I have conducted a leak test and I'm hearing air leaking around these valves - I have removed the F Hose and it was in great shape, so the only thing that could be leaking around there is one of these valves. Has this happened to anyone? If there anything else in that area that could be the source of the leak? When the car is running, I can still get 0.6 bar. I have a tune, I should get 1.0. During the test, it won't hold 1 PSI.

 

I guess I answereed this myself... These are refered to as "Diverter Valves" by the community here. It is common for the OEM parts to fail. I have ordered some new APR diverter valves because they maintain a diaphram technology instead of opting for the "piston" type which are more suceptible to lubrication failure. I just have a tune, so I am not pushing a lot more than stock boost.




I will post a followup once they are installed.

 

I prefer the stock units, relatively inexpensive, and in most cases, better fitment. Some (not all) aftermarket valves require maintenance. No experience with the APR units. Good luck.

https://www.ecstuning.com/b-assemble.../06a145710nkt/

 

I run these also. Had my tune for 3 years. No issues. Never had to change them - I did them preemptively when I got the tune.

 

the cross terminology can be confusing. dv's vs recirculation valves.
my first 996tt had the oem's and one "split" causing the infamous honk, but no identifiable leak. replaced with 710n.

this 2nd car has had the evoms units on it for 14 years at least. never an issue.

 

Update - The new DVs are in - Wow! I was expecting my boost to be fixed (and it is) - I am now pushing 1.0 bar on a quick pull.

What I wasn't expecting... I bought the car with 70,000 Km. Gradually, the fuel consumption rose from about 12.3 to 15.3 liters/100 km. I now have 242,000 km on the clock. After installing the DVs, I reset all counters and half way through the tank, I'm showing 11.5 litlers/100 km. Who knew the DVs would make such a difference in fuel consumption. The car seemed to be running great before, so slowly degrading DVs will be easy to overlook. If you are still using stock DVs, I would suggest replacing them - you can't neccessarily tell that they are no longer functioning at 100%.

 

Wow!

 

I just replaced mine from an unknown brand billet to a forge 008. You can see how they're both piston type but one has an oring to create the seal. Much happier with the new forge I got

 

Those look nice, but I'm just wondering how often you would have to remove them to re-lubricate...

 

Agreed, I had those exact ones on my Audi B5 S4, and I ended up selling them as I didn't see a huge benefit over the 710N's. Access to them on the Audi was also a helluva a lot easier than the 996 Turbo. Everyone has their preference, as long as they work

 

From what I read the 710N made by karcher is not as reliable as the Bosch. And relubricating is 3 screws vs having to pull the whole assembly to replace. I'm happy with the build quality. I also tested the springs it came with, the green released at 10 psi and yellow (which I'm running) released at 20. I also just had turbos redone and working on the tune

 

When mine were leaking I simply tightened them up and that solved the leaking problem for me.

 

I'm not sure what you mean... OEM DV's are not adjustable?! (OEM has spring type constant tension clamp)

Update, I just can't believe the fuel efficiency improvement. I filled up yesterday and after a day of mostly highway driving my consumption was 10.0 ltrs/100km (28 mpg). I've never seen numbers that low since I bought the car!

 

when i re-located recently i had to keep pace with a truck for 1k miles and saw about 28mpg too. astonishing lol

not easy to drive this car at 60 mph average for that long. whew.

 

I had the problem too. When I removed them, I didn't see any cracks or failures, but the problem was that with the boost, the "valve" slid on the port, leting air pass through...
Maybe because of the high boost, or maybe because the rubber gets to soft over the time, I don't know. To me those parts are not well designed. The principle is not good, it's not mecanical.
I bought forge DVs with springs. I mounted them as the compressed air pushes the springs from the "F" hose (others mount it the other way), you've got to select the good spring amongst many present in the kit (each color spring for each boost pressure), and no problem for me anymore. Honestly, it maybe missing some place under the hood due to their bigger size.