I realize this has been beaten to death- but I could not find any real definate guidelines or info on diagnosing the "coolant in oil" issue on the 3100.
I'm in process of tearing the LIM off now.

Is there a definate guideline on determining if it is JUST the LIM, or the Head Gasket as well?

It's really cold out, as I can only work on this outside and do not want to do the headgaskets if I don't need to.

Thanks!!!!

I assume you already started taking it apart. Run a compression test. If compression is in normal range, then your headgasket doesn't leak. Also check your plugs for coolant residue and the orange, green color (or whatever color you are currently using now) of antifreeze on them.

99.9999999999999% of these 3100's that have coolant in the oil are intakes only. im not going to say head gaskets are impossible, but from waht ive seen mostly when 3100 / 3400 head gaskets go, that havent been run hot, leak into the cylinder and smoke terribly. feel confident in doing the intakes only. oh, and make sure u torque the bolts to spec. and tighten the long center bolts first, with plenty of loctite on the threads

What are you using for replacement gaskets ?

Dorman and Felpro have an upgrade gasket set.

The Dorman set includes metal gaskets with rubber on the port openings, new intake bolts, valve cover gaskets, etc.

Yes, that looks like the case.....LIM gasket only.
I did a compression check. Engine has not been run in a while, and it was about 25 degrees F ambient temp.
The LIM was already pulled off, so the intake ports were wide open.
Compression on 2,4,6 all showed around 116LBS.
Compression on 1 showed around 110, 3 showed around 80 and 5 showed around 90.
I went ahead and pulled the heads anyways, and the gaskets showed no signs of failure. The 1,3,5 head was fine, the only thing I seen was the fire-ring on the 3 cylinder looked like it wasn't sealing real good (a very small dark area around the fire ring witness mark).
Cost of new head and exhaust gaskets, bolts, and machine shop clean-up resurface was around $150. Probably could have just left them alone.
Anyways, it's all back together and running.

Now, I have wet carpet and have to chase a heater core leak!! (I hate working on cars in winter) :banghead:

Oh yes, I used all FelPro gaskets - what they call 2nd design - steel with rubber lined inserts