Strange stuff in intake - should I be worried

[ischmitz]

When I took the 3.6 out of the car for some maintenance I noticed some strange foamy stuff in the intake.

Background: This is a 964 3.6 engine in a 74 Targa with 32k miles on a full rebuilt. The crankcase breather is hooked up straight to the oil tank and the other line from the oil tank is hooked up to the intake elbow of the 3.6. I put a restrictor in that line, too. It is not the stock cone-shaped brass piece. I used a long aluminum spacer with a 10mm inner hole instead.

I first noticed a rusty oil filler cap a couple of month ago. The inside of the cap and the dip stick both showed bad corrosion (read: rust). Further, there was some foamy deposit in the oil tank filler neck. I cleaned that up and replaced the dip stick.

Now with the engine out of the car I got what appeared to be water dripping out of the rubber hose from the oil tank to the intake. I then took the line off at the intake elbow and the entire line is filled with a waxy, foamy stuff smelling like gas/oil. See here for a picture. Yuk



What is that stuff and do I have to worry about it?

I took the entire intake system apart and cleaned up all the oil inside. Any ideas what do about this?

[mjshira]

Ingo

What type of oil do you run?

[fanaudical]

My opinion: Looks to me like oil/water/fuel sludge. This forms in engines that don't reach a high enough oil temperature to boil all the fuel/water from the oil or can form in breather lines that don't have enough draw (and so the vapor cools and condenses in the breather line).

You may have inadvertently created a place for that to collect and cool by adding the restrictions to the breather line.

[Cooper911SC]

That is what happens when moisture and oil vapor mix.

I have worked on several client vehicles with this.

Often caused by cars sitting for long periods and being driven short distances.

If the car doesn't get "hot" and run for longer periods 50 miles plus at speed the moisture/condensation won't get burned off and evaporate from the system.

Cooper

[ischmitz]

I run Castrol 20W50 dino.

The car is unfortunately mostly driven to and from work these days. It's 12 miles per way and that would qualify for short-distance I guess. I try to drive it like I stole it and got the evil eye from a couple of co-workers already when I drove "circles" around them on the off-ramp... If I push it any more its jail time.

I also had it up to the bay area twice in the last month and that's a healthy 300 miles one way. I would think one of these trips would clean out moisture but maybe not.

Maybe I need to get to the track again to really clean it out. I noticed that when coming back from the track the black stuff from the exhaust tips would be burned off.....

[fasterlaster]

Originally Posted by ischmitz

Maybe I need to get to the track again to really clean it out. I noticed that when coming back from the track the black stuff from the exhaust tips would be burned off.....

I'm not great at following my advise, but try and take the long way home at least once per week. There has to be some fun roads somewhere.

[Bill Jennings]

One thing that concerns me is that you drive it like you stole it but do not get it warm enough to evaporate the condensation. You might consider longer drives and waiting for it to fully warm up to operating temp before driving flat out. My car was gunged up with milky oil at the oil filler cap when I bought it but never seen it that way since. Maybe try taking the scenic route to work, it will clear the condensation, your engine will last longer and you will never complain about the commute again.
Just saying!

Cheers
Bill

[Nostril Cheese]

Oil condensation.

As the others said, re-work the line and go for longer drives.

[silverc4s]

Just a thought- the famous costal marine layer there in the summer months is really wet. If you take short runs in that stuff, your oil may get loaded with moisture..