle plate, or a parts replacement.

I guess I overlooked that statement when I posted my last comment. It looks like another trip to the mechanic. Thanks everyone for the input.

I found out that if I put my car in park when I'm at a stop light instead of idling in drive I never get the bad smell. I don't know how the two(oil light and smell) could be directly related but it seems like they are.

[Tuckerfan]

Originally Posted by I_Know_Nothing

It looks like my car doesn't have an idle adjustment screw and I have to take it to the shop to get it adjusted. Go figure. Why are Sebrings so screwed up under the hood?

AFAIK, idle adjustment screws went out with carbs and fuel injected engines don't have them.

[Uncommon Sense]

OP, is the Yellow check engine light on?

[I_Know_Nothing]

Originally Posted by Uncommon Sense

OP, is the Yellow check engine light on?

No. It's the red oil light.

[Uncommon Sense]

Originally Posted by I_Know_Nothing

No. It's the red oil light.

Right, the reason I asked if the check engine light was on is because it would indicate an emission control issue that could affect the idle (causing the oil light to show). You'd have to clear that up before the idle problem could be resolved.

Was the check engine light on at some point and then stopped coming on?
The reason I'm focused on the CE light is that if there was an idle issue or an emission issue it would normally show up on the computer and code out to send a signal to have the check engine light come on.

How does the car shift from drive to reverse (should be quick and noiseless) and what's the overall performance like? Shift and accellerate good?

[John Carter of Mars]

You do understand that after you get this car repaired you are obligated to report the results here, right?
After all this, we are gonna' wanna' know!

[I_Know_Nothing]

Originally Posted by John Carter of Mars

You do understand that after you get this car repaired you are obligated to report the results here, right?
After all this, we are gonna' wanna' know!

Of course. The repairs are going to have to wait until next week, but I'll report what happens, assuming that the mechanic can figure it out in the first place. Most places I've been to aren't that great at figuring out weird little quirks like this one. It does sound like a Car Talk question though.

[I_Know_Nothing]

Originally Posted by Uncommon Sense

Right, the reason I asked if the check engine light was on is because it would indicate an emission control issue that could affect the idle (causing the oil light to show). You'd have to clear that up before the idle problem could be resolved.

Was the check engine light on at some point and then stopped coming on?
The reason I'm focused on the CE light is that if there was an idle issue or an emission issue it would normally show up on the computer and code out to send a signal to have the check engine light come on.

How does the car shift from drive to reverse (should be quick and noiseless) and what's the overall performance like? Shift and accellerate good?

The engine light was turning on and off before I got my car inspected(in Texas) a few weeks ago. It failed the emissions test and they replaced the throttle body and some other part, and now the check engine light doesn't turn on anymore. I did read in the repair manual that a recently replaced throttle body can cause the idle to be off so hopefully thats the problem. But, when I first got the car about a year ago, someone at the oil change place told me I had a loose or bad(I can't remember the exact word) motor mount. He said it wasn't bad but I might need to get it fixed eventually. Since I never noticed any bad shaking, I never worried about it, especially since my car doesn't noticable shake while I'm driving, only whene I idle, and even then, it's doesnt' shake all that much.

As far a shifting, it works just great. It accellerates great also, though I try to be a little gentle because it has 140,000 miles on it.

[I_Know_Nothing]

Originally Posted by Tuckerfan

AFAIK, idle adjustment screws went out with carbs and fuel injected engines don't have them.

Shows you how much of an expert I am , but a mechanic I was talking to at a bar once told me that the Sebring had the highest labor cost of just about any car on the road.

[Tuckerfan]

Originally Posted by I_Know_Nothing

Shows you how much of an expert I am , but a mechanic I was talking to at a bar once told me that the Sebring had the highest labor cost of just about any car on the road.

Rick would be the expert on the labor cost, though considering that a mechanic once told me to never darken his door again with my 1988 Lincoln Continental, I'm skeptical that the Sebring's higher.

And if you had your oil changed at Iffy Lube, Rick will be more than happy to edumacate you on why that was probably a bad idea.

[Schuyler]

Originally Posted by I_Know_Nothing

But, when I first got the car about a year ago, someone at the oil change place told me I had a loose or bad(I can't remember the exact word) motor mount. He said it wasn't bad but I might need to get it fixed eventually. Since I never noticed any bad shaking, I never worried about it, especially since my car doesn't noticable shake while I'm driving, only whene I idle, and even then, it's doesnt' shake all that much.

Just a WAG, but I wonder if there's an oil leak that's somehow getting onto the engine mount that was mentioned - motor oil will degrade the rubber in an engine mount. Could be something simple maybe, like a valve cover gasket.

[I_Know_Nothing]

Originally Posted by Tuckerfan

Rick and if you had your oil changed at Iffy Lube, Rick will be more than happy to edumacate you on why that was probably a bad idea.

I don't, and won't ever, get my oil changed a Jiffy Lube or any other similar concept. I know they they have a habit of ruining peoples drain plug gaskets(not sure if thats the right term, but I refering to the gasket that prevents the oil drain plug from leaking). I'd rather change the oil myself. I go to a kind of mom and pop immigrant place and I feel pretty comfortable with them. They won't smile at you all the time like when you go to Firestone, but I know I don't walk in with dollar signs on my forehead either.

[I_Know_Nothing]

Originally Posted by Schuyler

Just a WAG, but I wonder if there's an oil leak that's somehow getting onto the engine mount that was mentioned - motor oil will degrade the rubber in an engine mount. Could be something simple maybe, like a valve cover gasket.

I have a very minor oil leak. I'm not sure if its really a leak or if I'm just burning it. I put in about a quart of oil between my 30,000 mile oil changes. I thought that might be where the smell was coming from, but since it only comes from my heater after I idle, and only after I idle in drive when the car is warm(basically when my oil light comes on), it doesn't seem to me that that would be the problem. I never see oil on the ground where I park, and the parts of my engine I can see when I lift up the hood don't show any obvious signs of a leak. It's possible that it could be leaking more on towards the bottom, but judging from the small amount of oil I need to add(not to mention my completely ameature opinion) over a 30,000 mile period, I doesn't seem like that's where the smell is coming from. When I take my car in next week I'm going to get a diagnosis on my moter mount. Would that have anything to do with my oil light situation, or is that a completely separate issue.

[Gary T]

Originally Posted by I_Know_Nothing

I put in about a quart of oil between my 30,000 mile oil changes.

I hope you mean 3,000 rather than 30,000.

I thought that might be where the smell was coming from, but since it only comes from my heater after I idle, and only after I idle in drive when the car is warm(basically when my oil light comes on), it doesn't seem to me that that would be the problem.

If it's a hot antifreeze odor, it's likely a small leak in the heater core. This would be accompanied by a gradual drop in the engine coolant level. If it is indeed a hot oil smell, I would guess that the fumes are coming in with the air for the heater, in which case they should also come in with the "vent" mode.

When I take my car in next week I'm going to get a diagnosis on my moter mount. Would that have anything to do with my oil light situation, or is that a completely separate issue.

Separate.

[I_Know_Nothing]

Originally Posted by John Carter of Mars

You do understand that after you get this car repaired you are obligated to report the results here, right?
After all this, we are gonna' wanna' know!

I've never resurrected a thread before but I finally was able to get to the shop. Here's the verdict:

The shaking was from my motor and transmission mounts being bad. He replaced those and the difference is amazing. I never thought my 150,000 mile engine would ever feel like that again.

My mechanics theory on the oil light was that my broken compressor was taking power from the engine. I don't know the exact details, but this one belt runs three things, including the compressor, which has never worked. I was always careful not to run the AC for this reason, but I just found out that the defroster uses the compressor that that's what probably did it. I have not had any problems in two days now so I think he was right. The weird thing is that now my engine light is on. Could replacing the engine and transmission mounts or bypassing the compressor with a smaller belt have anything to do with this?

[Gary T]

Originally Posted by I_Know_Nothing

The weird thing is that now my engine light is on. Could replacing the engine and transmission mounts or bypassing the compressor with a smaller belt have anything to do with this?

I don't see how, unless something was inadvertently left disconnected.

[I_Know_Nothing]

Oops. I was in a hurry and and it looks like I left out my mechanic's solution to the problem. Since I don't have the money to to replace the compressor, he just found a smaller belt that bypassed the compressor but still fit aroung the other components(you'll have to forgive me that I don't know what they are).

[Uncommon Sense]

Thanks for the update.
Could the compressor (not being on the belt) cause the engine light to come on? I don't know, but it's possible.

You should take it back to that same mechanic and have them put it on the analyzer to find out why the engine light is on NOW, since it wasn't on when you took it in to them.

[staceym83]

I bought my car and was able to drive it for one week before it broke down. The car lot I got it from stated that they done an oil change as well as replacing all sorts of things regarding the oil system. That whole week I drove it I kept getting told that I just needed to replace the bulb because it was going out. The car idled funny and the light flickered when setting at a stop light or sign. Soon as I would start driving again it would stop flickering. Now a month after it broke down I find out that a push rod has gone through the head gasket. The oil level was checked repeatedly and was always where it needed to be. What would have caused the push rod to go through the head gasket? I've only has the car 5 weeks and was only able to drive it the first week. Any help or ideas would be greatly appreciated.

[beowulff]

Originally Posted by staceym83

I bought my car and was able to drive it for one week before it broke down. The car lot I got it from stated that they done an oil change as well as replacing all sorts of things regarding the oil system. That whole week I drove it I kept getting told that I just needed to replace the bulb because it was going out. The car idled funny and the light flickered when setting at a stop light or sign. Soon as I would start driving again it would stop flickering. Now a month after it broke down I find out that a push rod has gone through the head gasket. The oil level was checked repeatedly and was always where it needed to be. What would have caused the push rod to go through the head gasket? I've only has the car 5 weeks and was only able to drive it the first week. Any help or ideas would be greatly appreciated.

First of all, it's NEVER a bad bulb!
Your engine obviously had oil pressure problems - it could be any number of things (bad oil pump, bad bearings, etc.). Hate to tell you, but it's probably not worth fixing.