what is the cause of oil in the inter cooler

[scoobygt]

as stated there is a lot of oil in the inter cooler and in the vac lines also spotted some around both the turbos outlets?

[funkytown]

are your head and crank case breathers plumbed into your intake..? if so,thats why

[lachlan]

normal

high kays ?

the reason people fit a catch can

engine head and cdank case breathers are vented into the intake so the engine can burn the vapours . some condense before reaching the engine and drop out in the intake .

cleaning the intercooler out is well worth doing . slosh petrol around in it will clean it . take it off the car first tho ...

[scoobygt]

not many other twin turbos to my knowledge are having my issue, its more the oil coming out the vac lines that is causing me issues e.g. vac lines fly off the black box then cause the car to go into limp mode.. could my motor have bad compression and would that cause lots of blow by?

[twinturboboy]

what advantages would you get from cleaning out the I/C?

[lachlan]

it can do its job properly . when the inside of it is covered in oil the charge air doesnt touch the aluminum of the intercooler .

kinda like sunbathing under a tarp . dont get much sun

yeah if vac lines are full you have issues . are all the breathers set up properly or has someone fiddled wiith one part of the system ?

[scoobygt]

the crank breather is bellow the throttle body? if so I\'ve got that venting to atmo, rocker cover breathers are plumed as usual, the inter cooler must be getting oil from some where, I think it could be my turbos

[Marky]

Crank case breathers are vented to the intake from factory for two reasons

A) Emissions - better to burn them off than vent them straight to air apparently

B) The vacuum effect from the intake helps keep the crankcase in a state of partial vacuum or at least try to

Some cars, when they\'re either a bit more tired or have looser clearances (say some race engines / forged motors when cold) will need this vacuum more than others, soon as you remove it they start to pressurise the crankcase a bit and then start forcing that vapour out the breathers anyway. Go to extremes and you get the venturi breathers some drag cars have where the breather uses the vacuum effect of the exhaust to vent the block... crazy

That\'s what a PCV valve exists for - it means venting when in vacuum, and stops boost getting into the block

Causes of excess oil in the intake / cooler will be either a tired motor - one running a heap of boost with a bit of blow by just breathing - or a turbo starting to have a cry about how it doesn\'t want to go on anymore and its allll toooo harrrd (which is quite likely for a high km TT legacy, that primary does a lot of work)

Watch a few youtube dyno vids, you\'ll often see cars all of a sudden pump out a heap of vapour from catch can breathers etc when they\'re running big boost. That on it\'s own is normal ish - once you start filling catch cans with oil & cleaning out intercoolers every fortnight, things aren\'t looking flash

That said - even a healthy motor will build up a film of oil over everything over time, that\'s why that subaru UEC stuff is part of the normal service for them, ditto for it doing no harm to give intake / cooler etc a clean out once in a while if you have it off already

[Stoffa]

+1

I had all 3 plumbed to a can with no vacuum on the crank case and I was using 3 litres of oil in less than 5000km on a brand new engine.

Too much crank case pressure can cause a pressure build up between the rings, especially if running higher boost than factory, the pressure escapes on the wrong side of the rings and takes oil with it.

Once I plumbed my PCV and breather back into the intake I stopped using oil.

IMO the best way is to use an air oil seperator or a closed loop catch can that still has vacuum on the outlet.

Im currently using an SM motorsports AOS similar to the grimmspeed and prova ones but it doesn\'t work that well.

...and before anyone shoots me down, some people dont have any issues running with a can vented to atmosphere, but it sure smells bad!!

[scoobygt]

well I might go to pick a part and get the factory set up, my turbos are low ks but it does run up to 18psi on primary and over 20 psi on secondary don\'t know how it does it never bothered to look tbh..