Oily intake

[Pablo M]

1972 2002tii

When replacing WUR hose I had to take off a few of the intake runners for access. 

Noticed the intake was coated in an oily residue. Tried to wipe it and it wasn’t wet. Looked like long term deposits. Would have had to scrape pretty hard to get it off. 
 

is this normal, or something indicative of s bigger problem? 
Its like a sandpaper texture. 
 

[2002iii]

Looks like a lot of carbon buildup, have you checked the valve seals?

[Hans]

Oil fog from valve cover vent?

[Mike Self]

1 hour ago, Hans said:

Oil fog from valve cover vent?

 

+ 1...that's the logical answer and indicative of a high crankcase pressure forcing the oil mist from the valve chest into the vent hose.  Looks long-term. 

 

Try softening it with carb cleaner and see if it'll come off easier...

 

mike

[jimk]

Does no harm, just don't look at it.

[72MetallicMalaga]

Some oil fog is normal, especially with these older motors, right? I have a crankcase vent and after driving i'll see some fog/smoke rising from the vent filter.

[Hans]

Are you losing oil? Maybe check compression.

I wouldn't get too fussed. 

[Hans]

How long have you been using the filter?

[72MetallicMalaga]

1 minute ago, Hans said:

How long have you been using the filter?

Few months now, i've had it since December

 

I barely lose oil, I think I had to put in 1/4 of a quart last time I checked, but i've also only put on about 700 miles since getting that filter.

 

I had a vent hose before, and I would find a couple sticky clear/amberish drips on the floor once every month or so.

[Pablo M]

15 hours ago, 2002iii said:

Looks like a lot of carbon buildup, have you checked the valve seals?

No. How do I check that? That's a bit above my pay grade but happy to try.

 

 

12 hours ago, Hans said:

Oil fog from valve cover vent?

 

10 hours ago, Mike Self said:

 

+ 1...that's the logical answer and indicative of a high crankcase pressure forcing the oil mist from the valve chest into the vent hose.  Looks long-term. 

 

Try softening it with carb cleaner and see if it'll come off easier...

 

mike

Valve cover vent? You mean the PVC hose? So I would expect the air cleaner interior would look the same? What you're saying is that there's pressure in the block (why?) and its causing some oil to get into that hose, into the air cleaner housing, then through the throttle body and into the intake, correct?

I mean, definitely looks long term and I'm not inclined to clean it, at least for a long time, as I have other issues to deal with. I'm just concerned if this was a sign of a significant problem.

 

When I had sorted (for the moment) the vacuum leaks the engine ran beautifully. A new vacuum leak developed now that I've driven it hard-ish, probably for the first time in its life.

 

 

9 hours ago, jimk said:

Does no harm, just don't look at it.

Perfect!

 

 

1 hour ago, Hans said:

Are you losing oil? Maybe check compression.

I wouldn't get too fussed. 

I haven't been able to drive it enough to know if its losing oil. When I got the car engine was caked in old seeped oil. Cleaned it up a bunch and now only see some wet oil residue between the Kfisher and the engine block. Also, revving the engine to 5-6K reveals blue smoke out the pipe. 😕

As long as the residue inside isnt indicative of a more serious problem I need to add high to my priority list, I'm good leaving it well enough alone lol.

 

Thanks all.

[2002iii]

A leak down test will tell you if your valve seals are leaking.

 

Leaking valves usually cause blue smoke on deceleration.

 

Blue smoke on acceleration usually indicates worn piston rings.

 

If it were my engine I would remove the intake and have it media blasted. I would also do a compression test if you haven't already. I would also use a boroscope to look inside the cylinders.

[Hans]

I'd be interested in learning how valve seals would cause carbon build-up in intake manifolds. Since that grunge is dry, I'm assuming that the vent filter is diverting oil fog from there. I would leave it.

Blue smoke in exhaust would indicate oil burning,  as above. Just monitor oil level regularly. Oil is cheap, engine rebuild not so much. Compression test will give idea of how much time is left.

[jimk]

1 hour ago, Pablo M said:

What you're saying is that there's pressure in the block (why?) and its causing some oil to get into that hose, into the air cleaner housing, then through the throttle body and into the intake, correct?

The vent on the valve cover is the only place to let the blowby out of the crankcase.  Gasses flow from a higher pressure source to a lower pressure area.

 

The small hose that is teed into the larger vent hose and connected to the throttle body on a Tii draws the blowby in the intake bypassing the throttle plate.  Only when the engine is worn out, blowby is great enough to push excess into the air cleaner housing.

 

It's not a true PCV system, more like a vent.

Edited March 3, 2023 by jimk

[ray_]

12 hours ago, 2002iii said:

A leak down test will tell you if your valve seals are leaking.

 

Leaking valves usually cause blue smoke on deceleration.

 

Blue smoke on acceleration usually indicates worn piston rings.

 

If it were my engine I would remove the intake and have it media blasted. I would also do a compression test if you haven't already. I would also use a boroscope to look inside the cylinders.

And if there's a little abrasive left in the intake after media blasting, it'll just help with the piston rings bedding in.

 

😉

[Pablo M]

22 hours ago, jimk said:

 

 

The small hose that is teed into the larger vent hose and connected to the throttle body on a Tii draws the blowby in the intake bypassing the throttle plate.  Only when the engine is worn out, blowby is great enough to push excess into the air cleaner housing.

 

It's not a true PCV system, more like a vent.

Mine doesn’t have the small hose teed into throttle body. TB had that plugged, which I replaced as it had dry rot and crumbled off. Vent hose goes straight from valve cover to air box only.