Intake smoke test leak - resonance flap shaft seals

[Gwsinc]

Evening all

Using a smoke tester I have found a small air leak in my intake manifold. My car is pre-varioram so it has one resonance flap tucked away beneath the throttle body. The leak is at the interface between the rotating part of the resonance flap shaft and the manifold itself, see phot below for the exact location (phot is of a 964's intake from google, but it is in the equivalent place on my 993!).

Before I take it all apart to find out for myself, does anyone know what kind of seal is in there? Is it s standard o-ring or a lipped seal or something else?

The PET shows nothing of value unfortunately and I've done all the usual searches online.

Also - I now have a smoke tester so happy to smoke test anyone's intake if you're in the Hampshire area!

 

[Gwsinc]

I think I've already answered my own question.

Looks like I need two G8x12x3 lip seals, one for each end of the shaft. See the link below for an interesting thread on Rennlist: https://rennlist.com/forums/993-for...-in-the-connector-piece-of-throttle-body.html

Will post some pics with a DIY once I get it sorted in case this is affecting anyone else. Looks like this is often a source of oil on top of the engine, as well as a vacuum leak.

 

[guards red]

Hi,

This is very interesting - what prompted you to leak test the car's engine? Did you have a fault you were chasing?I assume it was running too rich?

Also, what smoke tester did you get?

Sorry for the 20 questions, but it sounds like an interesting project.

Regards
GR

 

[Gwsinc]

Hi,

This is very interesting - what prompted you to leak test the car's engine? Did you have a fault you were chasing?I assume it was running too rich?

Also, what smoke tester did you get?

Sorry for the 20 questions, but it sounds like an interesting project.

Regards
GR

Hi GR

No worries.

I've had some fairly common symptoms such as a slightly lumpy idle, an engine that should be smoother and basically other vacuum leak symptoms, as well as a squeak on heavy acceleration. I'd triple checked every connection in the intake, so I was convinced the issue was elsewhere and was starting to think I was being 'over sensitive', with many of these issues accepted as normal by some if you read through this site and rennlist.

I bought the cheapest well reviewed smoke machine on Amazon: https://www.amazon.co.uk/dp/B09FT6P...i_i_385WXN6SC1Y0YXKYV5A3?_encoding=UTF8&psc=1

works exactly as described and pushes out a couple of PSI of pressure which is all you need.

I bought the seals from Wych bearings on Sunday night and they were delivered today. Took about 2.5 hrs to dismantle everything and fit them. Have driven about 30 miles this evening and all symptoms seem to be solved

I'll put a diy up here at some point but for now have posted some photos to my Instagram below.

 

[guards red]

Thanks for that, much appreciate the information and the link.

Might think about purchasing one, looks useful, doubt you'd have found your issue without it.

Regards
GR