why does my oil light come on only when the engine is cold?

[sfarrell01]

I have 149K on my 1999 Beetle TDI. I love the car but it's quirky. I had my oil changed at a local Jiffy Lube. In the process the plastic filler tube broke so I got a new one at the dealer and Jiffy Lube installed it. I noticed when the engine was cold and I started the car the oil light would come on and beep three times. Jiffy Lube said they only put in 4.5 quarts and that everything was fine. When I got home, I checked the oil level on the dip stick and it was at the top of the first bend from the top of the dip stick. According to my owner's manual, this was too high so I took about 8-10 oz out. Now it's at the top of the flat section (with the hash marks). It still comes on when the engine is cold but only if the car istn't sitting level. Maybe its' still a little too high but if I had too much oil wouldn't the oil light come on when the engine is warm as well as when it is cold? Should I take out a little more or is there something else going on here? Please help.
PS Jiffy Lube used Pennzoil Syn Euro 5W40

[70autostick]

Hmmm,your sender unit could be gunked up.
I had a similar issue with my firebird(back in the day),changed the oil+filter,started 'er up,NO Pressure...!? The pressure sensor had been dirtied while flushing the oil.

My .02

Oh,check the oil while shes level,(as you may know)and let the bug sit for a bit after starting it,to allow the oil to drain from the cylinders,ect for an accurate reading.Clean the dipstick and re-check two,three times to be sure.
If she's level and the alert persists,don't worry,get 'er checked out at your convenience.

I'm not doubting your intelligence,just makin' sure


Good luck...

[MichelleRoze]

Originally Posted by sfarrell01

I have 149K on my 1999 Beetle TDI. I love the car but it's quirky. I had my oil changed at a local Jiffy Lube. In the process the plastic filler tube broke so I got a new one at the dealer and Jiffy Lube installed it. I noticed when the engine was cold and I started the car the oil light would come on and beep three times. Jiffy Lube said they only put in 4.5 quarts and that everything was fine. When I got home, I checked the oil level on the dip stick and it was at the top of the first bend from the top of the dip stick. According to my owner's manual, this was too high so I took about 8-10 oz out. Now it's at the top of the flat section (with the hash marks). It still comes on when the engine is cold but only if the car istn't sitting level. Maybe its' still a little too high but if I had too much oil wouldn't the oil light come on when the engine is warm as well as when it is cold? Should I take out a little more or is there something else going on here? Please help.
PS Jiffy Lube used Pennzoil Syn Euro 5W40

So the plastic filler tube....where you dip stick is? Broke during an oil change? That's NOT the filler tube. That's where the dipstick is. The oil filler hole is on top of the intake. If they haven't been using this to fill your car with oil, please stop taking it to Jiffy Lube. They may SAY they can change the oil on a diesel engine, but please, please don't trust them unless you know the mechanic personally and know they do good work. I've noticed that many new TDI owners have to learn this the hard way....myself included. Not all mechanics are DIESEL mechanics, especially cheap places like Jiffy Lube, Walmart, etc.

As far as the issue, did they show you the empty containers of the oil they used? Did they show you the new filter? Last time I had my cars oil replaced at a "cheap" place, they only put in 4.5 quarts, (which is ok, but it shouldn't be OVER full with only 4.5 quarts) My guess,....and this is just a guess.....did they change the oil filter? Sounds to me like it might be old and restricting the oil flow when cold. Or maybe it's gunked up or something.

To prevent this from happening...and worse things...please invest some time into the TDIclub there is a section with trusted mechanics by state that can work on your car for you and do it right! Increasing the life and reliability of your car.

[sfarrell01]

Thanks. I'll keep an eye on it.

Yes, I made sure the engine was warm, the car was level and I let it sit 10 minutes after shutting off the engine before taking any readings. It could be something gunked up. Also, if the dealership, where I had the previous oil change done, didn't use synthitic oil and only charged me for it, and Jiffy Lube didn't remove all the old oil, would the small mix of different oils cause a problem? The reason I'm thinking Jiffy Lube didn't remove all the old oil is because they said "the car only took 4.5 quarts" and the Service Manual (I find that better than the Owner's Manual) says it takes 4.7 quarts. To get the level down to the proper range, I had to remove 10oz.

[DZLBUG]

Please quit getting your car serviced at Jiffy Lube and the dealer. What oil have they been using in it? Its not hard at all to do yourself, and there are lots of other places that would be better to bring it to. I suppose they are selling you on 3k mile oil changes too? The interval is 10k miles with diesel rated 5w-40 synthetic oil, I prefer Mobil 1 Turbo Diesel Truck or Shell Rotella T.

How long is your engine cranking before it fires? If it is cranking a long time (it shouldnt be if everything is in working order) then the oil light will come on.

[sfarrell01]

I agree with your comment about budget places. The part that broke was the funnel

[sfarrell01]

The engine fires right up. There is no hesitation. I couple of seconds after it starts the oil light comes on and it beeps three times. After that it goes off and doesn't come on again until it sits for a longe time (8 hours)

[CoriBug]

So you know without a doubt that the dealer and Jiffy Lube used the correct synthetic oil for the TDI?? Did you see the empty bottles?

[DZLBUG]

Well whether they used the correct oil or not at this point isn't the issue with the problem at hand. Even if they used 15w-40 oil it shouldn't be doing that.

My concern would be that they incorrectly installed the oil filter and/or o-rings and possibly that they even put the filter in upside down. It would be hard to do as they would really have to smack it on there, but it has happened before. You need to get it looked at by someone who knows what they are doing. Whereabouts in CA are you located? It was a big state last time I checked.

If it is not oil filter related, I would replace the oil pressure switch which is down on the filter housing.

[ziptron]

Here is a similar answer, does a good job of explaining the sensors:
the oil light keep blinking with a beeping sound... - JustAnswer

1. Understanding how the system works
First of all let us understand how this system works. You have two oil pressure senders which are monitored by a control board located behind your speedometer. Both sensors are located in the filter flange. One is called the .2 bar sensor and the plastic part of it should be blue in color and the wire going to it is black. This sensor is for the oil light only (no flashing or buzzer). This is the same sensor that has been used on VWs for the past 30 years. It senses when the oil pressure falls below .2 bar (around 3 psi). At this point the sensor grounds itself and the light comes on. The control board only looks at the input from this sensor when the rpms of the engine are below 2000.
The other sensor is also located in the oil filter flange. This is the sensor that causes the oil light to flash and the buzzer to sound. You should see a yellow wire going down to this sensor. This is called the .9 bar sensor. The control board that monitors the two sensors only looks at this one when the rpms go above 2000. How is works is when oil pressure is above 1.4 bar (aprox 20 psi) the switch inside the sensor is closed. This grounds the sensor and this keeps the light off. It works the opposite of the .2 bar switch which comes on when it is grounded. As you rev the engine above 2000 rpm the control board looks at this switch to see if it is still grounded. If it is the oil light and buzzer stay off. If the pressure goes below 1.4 bar while the engine is above 2000 rpms then the switch inside the sensor opens (pressure holds it shut) and the buzzer and flashing light start.
2. Troubleshooting the problem
Now that we know how these sensors work we can start to troubleshoot them.
The very first thing to check if you are having this problem is the oil level. If you are low on oil your oil pressure can get low. This is why this warning system is there to prevent us from having problems due to an oil leak or our own negligence.
Next you want to be sure that your oil is clean and not diluted with gas. Smell the oil. Does it smell like gas? You may have a leaky injector that is diluting your oil. This will thin it and reduce your pressure.
What weight oil are you using? Always use the oil that is recommended in the owners manual.
What oil filter are you using? You want to see a black oil filter on the engine. Mann or Mahle or VW filters ONLY! Fram, Bosch, and any other color of the rainbow (blue, red, yellow, grey, etc.) can cause a low oil pressure condition so don’t use them.
Now that we have covered the basics you want to check the wiring to the 1.4 bar sensor. As we have said the sensor tells the buzzer and light to come on when the control board sees an open in the circuit. This could be caused by the sensor or it could also be caused by the wiring going to the sensor if it becomes broken somewhere along the run. You can easily test this by unplugging the wire from the sensor and grounding it to the engine of the car. If the wiring is good then your oil light and buzzer will stay off at all times. If there is a break in the wiring usually the buzzer and light will come on immediately upon revving the engine above 2000 rpms. At this point you are going to need to examine the wiring, try to find the break and repair it.
If you have grounded the sensor wire and it has made the buzzer and flasher stop the next step is to replace the sensor. You could check the sensor with an oil pressure gauge and wiring up a light to show you when the sensor is grounding or not but most folks don’t have the skill or equipment for this. If you do this is outlined in the Jetta Bentley Manual. If you don’t then I would suggest just buying a new 1.4 bar oil sensor as they are only $6 and they are a wear item that should be replaced every 100k miles or so. Be sure that when you get the new switch the plastic part of the body is gray in color and the part number is XXXXXXXXXX. This is the correct part number for this part. There is much confusion going on about this part and what the proper part number is so be sure to have the part number with you when you go to order this part to avoid getting the wrong sensor.
If you replace the sensor, plug the wire back onto it and you are still getting the oil light flashing with the buzzer then you need to have the oil pressure tested. You can do this yourself by purchasing an oil pressure test kit, or take it to a local shop and have it tested. You want to do the test with the engine warmed up (radiator fan having cycled on and off once). At 2000 rpm the oil pressure should be 29 psi or higher (29 psi is the minimum at 2000 rpm). If your oil pressure is below this then you probably have some worn engine parts like rod or main bearings and you should start saving money
for an engine rebuild.
If you have your oil pressure tested and it is above the minimum then you probably have a problem with the control board that controls the buzzer and flashing light.
This is built into your instrument cluster so you may have to replace the cluster to fix it if it comes to this.
At this point you have three options. You can continue to have the oil light flash and the buzzer come on at random intervals (very disturbing to say the least) and just ignore it (not a good idea but many people do). Second choice would be to continue to try to track down the problem by replacing the instrument cluster, etc. This can get expensive. Or you could go with the third option which would be to install an oil pressure gauge and just ground the sensor wire to the engine. This way you can monitor your oil pressure yourself with the gauge and the buzzer and light will never come on again. The flickering oil light will still work below 2000 rpm so you will still have the idiot light at idle. Many people do this and it is a good idea to install an oil pressure gauge so that you can know what is going on with your motor. You could mark the danger zones on the gauge with red tape just incase someone besides yourself is driving the car.

[O 16581 72452 5]

Being overfilled would not cause this issue either.

Chalk another up to not taking it to Jiffy Lube.

[cep]

ziptron, that was a nice explanation but this is a TDI, not a gas engine. It doesn't use a spin-on filter.

It is all well and good to bash Jiffy Lube (I hate their guts, too), but I'm doubtful if they caused this problem. Oil pressure is not a function of oil level until it gets so low that the oil pump doesn't pick it up--then you have zero oil pressure. Too much oil can cause frothing and excessive oil consumption but it is not going to affect oil pressure such as the OP's symptoms describe.

Since VW's are known to be a bit flaky electrically, AND they use two electical sensors to measure oil pressure, I would suggest taking it to a shop and having the oil pressure checked with a mechanical gauge. That way you'll know what the actual oil pressure is. If it's OK, then you can decide if you want to chase this annoying electrical gremlin or just ignore it.

[Lew]

You really need to run the Vag Com on this car. Autozone will scan for codes free. Take it there and see what codes come up if any. Post up there findings.

[noR]

Tell me this is an impossibility:

Oil dipstick tube broke. Chunk of plastic from the tube fell into the oil pan.
Chunk of plastic now wedged in the pick-up tube and causing flow-problems.


I think it's a possibility; but I don't know for certain.

If I were the tech I'd have inspected the tube and all the orange pieces of plastic that I could get up off the concrete to make sure the whole thing was still outside the engine.

[O 16581 72452 5]

Originally Posted by noR

Tell me this is an impossibility:

Oil dipstick tube broke. Chunk of plastic from the tube fell into the oil pan.
Chunk of plastic now wedged in the pick-up tube and causing flow-problems.


I think it's a possibility; but I don't know for certain.

If I were the tech I'd have inspected the tube and all the orange pieces of plastic that I could get up off the concrete to make sure the whole thing was still outside the engine.

Would take a hell of a chunk of plastic for it to clog the pick up and when the car was shut off, the plastic should fall back in the pan when suction was lost.

I say drop the pan and investigate, doesn't take long and the only hard part is the bolts between the tranny and engine. While you're at it, learn to do your own oil changes and not worry about the possibility of Jiffy Lube screwing up something in the future.

PS: Shops are pretty crooked, they can say they put that oil in it, but you can't be sure. I have a friend that worked at a shop, he never felt like going back to switch the oil in the machine and put cheap 10w-30 in everything that came in. I bitched at him when i saw him do it, but he just shrugged.

[Smileybug]

My fiance's step-mom took a car of hers to a Jiffy Lube or similar place for an oil change. They drained the transmission fluid instead of the oil, and then filled the oil so the car had double the amount of oil it needed. Needless to say, the car grenaded itself.

Run far, far away from Jiffy Lube and go to a local shop or do them yourself. Its super easy.

Also, I know this was brought up, but were they filling the oil through the dipstick tube, since they apparently referred to it as the filler tube?

[70autostick]

August of 09,i had thought i defeated Jiffy Lube's incomp. by buying my own oil+filter (Mobil 1) for them to change out,sure enough,on my way outta the garage,my driverside rear tire flew off and across 3 lanes of traffic...Damn free tire rotations,none the less,two were fired and i was 200$ richer

(I always change my own oil,but i was in a hurry,for i was already late for my trip)

So,yeah,they blow...