False “Reduce Oil Level” Warning?

Hi everyone. I am confused and my trusted mechanic is even more confused. Two months after my last oil change (on my 2015 Golf TDI SE Sportwagen) I was taking a road trip from Las Vegas to LA. Received a “Reduce Oil Level” warning. Checked the dipstick. Oil level normal. Wiped clean. Warning went away. Returned within one hour. On return to Vegas my mechanic checked it out. Confirmed oil level normal. Last week (3 months later) I had a routine 6 month oil change but decided, on my mechanic’s advice, to replace my oil sensor. He then tested the vehicle thoroughly. No more warning light until a couple days later driving on the freeway: same warning has returned. Checked dipstick again. All normal. Wipe clean. Warning went away for 48 hours. More freeway driving: warning has returned. Help!

There are steep mountains between Vegas and LA. Maybe the car angled enough for the oil to touch the high level mark/sensor.

BTW those things are called “idiot lights” for a reason. The sensor is dumb with zero intelligence. If YOU know the car is not overfilled then ignore the light. It is clearly incorrect.

If you put the oil at the top of the full mark when the oil is cold this will be too full likely. Halfway between full and add when cold is about perfect. When the engine warms and the oil expands it wont cause an issue. This may or may not be ur issue but its free to try.

GreenLantern_TDI said:

If you put the oil at the top of the full mark when the oil is cold this will be too full likely. Halfway between full and add when cold is about perfect. When the engine warms and the oil expands it wont cause an issue. This may or may not be ur issue but its free to try.

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I thought you were taking the crazy train, but I guess it does expand some.

https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3995932/how_much_does_oil_expand_when_

However, that 6% should be pretty negligible, and I can't fathom the sensor would alert the driver until it was significantly over full. [Like a quart or so, although this is just a guess on my part.]

I'm still leaning towards the system faultly displaying the overfill condition.

Thanks guys!

Same thing happened to me, first time the car was driven at freeway speeds for over 100 miles the warning went off. Dealer sucked out a little oil and no problems since.

BeetlePD said:

There are steep mountains between Vegas and LA. Maybe the car angled enough for the oil to touch the high level mark/sensor.

BTW those things are called “idiot lights” for a reason. The sensor is dumb with zero intelligence. If YOU know the car is not overfilled then ignore the light. It is clearly incorrect.

Click to expand...

Unless he's going off-road, road grade isn't steep enough. Max on highways is 6-7%, AFAIK...

I just crunched the numbers: 4.3 quarts (137.6 oz) expanding 6% is about 8.25 oz.

I guess the 2014 doesn't have this nonsense. I'm from the school of thought that a bit too much fluid is less bad than not enough.

tdiatlast said:

Unless he's going off-road, road grade isn't steep enough. Max on highways is 6-7%, AFAIK...

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You haven't been in areas with real mountains and hills / grades then....


I've been on "Highways" that had warnings for trucks about 10% grades.

My stop-sale GSW had an oil level warning issue from the beginning which turned out to be level sensor wiring modification performed by rodents while sitting on the dealer's lot for 1 1/2 years. Replacement of the wiring harnesses for the sensor and the power steering rack solved the problem.

The '15 TDI with the new engine got a level sensor that can read low AND high oil level. Rational was states requiring Bio-D would have some accumulation in the crank case and there fore raising the oil level.

Sooo, there are hot and cold marks on the dipstick, much like an automatic trans dipstick. Only fill to the COLD full mark. Also a simple solution is suck out a little.




1 - Compensation area for possible fuel entry. Do not fill or drain the oil.
A - Do not add oil.
B - The oil can be filled to the maximum limit -A-.
C - Add oil. The oil level must be at least in the upper half of the measuring range -B-.

At an oil level above the compensation area -1- the engine oil must be changed.
If the oil level is under the minimum mark -C- fill the oil, minimum of 0.5 liters

Jason

Thanks guys

Appreciate it