Losing coolant and oil

Unfortunately for me, I think it's a blown head gasket, but here's my symptoms.

'98 3.8 Manual Camaro 195k miles

- I lose oil fast enough to have to add a quart every month.

- I lose coolant fast enough to have to add between a half and a full gallon every few weeks (Dexcool).

- There is a white sludge type material under my oil cap, but the oil itself does not look milky.

- Sometimes my car knocks when I start it in the cold weather, but the knocking goes away when the engine heats up.

- Sometimes when I start my car it has white smoke coming from the back, but this is only in the cold weather and the smoke stops when the engine heats up.

- If I open the radiator with the engine running, I see some bubbles and the coolant will overflow when it starts to get hot.

-At my friend's shop, a device was placed on the open radiator as my car was running to test for fumes he said would indicate a blown head gasket. The color did not change and no fumes were detected.

I am afraid it is probably a blown head gasket, but I am not positive because it didn't "fail the test" and the smoke/knocking is only in cold weather. Plus the oil looks normal.

If it's not a blown head gasket, I can't think of what else would cause me to lose all the oil and coolant I am losing.

Any thoughts?

intake manifold gaskets are a common issue with the 3.8. I'm unsure if this would effect the oil loss, but with that many miles, you may have more than one problem on your hands.