Help with engine noise

My engine is making a sound I cant figure out in the last few days. If you have been around Vortech superchargers when they are being spun at idle engine RPM (not the SQ quiet ones), my engine making a sound exactly like it. I listened to the alternator and A/C compressor since they are on top but I dont think either one is the culprit. The sound seems to be coming from the middle of the engine possibly below the intake. I replaced the oil separator a couple of months ago and have not checked the bellow but I am pretty sure that is not it. Another comparable sound is the A/C compressor on a Chevrolet V8 like Suburbans and Pick-ups when the clutch is engaged. It does not matter if the A/C is on or not, I believe ruling the compressor out. It is audible in the cab with windows up or down. 89k miles Tip, any ideas, TIA Cory

You can eliminate all external componants by removing the serpentine belt and running the engine. What oil is in the engine? Is the noise present on cold engine, warm engine, under load? Exhaust system tight?

OW-40, yea I guess I can remove the belt and check, the sound is in all temp ranges.

It is probably your Tiptronic transmission... your engine is rejecting it! Sorry, I can't help with the real diagnosis, so I thought I would give you a little grief about the Tip, Tippy.

You know what, the day I get a manual I going to thank Tim for always reminding what a dumb choice I made in trannies.

I hate to bump up but I got pushed to the end of the page.

Well, you know my recommendation. Dump the 0W40 and put some good oil in. If it's your lifters not pumping up, or looseness between bearings, you'll know right away. Obviously, it could be something unrelated to oil, but it is a cheap and easy way to get a direction. Throw in some 15W50. Does the noise diminish under load?

well since a 1/3 of the oil stays in during an oil change, I have a mix of 0W-40, 15W-50, and 10W-30 from past oil changes. I have a super blend, so I have a 8.3W-40

Less than 20% is the amount of oil a normal oil change will leave in the engine.

1/3??? Not sure I agree with that or even the 1/5 that 1999 suggests. I imagine it is close to the 20% if you just drain and fill versus letting the car sit for a while if you have the time (say 1hr plus) you can get quite a bit out, probably close to 90-95% easily.

So, you DO agree with me Dell. I said LESS than 20%. If I had said 5%, people would have been all over me for starting another oil thread. Additionally, Porsche manual specifically states that only 80% of oil will come out and I don't want to contradict Porsche....the Gods of automobiles.

idler pulley taake out the air box and start the car, ( use a bugee to hold the fill tube up and off the belt) start the car use a scre driver to touch the bolt for each idler pulley you should be abale to feel it and you can put the screw driver to your ear to listen beware of spiining parts and belts

I know it's against the status quo to agree with you but in this case I do. I guess my wording was quirky but what I was trying to say was there is NO WAY there is 1/3 of the oil still left in the motor after an oil change. I am sure more will stay in if you use 15W-50 instead of the "proper" 0W-40 since that syrup will stay stuck to the internals rather than flow Oh aren't the oil debates fun?

Doesnt the motor hold 12qts total according to the manual? If you refill with 8-9 quarts, that is a 1/3 to a 1/4 that stays in.

I agree with 99firehawk. My car was making a whirring noise like a very small SC was on the car. Indy just pulled the belt and spun the pullies and found the one making the noise.

My initial thought was that it was accessory related but it had a slight air type sound to it like an intake leak. This made me think the accessories and idlers were not it, but it must be. I am going to check this weekend along with my driveline "pop" like Cosmos is having. Thanks guys

drive line is a tranny mount

Oh Cory, what would make you think that? 12 qts??? Sounds like somebody needs to go back and re-read their manual.

Yes....you are right, it is 10.25 liters full capacity, 8.25 change quanity leaving roughly 19-20% in the motor after a change. This is referenced from a 996 workshop manual. We were all a little off.