Oil in throttle body.

[RustedRanger]

I took my air intake tube off about a week ago to do some mods and there was a trail of oil from around the holes in the mouth of the TB into the air tube. I replaced the PCV valve (with a quality one) and then I had the tube off yest and there is still a little oil in the TB. I know how to work on stuff but this has me puzzled.

 

[tlthehun]

Oil vapor passes from the valve cover to the throttle body where it condenses and is perfectly normal?

My intake has some oil residue as well and the engine runs fine.

I use Redline synthetic in all of my vehicles. In the past when I had an air cooled motorcycle (1987 Yamaha FZ600) with just a small K&N air filter for a crankcase breather, I would smell oil vapor at low speeds. With a petroleum/dino oil, it was much more apparent than with a synthetic.

 

[Big Jim M]

Close...but no cigar here!

Oil vapor passes from the valve cover to the throttle body where it condenses and is perfectly normal?

My intake has some oil residue as well and the engine runs fine.

I use Redline synthetic in all of my vehicles. In the past when I had an air cooled motorcycle (1987 Yamaha FZ600) with just a small K&N air filter for a crankcase breather, I would smell oil vapor at low speeds. With a petroleum/dino oil, it was much more apparent than with a synthetic.

The oil NEVER vaporizes. What happens is a very fine spray is inside the valve cover, over time as the wear of the engine increases, BLOWBY pushes this fine spray into the throttle body.
And there ya have it!
Big JIm

 

[RustedRanger]

Thanks. My 2.9L seems to be running really good for 160,000+ miles so I kinda guessed it might be some blowby. I just remembered something from when I had a Chevette.....I often went to a website for Chevettes and remember a "catch can" type device some made to catch the oil from the valve cover breather to the breather. I unhooked my valve cover breather tube because it would soak the air filter with oil....literally.

 

[tlthehun]

The oil NEVER vaporizes.

If that's true, then why is there an API spec for it?

from wikipedia:

The NOACK volatility (ASTM D-5800) Test determines the physical evaporation loss of lubricants in high temperature service. A maximum of 15% evaporation loss is allowable to meet API SL and ILSAC GF-3 specifications. Some automotive OEM oil specifications require lower than 10%.

I know the smell of oil vapor when I scent it...

 

[Big Jim M]

Wow!!

If that's true, then why is there an API spec for it?

from wikipedia:

The NOACK volatility (ASTM D-5800) Test determines the physical evaporation loss of lubricants in high temperature service. A maximum of 15% evaporation loss is allowable to meet API SL and ILSAC GF-3 specifications. Some automotive OEM oil specifications require lower than 10%.

I know the smell of oil vapor when I scent it...

First you post that the vaporized oil reforms in the throttle body and then you go to wiki to prove you are correct.. which you simply aren't.

The astm d-5800 is a test to show how much oil dissapears in the crankcase from heat. Once the motor oil vaporizes it goes away as a vapor and doesn't return.
ALL oils are tested at high temperatures. ALTHOUGH the temps tested at are usually far beyond the temps reached inside the oiling area of an engine.
Several oils show a possible 10% loss in volume from these high temps.
How many of us see a 10% loss if oil on the dipstick from temperature? Not many i'm fairly sure.

So back to my first point. NO! Oil that has vaporized inside the valve cover of an engine will NOT reform inside the TB!
Big JIm

 

[tlthehun]

First you post that the vaporized oil reforms in the throttle body and then you go to wiki to prove you are correct.. which you simply aren't.

The astm d-5800 is a test to show how much oil dissapears in the crankcase from heat. Once the motor oil vaporizes it goes away as a vapor and doesn't return.
ALL oils are tested at high temperatures. ALTHOUGH the temps tested at are usually far beyond the temps reached inside the oiling area of an engine.
Several oils show a possible 10% loss in volume from these high temps.
How many of us see a 10% loss if oil on the dipstick from temperature? Not many i'm fairly sure.

So back to my first point. NO! Oil that has vaporized inside the valve cover of an engine will NOT reform inside the TB!
Big JIm

Try reading for comprehension, it does wonders.

I speculated that oil vapor condensed in the throttle body. Granted, I could have been clearer than with my wording rather than relying on punctuation but everyone that I know would have understood.

I stated that I could smell oil vapor when I rode my FZ600.

You stated that "oil NEVER vaporizes".

George W, is that you?

 

[Acepilot1023]

Kids, let's play nice now.

The whole reason for the question is whether or not the oil in the throttle body is okay. We have reached a conclusion, thus the thread should be dead.

 

[RustedRanger]

I put motor oil in my vaporizer when I'm feeling congested........