Standing fuel/oil in throttle body

[TwistedFish]

Hi all, found another problem with the Ex... I was taking the MAF out to clean it today, decided to take all of the hosing off, looked in the throttle body, and what do i see? In the back, theres some standing black liquid. Now im assuming this is gasoline, because that would make the most sense, and thats what it smells like, but it's possible oil is mixed in as well. I say this, because i have an oil leak. Mostly the oil drips from the pan, where it seems to leak out of somewhat randomly (meaning i can't find the source of the leak, just that the pan is pretty much covered in oil, so that any time i touch anything around there really, i get oil on my hands). Anyways, anyone know anything about this? I've been using the ex as a learning experience, and as a project truck, but this one has me stumped. Additionally, (this pertains more to the oil leak than anything) I have also found my spark plugs to have their threads coated in oil. Not all of them, but both of the "backmost" i believe (closest to the firewall). Could this be related? Thanks.

 

[Kesp4.0]

Not sure what fluid it could be, but there's a good chance that its black simply because of all of the soot that can build up inside the throttle body/upper intake and the fluid mixed in with said soot

 

[Roadrunner777]

If memory serves, on the plastic duct from the MAF to the throttle body, there is a rubber hose that vents the crankcase, so that could be oil vapor residue.

 

[TwistedFish]

Not sure what fluid it could be, but there's a good chance that its black simply because of all of the soot that can build up inside the throttle body/upper intake and the fluid mixed in with said soot

yeah but like... is this an issue? or the norm?

 

[TwistedFish]

If memory serves, on the plastic duct from the MAF to the throttle body, there is a rubber hose that vents the crankcase, so that could be oil vapor residue.

the above posts make it feel like this isnt really an issue... any way this would cause harm to the engine?

 

[Roadrunner777]

I suppose I would wipe it clean with some solvent and check it again in 1,000 miles... but I think this is just an accumulation of years of use. It's not harmful. The engine design vents the crankcase so some oil vapor accumulation is expected.

 

[Nadams01]

the above posts make it feel like this isnt really an issue... any way this would cause harm to the engine?

I saw it on mine too. Could be a FPR leaking fuel from the diaphragm back to the vacuum line and causing a fuel build up as well. Take the vacuum line off the fuel pressure regulator and see if it reeks of fuel.

 

[92exp4x4]

It's blow-by from the PCV system. A little oil in the intake is normal. It comes from the vent tube that goes from the oil filler to the intake tube. Generally if you have a lot of oil in there, it can indicate excessive wear on higher mileage engines.

 

[410Fortune]

Now im assuming this is gasoline, because that would make the most sense, and thats what it smells like, but it's possible oil is mixed in as well.

It is oil, as these guys stated your crankcase is vented through the valve cover and into your intake tube. See the rubber tube that runs from the oil filler neck to the intake? That is for "blow by" which is oil ..........vented back into the intake so the oil can find its way back into the engine, any fuel vapors can be burned, etc.
Also right there at the bottom of your throttle body is another hose, this is the fuel vapor feed to the intake. Fuel vapors from the top of the fuel tank are stored in the charcoal canister and then sent to your intake, via the throttle body, to be burned up through the intake. So this is why you find a small puddle of oil that smells like fuel. Totally normal. However a small puddle = excessive oil = excessive blow by = worn piston rings = old engine. Nothing to really worry about unless you have compression issues / dead cylinder

I have also found my spark plugs to have their threads coated in oil. Not all of them, but both of the "backmost" i believe

Very very very common for the old OHV engine to leak oil from the valve cover gaskets. This oil will go everywhere..... but mostly all over the rear of your engine because the fan is always blowing air rearwards. So the plug threads will be wet with oil until you clean the area and fix the valve cover gaskets. OIl pan leaks are also common, but can easily be confused with some other common leaks from the ohv, like the dipstick tube leaks, oil pressure sender leaks and the big one is the oil filter mount O rings leak.......all of these leaks will leave oil around the lip of your oil pan.

Hope that helps clear things up

 

[Gary Crist]

It is normal.

An easy way to explain it is easy to understand is this.

Down shift, let off the gas and let the motor brake.
Manifold pressure will be lowest but, the cylinder will still
be "pressurized". The crank case now is pressurized, PCV
is closed and now the crank case vent tube at the top
where the black gunk is the avenue for crank case gases to escape.

 

[Carsusa]

I saw it on mine too. Could be a FPR leaking fuel from the diaphragm back to the vacuum line and causing a fuel build up as well. Take the vacuum line off the fuel pressure regulator and see if it reeks of fuel.