Oil in exhaust ports?

[91RSLaserNT]

Ok ive been having some wierd problems on my nt 4g63 where blue smoke comes out of the vicinity of the exhaust manifold. so finally today i take off the manifold to see whats going on and i notice that the number 3 and 4 ports look almost like wet with oil on the inside, but its only on about the first half towards the valve, not down by where the valves seat. What would cause this? is it something to worry about?

 

[ilikespeeding]

Ok ive been having some wierd problems on my nt 4g63 where blue smoke comes out of the vicinity of the exhaust manifold. so finally today i take off the manifold to see whats going on and i notice that the number 3 and 4 ports look almost like wet with oil on the inside, but its only on about the first half towards the valve, not down by where the valves seat. What would cause this? is it something to worry about?

First off, you probably need a new manifold. That would solve anything but the exhaust leak probably. I dont know about the rest.

 

[TwoLiterLaser]

Bad valve seals. Gonna have to take off the valve cover and check it out.

 

[91RSLaserNT]

but wouldnt the valve seals leaking make the valve and the valve seat area oily also? this stuff is only on the outer edge of the port towards the manifold.

 

[FORMONTOYA]

How's the valve cover gasket? If it's leaking it could have dripped in between your leaking manifold and just covered the edge of the port. Does it smoke at idle? I don't mean the condensation "puff" when first fired up in the morning, but smoking at idle. You're right that if the seals are leaking the oil "trail" should go back into the head and not just on the outer edge of the port. Just depends on how long it's been leaking.

However, I would really tend to agree with the above statement that it's the seals. The best way to check is to do a compression check with the valve cover off so you can specifically check the cylinders in question, and the others also. You will probably find the numbers are lower on 3 and 4. You might be able to "feel" the leak past the seals.

 

[91RSLaserNT]

ya, the valve cover gasket was leaking a little bit, but i replaced it and it has stopped now. i would think if the oil was leaking past the gasket that it would have burned off by now, but who knows. i'll do a compression test and take some pics when i get home. O, and it doesnt smoke at idle, just when i rev it or come back after a drive and pop the hood. the manifold itself seems fine but ill be replacing that with a header soon anyways.

 

[TwoLiterLaser]

The oil on the bottom half of the valve COULD be caused by the movement of the valve through the seal. As the valve would come back down after going up into the head it is possible that the excess oil is removed. It also could be oil pressure related such as when you have higher pressure, like when driving, the seals are leaking, allowing oil to enter the exhaust port.

 

[91RSLaserNT]

the oil is not actually on the valve though, the valve itself is clean. its in the port near where it meets with the manifold. it goes about an inch back towards the valve, but not in the actual area where the valve seats

 

[TwoLiterLaser]

My apologies, I misunderstood you, I thought that when you said the first half towards the valve you meant the first half of the valve itself. If there is oil in the manifold itself, then make sure you do not have a leaky dipstick or some other local source of oil that could be getting into the manifold. I do not see how there could be oil in there from after driving as it is very hot, unless the oil is coming in a significant amount. Do a compression test like FORMONTOYA said.

 

[91RSLaserNT]

heres a pic of the ports, i couldnt really get a good shot of the inside of the port, but like i said, its only on the outer edge towards the manifold. i havent gotten around to borrowing a compression tester yet, but i will soon.

 

[FORMONTOYA]

Judging from the picture, which is not the best quality, and your description I would assume that the valve cover was leaking and over time oil seeped its way into the exhaust port.

However, with that said I personally would still do the compression check to verify that it's not just the start of valve stem seals going bad. Even though it's a bit of a labor intensive project, pulling a head and getting it freshened up is not that bad if indeed it's necessary.

If it's proven that the seals are bad and your close to a timing belt job now would be the perfect time to tackle this project.

 

[91RSLaserNT]

Well after some investigation last night, me and a buddy figured out that its not oil at all--its coolant. Guess where its coming from though? the middle stud hole on the bottom row of the studs. We found this out by cranking the engine w/o the fuel pump relay plugged in. You could just see the water trickiling out. I then looked at the gasket, and you could see where the water ran between the two layers of it. Does this mean a new head, or do you think I could fix it somehow?

 

[FORMONTOYA]

Damn, I keep forgetting about that.

There is one stud that goes into the water jacket and if not sealed, it will leak. Just pull the stud, then inspect it. I personally would just get a new one and be done with it, but either way put some thread sealer on the stud and screw it back in. Yours just probably corroded over time and started to leak. It happens (obviously).

 

[91RSLaserNT]

are u serious? it actually goes into the water jacket? whew am i relieved. i thought i had a cracked head or something. thanks for all the help guys and now i dont have to worry so much.

 

[FORMONTOYA]

Yea, pretty silly thing to do, but a fairly common problem. I just sometimes forget about it.

Just make sure to use a hi-temp sealer since it's in the head.