Motor oil inside intake manifold

[Freeman]

Good day to all.
Today I started working on replacing the intake manifold. When I removed it, I found some motor oil inside. The channels supplying the mixture to the cylinders are also slightly coated with oil. Where does it come from? The car does not consume oil. I always keep the level just below the maximum.
I would be grateful for your suggestions and answers.

 

[bbf2530]

Good day to all.
Today I started working on replacing the intake manifold. When I removed it, I found some motor oil inside. The channels supplying the mixture to the cylinders are also slightly coated with oil. Where does it come from? The car does not consume oil. I always keep the level just below the maximum.
I would be grateful for your suggestions and answers.

Hi Freeman. Not sure just how much “motor oil“ you are seeing in the intake manifold, so only a long shot guess here: Do you use an aftermarket, oiled engine air filter in your Town Car?

I am sure others will jump in to help, so keep us updated and good luck.

 

[Action]

Generally, that would be from crankcase venting. (PCV)
All engines generate blow-by into the crankcase. This creates pressures. That pressure has to be relived and that relief is handled by venting the crankcase into the intake, somewhere to be burned with regular air/fuel mixture.

However, only the blowby is desired to be burned not any regular engine oil. There are various ways to separate the oil from the vapor.
And the modular engine used different ways to vent the crankcase. Typically, off of the left valve cover to the intake.
The crankcase vent does need to be serviced (cleaned) from time to time.

The above is a guess as to why there is oil in the intake.

Questions -
How many miles on the vehicle?
Would you post a picture of the left side of the engine? Specifically the left valve cover.
Is the oil you found evenly distributed around the intake or is found more in one area?

Action

 

[alumarine]

As Action said, it's probably from the PCV.
When I did mine there was a film of oil on the intake runners and maybe a tablespoon of oil sitting in the well under the throttle body.

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[11MarkX]

According to many auto mfrs, a little oil is "normal". Check throttle body. (pic is supposedly "normal" amount of oil, but most oil is in the black intake hose ).

However my opinion any oil is bad. Oil reduces octane, meaning lower power and also clogs up the catalytic converter/sensors.

The only exception is during the early years of direct injected engines. Since no fuel is going past the valves to lubricate them, valve seats last longer when there is a little oil blowby going thru the intake.

I was thinking of installing an oil catch can, but I'm not an auto engineer and I've screwed up some engines in the past by installing aftermarket garbage, so I'm not doing that. I have 90K on my MKX and no problems so far.

If its excessive, clean the crankcase vents/PCV. Check for vacuum leaks. Change to a better breathing air filter, since clogged air filters will do this too. I hope all goes well.

 

[Freeman]

Good day to all.
The car is produced in 2007.
The odometer shows 79.5K miles.
Air filter is original 1.5k miles. Before me, there was also an original and clean filter. The car, according to CARFAX, has driven about 7K miles over the past 6 years. The last five years before me it was owned by very elderly people from Long Island.
The inside of the motor looks clean. I would say like new. This car has a dashboard reminder to change the oil every 2K miles or so.
I understand that on this car the oil separating system is located inside the valve covers? To clean you need to remove them.
Maybe try playing with additional oil separators?
To judge the amount of oil, I am attaching photographs.

 

[alumarine]

That amount of oil is just fine, nothing to be concerned about.
Are you replacing the coolant crossover pipe under the manifold?
If not, take some emory cloth and remove the rust spots on the current one.
If the metal looks fine with the rust removed, slap some paint on those spots.

 

[Freeman]

That amount of oil is just fine, nothing to be concerned about.
Are you replacing the coolant crossover pipe under the manifold?
If not, take some emory cloth and remove the rust spots on the current one.
If the metal looks fine with the rust removed, slap some paint on those spots.

Thank you for bringing this to our attention. I admit, I didn’t do anything with this pipe. In the photo you saw she looks very scary. In reality everything is much better. I decided that it had not rotted in 15 years, and then it would serve for another 10 years. If I do any work under the car, I will definitely try to paint the problem area to stop the rust.
I will add photos so that you can more objectively assess its condition.

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