brown ooze inside cylinder head

[bp944]

I'm in the process of replace the head gasket, quite slowly. (Turns out I know less about engines than I thought). When I removed the intake manifold, the cylinder intake port has a brown slimy residue on it. Any guesses as to what it is? I'll post pictures tomorrow night or so.

I'm replacing the head gasket because I believe the head gasket is blown. There's coolant in the oil, white smoke, does hold idle well, etc. I'm just praying its a gasket and not something else.

Cylinder head removed: Please look at pictures below.

[AA_Ezra]

Head gasket or oil cooler, might as well do the oil cooler too if it has not leaked yet it will eventually

[John_AZ]

Originally Posted by bp944

I'm in the process of replace the head gasket, quite slowly.

(Turns out I know less about engines than I thought).


When I removed the intake manifold, the cylinder intake port has a brown slimy residue on it. Any guesses as to what it is? I'll post pictures tomorrow night or so.

I'm replacing the head gasket because I believe the head gasket is blown.

There's coolant in the oil, white smoke, does hold idle well, etc. I'm just praying its a gasket and not something else.

You bought the '87 944 knowing there was water in the oil.

Replace the oil cooler housing seals. You need a special alignment tool for the OPRV valve or it will bind. The tool costs about $50.

You have coolant in the oil, Porsche says you must replace the rod bearings.
(read bottom). Remove the oil pan and get new rod bearings, rod nuts, oil pan seal.



Have the head machined to check for damage and out of spec tolerances.

Do not scratch the block surfaces when you remove the old gasket.

Keep the lifters/followers in the same order (bore).

Check the lifters for softness by pressing in the piston (stem). If any can be pressed in with little force replace the lifter.

Keep the lifters soaked in oil. There is a tiny hole on the side of a lifter. Keep the hole "UP". Fill the lifter hole with oil from a syringe.

More?? Much more....

GL
John

[Cocacolakidd]

While you are in there make sure you replace the AOS seals/0'rings (These could be the cause of the brown ooze you see at the intake ports) - cheep insurance.

[RedBaron]

Originally Posted by John_AZ

You bought the '87 944 knowing there was water in the oil.

Replace the oil cooler housing seals. You need a special alignment tool for the OPRV valve or it will bind. The tool costs about $50.

You have coolant in the oil, Porsche says you must replace the rod bearings.
(read bottom). Remove the oil pan and get new rod bearings, rod nuts, oil pan seal.



Have the head machined to check for damage and out of spec tolerances.

Do not scratch the block surfaces when you remove the old gasket.

Keep the lifters/followers in the same order (bore).

Check the lifters for softness by pressing in the piston (stem). If any can be pressed in with little force replace the lifter.

Keep the lifters soaked in oil. There is a tiny hole on the side of a lifter. Keep the hole "UP". Fill the lifter hole with oil from a syringe.

More?? Much more....

GL
John

+1 but I would also...

Replace the valve stem seals and check the valve guides.

Consider changing some (or all) of the radiator hoses while you are in there to prevent them from blowing out and making a mess.

Definitely replace your AOS Seals!

Clean your grounds on the block. They are easy to do with the head removed!

When you drop the oil pan and you try and put the new gasket back on and in place, take your time and be careful with it. I had to go over several times and re-torque them. Clarks has the specific order ( Clark's Garage Home Page ...Very good site if you have never been on it)

A few optional things would be to check the fuel lines in the front, and clean your fuel injectors by either sending them to witch hunter or by DIYing.

EDIT: I don't want to keep posting and bumping threads. To the question below, I know you can get a sort of brown ooze/foam on your oil cap if drive your car short distances constantly. I think it has to do with moisture in the oil, please correct me if I'm wrong. It sounds like bad AOS seals. Just clean it all up, and change them. Problem solved.

[bp944]

I was more curious as to what the brown ooze is. Is it just burnt coolant?

[nota]

antifreeze will burn and water goes to steam
and how does it get on a intake passage anyway

ex gas recirc should be black carbon and oilly
and common build up in the intake

brown = rustsludge or leakstop [ground wallnut shells]
but that should not be in the intake unless long term leak neglected

[bp944]

So you're saying that its due to being run for a long time with coolant in the oil or that it just took a long time to repair. Either way, it sounds like my rods should be completely shot.

[John_AZ]

Rod bearings, and maybe the crank mains.

You will have to pull the oil pan to check.

It is beginning to look like a complete engine ovehaul.

When you get the head off, carefully inspect the cylinder walls. If the coolant was allowed to "pool" on top of the cylinder, it could have ruined the cylinder wall.

Check for scratches on the cylinder wall. ANY that catch your fingernail are bad.

If you are lucky and find no cylinder wall damage move on the the oil pan.

If you have cylinder wall damage you may want to look for a new engine.

GL

John

[Cocacolakidd]

Probably 20% of the 944's out there have some of the oil in their intake system because of the AOS seals - this is more than likely the brown ooze.

Are you positive it's a head gasket - what if it's just the AOS seals - Possible.
As the o'rings/seals shrink and crack from age and when they do they introduce oil from the crankcase into the intake system.

[bp944]

Cylinder heads are off and I want another set of eyes to look at them. Its looking like a definite head gasket but I just want to make sure. Is there any way to clean the cylinder head off well. Can I use rubbing alcohol and I've heard you use a razor to clean the old gasket off. This is my first time putting a wrench to a car so I'm a little over my head. I hate to ask, but what is an AOS seal?






More gasket pictures here: http://s1234.photobucket.com/albums/ff412/bp944/

[Cocacolakidd]

that thingy with the yellow oil fill cap is the "Air Oil Separator". There are two bungs/tits that stick into the block when mounted, and on those are O'rings that seal the emissions into the motor. If or when those seals (O'rings) go bad it introduces crankcase gasses and oil into the intake system.

GM sells a good carbon remover (Valve/head carbon cleaner) that will clean up the head quickly.

Be careful when scraping off the old gasket material so as not to scratch the aluminum - it does scratch easily - then it's more work to correct/remove the scratches.

See the bad spot on the head gasket - good find on the coolant leak. The cyl. with the oil deposits is either a bad ring or two or the AOS seals. If exclusively the AOS seals leaking one would have thought that all cyls. would have been coated in oil deposits - still may be a coin toss as to rings there or the AOS seals.

The pan has to come off for the rings - pita - as the front cross-member and rack comes down also.

Great job so far...

[AA_Ezra]

Aos stands for Air Oil Seperator, it's the entire black bottle looking thing that has the yellow oilmcap were you pour motor oil in, it has 2 seals and the go bad and create vacuum. Loss.
Cleaning the pistons is easy you need
Grease( cheap stuff)
Gasket scraper ( plastic kind at HF)
And crc gasket remover
Just before ur piston hits tdc about 1 inch before put some grease around the whole outside of the piston so no debris will enter. Now make the piston hit tdc now all that grease will keep carbon and junk getting into cylinder rings. When ur done cleaning the piston will then go back down and u can clean up the grease as it makes it's way down kapish?

Now once u get most of the loose gunk off with the plastic scrapers I spray the gasket cleaner I a small cup as it sprays everywhere and then use a brush or pour it on the piston and spread it around come back to it later in a few minutes to make sure it's still wet, if not then add more and after I say 30 min carefully whipe the stuff off and they should be clean repeat untill ur happy with results, any questions let me know. Sry for typos I'm using my phone.

[bp944]

I'm going to scrap/sell this engine in a year about 2,000 miles from now. I'm wanting to do a ls1 swap into it. That in mind, should I replace those piston rings in the bad piston? It seems like a lot of work for very little use.

I also just picked up a set of cam housing bolts for replacing. The only problem is that they are 5mm too short but they are rated at 12.9 rather than the stock 8.8. Would I be okay to attempt to use these since they are the only thing around.

[John_AZ]

Nice work.

The cylinder that looks polished--is the "steam" coolant cleaned cylinder.

When you lift the old HG off the block, remove the coolant between the cylinder walls and the block. In the rear, drivers side corner deep in the bottom is where you will find a silver paste. Remove it. I use a wet/dry vac and suck the coolant out with a tiny hose.

You need new head nuts. You can reuse the washers if you scuff the bottom. The washers cannot move when you torque the head. Mark the washers with paint prior to the 3 step torque. Light oil on the threads.

The head has to be taken to a machine shop. I am sure you will need new valve guides pressed in as well as a standard machine job.

You can check to see if the head needs a standard or thick HG by measuring.
The machine shop should also know after the work is done.



I looked at your photobucket photos and did not see any deep scars in the cylinder walls. You need to check yourself. Again if any catch your fingernail--not good. A single minor scratch may be ignored-usually.

GL
John

[bp944]

What is the silver paste and can I use the mentioned bolts?

[John_AZ]

Silver paste is normal/severe aluminum block engine wear sitting/hiding in a low area.

The torque on the camshaft housing bolts to cylinder head is only 15 ft lbs (20Nm).

The constant pressure on the lifters/followers and the constant rotation of the cam shaft
can cause the aluminum head threads to fail-----not the bolts.

I would not use the 5mm short bolts.
John

[AA_Ezra]

Anybody else notice the Valves were replaced on the head? Correct me if i am wrong but don't i see 1 stock intake valve and 2 that arent?

[bp944]

How clean do you have to make the gasket. I obviously have taken all the chunks off and scrubbed it down with a scotch brite pad. There is some stuff left that almost looks like ink stain that doesn't catch my finger nail.

Also, around two of the studs its clogged with a very nasty smelling something. Should I clear it out and what is it?

[John_AZ]

Originally Posted by AA_Ezra

Anybody else notice the Valves were replaced on the head? Correct me if i am wrong but don't i see 1 stock intake valve and 2 that arent?

You are correct.

An OEM intake and exhaust would look like this...



OR from a couple heads on the shelf..


In a way it could be good news for the OP.

If his head had been rebuilt and replacement valves installed,

the head gasket may be the only replacement needed because it was installed improperly (usual case) or was defective originally--old shelf stock.

The head should still be taken to a machine shop to verify.

But since you plan to replace the engine in the future, Clean up the head as far as you are able to.

Check the head thickness for the correct head gasket.

Properly install the new head gasket---3 step method--30 minutes inbetween each step! Use the old head nuts--why not?

Finish and start it up.

GL
John