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oil in air box
Posted: Sat Jan 25, 2014 1:06 pm
by hammersfan12
can anybody help, i looked in my air box today and there is oil in there. and are there meant to be 2 holes in the bottom of the air box. thanks
Re: oil in air box
Posted: Sat Jan 25, 2014 1:10 pm
by Speedtouch
Which car do you have? Oil in the airbox is usually a sign of either cylinder head or crankcase breathing issues.
Re: oil in air box
Posted: Sat Jan 25, 2014 1:10 pm
by hammersfan12
sorry, 325 m20.
Re: oil in air box
Posted: Sat Jan 25, 2014 1:16 pm
by Speedtouch
How much oil are you getting in there? The standard air filter box is a long distance away from the throttle body, so something must be quite wrong! And what does the inside of the throttle body look like?
Re: oil in air box
Posted: Sat Jan 25, 2014 1:19 pm
by hammersfan12
last time, it was quite a bit and the air filter was black. and the throttle body was barely anything though. and when you say breather issues, could it be the pipe.
Re: oil in air box
Posted: Sat Jan 25, 2014 1:23 pm
by Speedtouch
Yes, check all the breather hoses for splits. Also, with the engine warmed up and idling, spray WD40 or similar around the inlet manifold gasket - a brief increase in the idle indicates a leaking gasket.
Re: oil in air box
Posted: Sat Jan 25, 2014 1:26 pm
by hammersfan12
the gasket should be ok, as changed over a month ago. could it be when the inlet was off the breather pipe has not been put back right, and also where could i buy the metal pipe. thanks.
Re: oil in air box
Posted: Sat Jan 25, 2014 1:29 pm
by Speedtouch
Did you notice the oil in the airbox prior to changing the gasket?
If it's only been recent, maybe something wasn't put back right...
Which metal pipe are you referring to?

Re: oil in air box
Posted: Sat Jan 25, 2014 1:31 pm
by hammersfan12
not back then, reason inlet was off was doing the head gasket. and it's the pipe that stands up straight from the case to the inlet manifold and has the spring on it.

Re: oil in air box
Posted: Sat Jan 25, 2014 2:22 pm
by Speedtouch
And did you notice any bore wear while the head was off?
I expect the pipe is available from the stealers or Cotswolds on here.
Re: oil in air box
Posted: Sat Jan 25, 2014 4:49 pm
by hammersfan12
by bore wear, do you mean the hole size. or something on the head. the head was skimmed and checked.
Re: oil in air box
Posted: Sat Jan 25, 2014 4:52 pm
by magpie
piston slap,bore wear in the block ...faint or none existing hone markings
Re: oil in air box
Posted: Sat Jan 25, 2014 5:05 pm
by Speedtouch
As above, plus there's usually a visible wear ridge at the top of the bore in the block.
Re: oil in air box
Posted: Sat Jan 25, 2014 5:13 pm
by hammersfan12
everything was ok, the marking were still on the barrels.
Re: oil in air box
Posted: Sat Jan 25, 2014 5:20 pm
by Speedtouch
Sounds OK then. Regarding your original post, I don't think there were any holes in the bottom of the airbox as standard, so someone probably drilled them in an attempt to give more airflow - this used to be a common mod, mostly on Escorts, etc.
Also, are you sure it's oil, and not some gunge that's been sucked in via those holes?
Re: oil in air box
Posted: Sat Jan 25, 2014 7:20 pm
by Demlotcrew
Do not spray wd40 near the inlet, it will destroy almost all the rubbers and it won't raise the idle one bit as it's no where near flammable enough. You need to use something like carb or brake cleaner.
Re: oil in air box
Posted: Sat Jan 25, 2014 7:42 pm
by G-Bear
Speedtouch wrote:Sounds OK then. Regarding your original post, I don't think there were any holes in the bottom of the airbox as standard, so someone probably drilled them in an attempt to give more airflow - this used to be a common mod, mostly on Escorts, etc.
Also, are you sure it's oil, and not some gunge that's been sucked in via those holes?
This is what I would guess could be the case. Get a replacement box from here, put a request up in the 'wanted' section. Along with a new filter. And see if the said oil returns.
Re: oil in air box
Posted: Sat Jan 25, 2014 10:19 pm
by Speedtouch
Indeed, or just blank off the holes with suitable plugs or Gaffa tape...
Re: oil in air box
Posted: Sun Jan 26, 2014 3:22 pm
by hammersfan12
thanks for the replies, the holes are only tiny. could be sorted with two screws. my dad did say to do it, when we looked a while ago and cleaned it out and changed filter. but i thought i'd see how it goes. also the pipe i was on about is the oil return pipe.
Re: oil in air box
Posted: Sun Jan 26, 2014 3:25 pm
by hammersfan12
oh and defantly oil, it's liquid and can smell it's oil.
Re: oil in air box
Posted: Sun Jan 26, 2014 6:53 pm
by Speedtouch
I would suggest cleaning it out, sealing up the holes, then check it again in a month or so's time.
Re: oil in air box
Posted: Sun Jan 26, 2014 7:03 pm
by hammersfan12
yeah, i'll give that a try

like last time i could tell somethings up as car starts to run a bit funny, guess because the air filter is getting dirty quicker than usual.