Jump to content

Top of Engine (Intake) Witness Stain Question

Recommended Posts



I just opened the top lid on the engine to replace the air filter. Inside the engine compartment was very dry and dusty except for the distribution tube and resonance tube...there was a witness of an oil film. (The other parts that show no dust are clean and dry and have been in contact with the underside of the noise deadening from the cover).Intake.JPG.c3ccc234bd5f27e97f26afa55ec88a61.JPG


The car has used no oil since I brought it 2,000+ miles ago and it does not drip any fluids so I was surprised to find this witness film. With the engine being so dusty a few drops of oil would go a long way...


Anyone know what might be causing this?


Is there a breather tube that might be blocked?


Is it easy to disassemble these parts for further inspection?


Thanks for your input in advance.

Link to comment
Share on other sites

is that the power steering reservoir cap behind the bellows ? that could be the oil leak source if it was over filled once . check any AOS /intake hoses too 

Link to comment
Share on other sites

Extanker, yes it is the power steering reservoir. It's a possibility.


The reservoir is pretty full. Up to the max.


One advantage of the dust on the engine is you can see where the slight oil stain is easily.


I have no smoke, no misfire, no codes but I have just ordered a AOS replacement and will have a good look when I replace it just to be on the safe side.





Link to comment
Share on other sites

Why...it can't hurt can it.


I will do it myself. £70 total then good for another few years.


Also, I will check all AOS hoses are clear.

Link to comment
Share on other sites

Ok. Replaced AOS today. 


PITA Job due to access to clips on bottom 100mm long hose so ended cutting hose and replacing with new.


Nothing at all found. AOS was clear, pipes in and out were clear and no oil found on intake or vacuum tubes.


I think the engine has just accumulated 12 years of grime and has never been cleaned so that's my next job.


Oh well, peace of mind and only cost £75 in total. And the AOS from Design911 was a genuine Porsche part.



Link to comment
Share on other sites

  • 1 month later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...

Important Information

By using this site, you agree to our Terms of Use We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.