Orange goo under oil cap

[iwearnosox]

There's some orange goo under the oil cap in my 99 jetta. Can't be good.

What's orange?

 

Moisture mixed with oil, this is normal for winter time driving, moisture is drawn in with the intake air, turned to steam in the combustion chamber and makes it's way past the piston rings ending up in your oil.

One good long highway drive will clear your crankcase of this.

(this is of course your engine runs fine with no symptoms of a blown head gasket)

 

[Eli]

Originally posted by: Roger
Moisture mixed with oil, this is normal for winter time driving, moisture is drawn in wioth the intake air, turned to steam in the combustion chamber and makes it's way past the piston rings ending up in your oil.

One good long highway drive will clear your crankcase of this.

Yep.

This is the reason you need to change your oil more often if you don't do a lot of driving.

 

[iwearnosox]

Thanks. I love this place.

 

As an added piece of useless data, the orange color comes from the acids, chemicals, sealants that find their way into the oil from your engine and the gasoline.

The PCV valve (Positive Crankcase Ventilation) does this wonderful service for you, on a good long highway drive, the oil temps stabilize at their warmed up temperature, this causes the impurities to boil off, the PCV valve then sucks these impurities into the intake manifold to be burned once again.

(The PCV valve is directly connected to a vacuum source on the intake, the valve regulates the airflow)

 

[MichaelD]

Roger is the man when it comes to anything w/an internal combustion engine.

 

[Analog]

Originally posted by: MichaelD
Roger is the man when it comes to anything w/an internal combustion engine.

agreed!

 

[Eli]

Originally posted by: Roger
As an added piece of useless data, the orange color comes from the acids, chemicals, sealants that find their way into the oil from your engine and the gasoline.

The PCV valve (Positive Crankcase Ventilation) does this wonderful service for you, on a good long highway drive, the oil temps stabilize at their warmed up temperature, this causes the impurities to boil off, the PCV valve then sucks these impurities into the intake manifold to be burned once again.

(The PCV valve is directly connected to a vacuum source on the intake, the valve regulates the airflow)

Don't most older cars just vent into the air?

Older lawnmowers do, at least. Newer ones pipe the breather to the intake.

 

[slag]

i suppose if someone had put dexacool into your radiator and you blew a headgasket, that could also cause the same visual data, but its unlikely that is happening.

 

Don't most older cars just vent into the air?

Older lawnmowers do, at least. Newer ones pipe the breather to the intake.

Yes they do, my two older Corvairs (1962 and 1963) both have draft tubes that vent the blowby, this is not as nearly as efficiant as a PCV valve because the PCV system uses vacuum to draw the gasses out.

 

[DWray]

I'd still get it looked at by a mechanic, especially if still under warranty. It might be a blown head/intake gasket. I'd be watching my coolant level like a hawk, if it starts dropping or looking darker (from oil mixing in) you'll want to get that fixed before too long.

I am not a mechanic, I know very little about engines. However, I do know that loss of coolant + goop under the oil cap is most likely a blown gasket from my personal experience.

 

[Kadarin]

Originally posted by: Eli

Originally posted by: Roger
As an added piece of useless data, the orange color comes from the acids, chemicals, sealants that find their way into the oil from your engine and the gasoline.

The PCV valve (Positive Crankcase Ventilation) does this wonderful service for you, on a good long highway drive, the oil temps stabilize at their warmed up temperature, this causes the impurities to boil off, the PCV valve then sucks these impurities into the intake manifold to be burned once again.

(The PCV valve is directly connected to a vacuum source on the intake, the valve regulates the airflow)

Don't most older cars just vent into the air?

Older lawnmowers do, at least. Newer ones pipe the breather to the intake.

Interestingly enough, performance parts companies like Moroso make extraction systems that connect the crankcase to the exhaust system, and use the low pressure created by escaping exhaust to draw out crankase gasses to reduce pressure. This will work well on cars that have highly efficient exhaust systems with no backpressure.

 

[iwearnosox]

I should have stayed in school.

 

Interestingly enough, performance parts companies like Moroso make extraction systems that connect the crankcase to the exhaust system, and use the low pressure created by escaping exhaust to draw out crankase gasses to reduce pressure. This will work well on cars that have highly efficient exhaust systems with no backpressure.

Yes, this is done to reduce pumping losses, as the pistons move up and down in their bores, the volume behind the pistons (Crankcase) changes causing pressure build up and vacuum, drawing a large vacuum in the crankcase drastically reduces these pumping losses freeing up horsepower, this is especially critical on engines with small crankcase volumes such as the aircooled VW engines, if you look closely at a VW drag car you will see a vacuum pump (A backyards running air pump, found on older vehicles that pumps air into the exhaust) connected to the crankcase breather.

I do believe that aftermarket high performance parts suppliers now manufacture pumps specifically for this application.