docwyte

You don't want scored cylinders. That's how I ended up with an LS1 in my car...

CO951

Well, I picked up that recommended combustion leak detector. I did the test according to the directions and there was no change in the fluid color. This indicates there are no combustion gases in the coolant system. Does that completely rule out the HG?

ehall

See above. That oil issue is a big deal...BIGGER than a HG!

MooreBoost

Still think you should do a coolant pressure test

ehall

Couldn't hurt.

CO951

I did the coolant system pressure test and it didn't lose any pressure at 15 psi, so I did it again at 20 psi and it still didn't lose any pressure over 15 min.

ehall

Did you figure out why you are seeing such low oil pressure at hot idle?

CO951

The oil pressure issue I saw looks like it may be an issue with the gauge/sender it now reads 1 on the gauge all the time, even it the engine isn't running, if the key is on.)

ehall

Well, with your smoke issue, I would replace the oil sending switch ASAP. Buy one of the decent ones, not the super cheap one.
Yes, it could just be the wires, but most likely it's not. When they go they go. Also, how do you know that the gage isn't actually reading the correct number?

CO951

I assume the gauge is the issue, since I just replaced the sensor with a cheap one a couple weeks before the problem occured, but more importantly it shows a pressure of 1 when the engine is NOT running and it should be 0 when it isn't running! I have not lost significant oil in the time since the problem started and I definately didn't have an oil pressure loss when the problem started, because I've watched very carefully since then and it didn't start until about the 4th time I started the car for testing. I do agree that I need to replace the sender before I go any further, just to make sure the oil pressure isn't a problem.
With that said does the testing I've done eliminate the HG? (Not to say I shouldn't put the HG on my short list of things to do on the car.) If the oil pressure isn't a problem (as I believe but will confirm before going further), what would be the next thing? As a reminder, the smoke started suddenly under full boost, it won't build full boost anymore. I have a small oil leak from the back of the cam tower gasket that drips on the exhaust and the smoke out the exhaust doesn't start, when the engine is cold, until about the same time the smoke starts from the leak.

ehall

Actually, before you replace the sender, flip the wires and see if it works properly. If not then yeah, replace it.

ehall

I would say that the HG is still in play. The one thing that the test won't always catch is a semi-blown HG like a few of us here have experienced. It shows up best when the engine is hot and trying to boost. It's tough to do the coolant pressure test on a hot engine, so it's hard to diagnose, but my money is still on the hg.

CO951

The oil pressure gauge had worked properly for a couple weeks after replacing the sender, so I know the wires aren't connected wrong. I will replace the sensor.
Just to get it straight, from my understanding of everything I've read, at this point the only symptom of a failed HG is that I have is the white/light gray smoke that starts after about a minute on a cold start. You may be right about the HG, but is there anything else that could be causing the problem that I can test/check before I tear the head off? For example is there a way to check the seals in the turbo? Do you just check for play in it?
Thank again for your help!s

ehall

I can't think of anything else to check without taking the aforementioned assemblies apart. Be it turbo, oil cooler, HG. etc., the only real way to check them is to tale them off and tear them apart.