Random whine from engine

[will.bates94]

3.0 B6 Tip trans, on cold start up it sometimes will whine very audibly, and sometimes it won't. I know its not power steering because the fluid is not low and its not the same noise. Once the car warms up, it does not make the noise at idle, but when you start driving even at low speeds the noise comes back. I also have the red oil pressure light that does not come on until the car is at operating temp, and intermittently goes away when the engine is under load. I never have the light pop up until the car is warm or after 15 mins of driving. Is it the oil pump that's making the noise? I'll try to make a video and post it later. My dad thinks its a vacuum leak but I can't find any broken lines or anything.

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[B44]

Vaccum leak wont trigger oil pressure light. Check your pcv valve and your serpentine belt.

[will.bates94]

How does the pcv make this noise? Because of crank case pressure changes?

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[imnuts]

So, you're driving the car with a red oil pressure light? I would be least concerned about the whining noise and most concerned about killing the engine due to oil starvation. In any case, check your SAI pump and hoses to ensure that they're all there, attached, and not broken.

[will.bates94]

As stated in OP all lines were checked with no damage. And yes its been this way for over a year now. It's not constantly on and is only on when the engine is experiencing low load or low RPM's.

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[SJorge3442]

If the RED oil light is on, you shouldn't continue to drive the car until you can verify the oil pressure is good. Sometimes cheap oil sensors will throw this light, other times its because the oil pressure is actually low. The oil pump on the 3.0 is next to impossible to replace and you're better off replacing the engine with a known, lower mileage unit.

First things first, solve the oil pressure light, then move on to other possibilities.

[will.bates94]

This is not my daily, and is by no means financially viable to replace the whole engine when the cost will be more than the car is worth. It has driven fine a whole 2 winters, 15k+ miles with the intermittency of the red oil light. I have checked the oil pressure at idle and it is within spec per the Haynes manual. I have yet to test it I'm driving conditions.

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[SJorge3442]

This is not my daily, and is by no means financially viable to replace the whole engine when the cost will be more than the car is worth. It has driven fine a whole 2 winters, 15k+ miles with the intermittency of the red oil light. I have checked the oil pressure at idle and it is within spec per the Haynes manual. I have yet to test it I'm driving conditions.

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You clearly state that at idle you don't get the oil pressure light. You only get it at low rpm's and low load. I would be more interested in knowing the pressure while underload, especially since this where the light is showing up. The whine could very well be because of oil related issue. Theres only a few things that should have a whine on this engine. Its gotta be something that it rotating. Whether that part is inside the motor or outside of it (pulley or accessory). Have you tried to turn the AC or defroster on when the whine happens? That could rule out one part of the car.

[will.bates94]

It is not the AC compressor, I have thrown on a shorter accessory belt to bypass the AC unit since it failed a while back. Again, I get the oil pressure light when I am off the throttle, NOT under load. At idle when cold I get no light, when warm and at idle I do get a light. I will be removing the oil pan and checking for blockage this spring when I bring my MK7 back out when the salty roads clear.

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[imnuts]

If the pressure is low under low load/RPMs, it is probably still low everywhere else, just not enough to trigger the light. Is the pressure above spec by a little or a lot? And why couldn't you test the pressure at other RPMs once the gauge was hooked up? It'd only take a person to press the gas pedal while you watch the gauge. If you want the car to remain usable, I'd figure out the oil pressure before worrying about a noise.

And if the sound is like a hair dryer, check the SAI system as I already mentioned.

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[will.bates94]

It is in fact a higher note sound, but the frequency or tone changes with engine rpm. It is not constantly the same noise. Almost changes the same way the power steering pump sounds when you turn it and its low. I only had a gauge with NPT threads, so I did not want the pressure increase to blow the adapter out and damaging anything like the threads in the block since I could only get a turn or so in, if it would even be possible.

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[CyberPMG]

1 - Get the car scanned to pull all codes so you can see what's going on behind the scenes.
2 - There's a reason why the red oil light comes on. It's something that should not be ignored.... especially when it's been happening for over a year. That light indicates a problem with oil pressure. Could be a problem with the sensor. Could be a problem with the oil pump. Could be something blocking the oil pick up tube. Refer to #1 to check codes.

I'm going out on a limb here and saying the noise could be coming from the valves sticking due to a lack of oil. That would also mean the rods would then be wearing down the cam lobes (source of noise) and would quiet down when the engine warmed up and change in tone with the RPMs. You may need to have the camshaft checked for any signs of excessive wear. Could also be an issue with cam chain tensioner (if the noise is coming from the back of the engine). You may also want to pull the oil pan to check for any debris and inspect and make sure there's nothing blocking the oil pick up tube.

Basically, get codes to see what was stored in the ECU (why the oil light keeps coming on). Do inspections around the camshaft and in the oil pan. I would refrain from driving it until you can address the issue.

[will.bates94]

No codes for oil pump. Code for torque converter, already replaced pressure switch and have run seafoam in the oil to deter any blockages. Next step will be to pull the oil pan and clean the pick up for sludge buildup. It can't be the sai because that only runs for a few minutes on cold start ups to get the cats up to operating temps... Going to make a video right now of it warm.

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[will.bates94]

To keep things simple:
When cold, engine either makes whining noise or it doesn't until a few minutes pass. Oil light does not come on at all.
Engine is warming up but not at temp:
Noise no longer resonates at idle, and only occurs with throttle.
When the car is warm:
Engine noises behave the same as warm. Red light comes on after 10-15 seconds off throttle while driving. Red light may sometimes come on at idle, may never come on at idle at all. When driving under load light does not come on. Under light driving load when driving slightly on decline oil light will come on and then go away.

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