Replacing the check valve is not very difficult but you cannot reach all the bolts to loosen the reservoir properly so you have to really pry it out. I did it using wood handle and two wires to get the flexible pipe out of the valve seating.... Sorry , don't know why , cannot uopload pics ????

I've used Castrol Syntec 5W40 and the growling came back after 800 miles. I've decided to replace it with Mobil TDT, the growling was there the next day but less sensitive and after over 500 miles almost completely gone. Why??? Sorry I don't have a clue, May be ZDDP... But I am not celebrating yet , need may be another 1500 miles before calling it the best solution for my engine.....

 

Mine clicks when I first start it and then it goes away once it's warmed up and you only hear the IMS rattle. From past experience w/ my BMW 335, which made the same noise, I believe it's a valve lifter. I will take a video tomorrow. Rainey, I only wish my 996tt sounded like yours lol.

 

maybe one question give you a answer....do i have lifter with part number 996 105 255 020 or 996 105 255 023...ore the new version 996 105 255 025

 

I wouldn't bother replacing the check valve since the TSB for the issue states that the low pressure warning light would come on at start if it needs to be replaced. If your light doesn't come on don't bother replacing the check valve. This topic has been discussed many time on 6SO, rennlist, renntech, and all come to the same conclusion, if there is no light its normal. I guess if you want to avoid the noise just drive the car more and enjoy it.

 

I have one of the early TT engines (2000).....61k miles, but if it sits no more than a week, it doesn't rattle at all at start up. It sounds pretty "tight" actually...

If I start it after more than 7-10 days, it rattles a tiny bit for 1-2 seconds.

I'm running Mobil 5w50.

 

This is my car after cold startup for not driving for a week. Scared the crap out of me when I first got it, but after it warms up, don't hear anything but the IMS rattle. The clicking noise at the beginning does still worry me though. Still have a noise though between 3-4k that sounds like IMS chirp though, but 2-3k nothing but exhaust.

http://www.youtube.com/watch?v=NkcpDE0694I

 

What you're hearing is one of your hydraulic valve lifters sticking. Once the engine warms up a little the oil flows better as it thins out and pressurizes the lifter and the clicking sound slowly goes away. If you jack up the rear of the car and lie down under the engine, you should be able to localize the cylinder that has the sticking lifter. There is nothing you can really do about it, maybe going to a thinner oil like the OEM M1 0w40 unless you are already running it....or drive the car more often.

 

Thanks pwdrhound. I was 99% sure it was a lifter I just couldn't figure out if it was a problem or not. When I had the same issue w/ my BMW, the tech told me the same thing basically. It was noisy, but if it goes away once the engine warms up, it was fine. Sounds like the same case here. I went with M1 TDT to try and get rid of the IMS rattle, but it doesn't quiet it down by too much and I've since gotten used to it now, so I may go back to OEM and maybe add a little ZDDP to prevent any future issue.

 

in most cases if a 996tt lifter makes clicking noises, it do not be possible to switch for the high cam profile....so you fuel consumption goes low and your power goes down....(you dont feel it...because it is only one intake valve of two per cylinder and it lifts 3mm instead of 10mm)


at this point check exactly your oilfilter....

 

I did an oil change a little while ago but found nothing. Gas mileage wise, I get about 16-20mpg while giving it a bootfull every now and then. I am due for an oil change in 1k miles so I may switch back to OEM and I'll take another look at the filter again.

 

if you didnt find anything in your oilfilter you are on the sunny side.......i have found some particles in my filter...today my engine is out maybe on monday i know more...

 

Exactly what my 996TT does. It only does it after sitting a few days and lasts a few seconds. My guess is if it is lasting longer he may have some thick or old oil in there? Is your oil pressure OK? Sea foam may loosen up that lifter.

 

mine sound exactly the same in video above...then i found particles in olfilter...i changed my oil and filter and after that i found only one ore two particles again...i changed my filter again and after that i found nothing....

today my engine is out and i will clear this situation....next week i know more.

 

What exactly is involved in changing out lifters? If I have to pull my motor for a gt2 clutch upgrade would this be an easy job with motor out?

 

Keep me posted winnigt2, I would like to see what happened to your engine if mine is moving down the same path.