Viper

iTrader: (6)

Pulled my TB today, noticed a light brown sludge on the back of the TB, and in the intake. It's coming from the tube off the passenger valve cover. Obviously it's oil, but what's in the oil? Pulled my dipstick, there's brown sludge on the dipstick and bubbles in the oil. Haven't pulled a valve cover yet. Other things; I have a post in the PCM section regarding 2 SES codes; low voltage on both rear O2's. I don't have cats, and those codes were deleted in February. On the way home today the car stumbled at low RPM, but once I was on the highway I goosed it and it was fine. Also, can you plug off the hose coming off the valve cover to TB? I'm also running dino oil, and planned on going synthetic this week.

digitalSniper

Is it possible that you're getting coolant in your oil. Sounds like a crack in a head or a block if that's the case. Hope it's not, but sounds kind of like it.

Viper

iTrader: (6)

I suspected that as well. Will a pressure test show that? I had a coolant leak back in March, it was a bolt loose on the waterpump. Then twice since then I've had to add a little coolant. I'm thinking the 'sludge' hitting the TB blade is causing me some havoc in high idle speed and stumbling.

Viper

iTrader: (6)

I just put a picture up of it on my web site:

http://junior.apk.net/~viper/pics.htm

Last picture. Sorry about the quality.

digitalSniper

I'll give you my 2 cents worth on this, but solicit more info from others as well, as I'm new to this engine. I'd have that oil looked at in a hurry, and I'd avoid driving the car until it's checked out. If you've recently changed the oil, and your car has been well maintained throughout its life, your new oil should remain clear for sometime after the change. I only know of one thing that can cause oil to look as you described, and that's when it's mixed with coolant. Where you want to get help from others is how it's getting in. Hate to say it, but the only way I know of is a crack in the block or head.

DaleMX

iTrader: (4)

If it's coolant you might be able to smell it on the dipstick.

Viper

iTrader: (6)

I'm going to do a pressure test tomorrow as well as an HC CO test on the coolant. Plus change the oil and inspect it.

Viper

iTrader: (6)

Car stumbled this morning until warm, then it was fine. Did my first WOT blast since getting the new clutch, felt fantastic. I manually cleared the code this morning, I'll see if it shows back up.
Has anyone else seen what is on my TB in the picture? Another theory is I'm not letting the car warm up enough, and it's just what oil does if it's not heated all the way. Thoughts?

Any other ideas between now and tonight when I begin testing will help. Thanks in advance.

crewdawg16

Change your oil and look for the coolant to come out first, it will be on the bottom of the pan and will come out before the oil, if it is mixed in it will be off-color and foamy. DO NOT plug up the PCV line going to the TB, your crankcase releives pressure through that line you are talking about, that is why you are getting oil up there in the first place. GM engines are notorious for getting oil in the intake from the PCV setup. It is hard to tell from the picture, but that looks like fresh oil to me. Once you change it, you will know if you have coolant in it.

crewdawg16

If you want help stop the oil from getting up there in the first place, the LS6 has a much better setup than the LS1, also, you can add a catch can for that oil in-line to stop it from reaching the TB. Here's a link for the LS6 PCV Valley Mod. Also, besides a cracked block or head, it could just be a head gasket if it is coolant in your oil *crosses fingers*. http://www.ls1howto.com/index.php?article=18

Viper

iTrader: (6)

I did the vertical PCV mod, and that stopped oil from getting to the TB through the intake. However, this is the live that goes directly from the valve cover to the TB at the top; I thought it was for fresh air and that the PCV was the issue with oil getting in. Am I missing something? In this picture:

http://www.ls1howto.com/howto/ls6pcv..._installed.jpg

It's the hose from the valve cover to the TB. So even if I did the full LS6 PCV setup, I'd still have this issue.

Tin Indian

That moisture in the TB is coming from the crankcase via the PCV system. I would be willing to bet your oil looks like a chocolate milkshake.

If so, you have either a blown head gasket or a cracked head. I really doubt your block is cracked. My money is on a blown head gasket.

Now, what would normally cause a blown head gasket in a low miles engine?

1. Improperly installed head gasket after a head change

2. Detonation when too much NOS is used

3. Detonation when too much boost is used

Any of these apply in your case?

crewdawg16

Aahhh, yes that's what that is. It is the air line. Sorry, misunderstood what you were saying. I would guess that your engine is just slinging oil up there at upper rpms, but I've never seen anybody post about this line getting oil up in the TB before. Never really understood what that line was for, I would imagine you could plug it if you wanted, but the real scary part right now is that you think you have coolant in the oil. If that proves to be false, then I would ask around some more, and plug that baby. What weight oil are you running?

Viper

iTrader: (6)

Yes, oil looks like a chocolate milkshake. I've lost small amounts of coolant in 6K miles since the new motor went in. Block was redone as were the heads. I'm hoping it's just a head gasket.

Tin Indian:

1. - don't know - driving to Jersey for a dyno tune, will have the engine builder look at it ahead of time.

2 and 3. - nope, N/A here.

Crewdawg16 - 4 10w30, 2 15w50, dino oil.

Plan on changing to 10w30 x 6 synthetic tonight.

OK, so if the head gasket is blown, should I not bother changing the oil or driving it? I'm in a catch-22 ; have to get to Jersey to fix it. Would a blown head gasket give me the symptoms I describe above? Like stumbling? Can I plug this air line for the 500 mile drive out to Jersey?

crewdawg16

Depending on HOW the gasket is cracked, yes the coolant getting into the cylinder would definitely affect that cylinders' ability to fire correctly, especially when cold. You say that it stumbles when cold, then drives fine. If the crack were between two cylinders, you would get a real lack of power and stumbling as they would be cross-firing. The oil sounds alright, I don't know much of mixing different oils together, but I don't see a problem with it. Is the dino oil synthetic? If it is, you should never mix the two, if not, excuse my ignorance.

crewdawg16

It was just brought to my attention what that line is for. Ok, so your PCV has air sucked out to depressurize the block right? This line is supposed to provide air INTO the block to avoid a vacuum. (If you look at hot rod engines, many times they will have a breather here with a filter on it.) So, you should NOT plug this line either, but more importantly, you should definitely NOT be getting oil coming up through it since it should be sucking air the other direction. Check your PCV valve and/or line for a clog or something. Maybe this will solve your problem.

Viper

iTrader: (6)

OK, now it just got interesting. If that is supposed to be air going from the TB 'TO' the valve cover, it is very concerning seeing a foamy light brown paste going through. I'll check the PCV and all lines for blockages. And change the oil and look for foam when it comes out.

The 2 15w50 and 4 10w30 is something Patman ( LS1Tech reident oil expert ) had people doing; a way to get a heavier weight oil.

If anyone has suggestions on what oil to run, please, tell me. Forged engine, 10.7:1 compression.

crewdawg16

Yes, this is interesting And there is nothing wrong with mixing different weights of oil, just not organic and synthetic types, they dont mesh well . Good luck on your finds.

Viper

iTrader: (6)

OK, now I need to figure out how oil can blow the other way through this fresh air tube. Anyone?

crewdawg16

That's why you should check your PCV line and valve, if you were to have a blockage in there, or if the valve is bad, the pressure created by your crankcase would have to go through that line instead, hence the oil coming up through there.