Last night my car started spitting out an awful lot of white smoke from the exhaust. It wasn't constant at first, just a couple of times on the way home from work. When I popped the hood to check it out, I noticed that the oil was a bit low and that the antifreeze had disappeared from the reservoir. The consistency of the oil isn't what I would expect from a blown head gasket though. Its dirty, but not unusually thick.

What are the odds of this being a blown head gasket? Is there anything else that I should be checking for?

DRAIN THE OIL NOW!!!! Either your UIM failed or the LIM gaskets failed.

head gasket? odds are slim to none

NOT a head gasket we have yet to see one fail.....your Upper intake has failed and or the Lower Intake Gaskets also...


DRAIN THE OIL OUT OF THE CAR RIGHT NOW....the longer you wait the more damage you are doing to the Bottom end

Please read this: http://www.bonnevilleclub.com/forum/...e=article&k=38

Then:
Drain the oil
Drain the coolant
Flush the oil system
Order an APN upper kit
Buy GM Aluminum frame LIM gaskets
Buy new coolant elbow(*)
Do not use abrasive gasket remover discs on the LIM or heads; use a good scraper only
Install the rd stovepipe and sleeved upper
Use loctite on the LIM and UIM bolts
Flush the cooling system to get rid of the Dex-Cool
Refill with "mixes with any color" coolant - not Dex
Refill coolant referring to: http://www.bonnevilleclub.com/forum/...=article&k=100
Fill oil , install new filter and run for ten minutes only
Drain oil, change filter, refill with new oil
Watch coolant level carefully

Thanks for the quick replies. My grandfather is on his way over, since I have no tools of my own to speak of.

How long can it sit like this before I have to worry, and how bad could the damage be if I've already waited too long?

The damage occurs when coolant mixes with oil and contacts the sleeve bearings in the engine. The longer the contact-the worse the damage. Worse if you drive the car under those conditions. So, just drain the oil as soon as possible. Also, drain the coolant.

[edit]:
One way to minimize coolant damage to the bearings is to flush the oiling system with fresh oil and a new filter. You must drain the coolant first, however, so that more coolant does not contaminate the fresh oil. After draining the coolant, pull the spark plugs and turn the motor through at least one revolution by hand, then use the starter a few times to remove any coolant that might have filled a cylinder with the piston down. Leave the spark plugs out. Refill the crankcase with wal-mart 5W-30 and replace the filter with a cheap one. With NO COOLANT in the engine, the safest way to flush the system is to turn the engine over with a big 1/2" drill. Buy a cheap, 1/2" drive extension; cut off the female end; grind some flats on it if you like, and chuck it into the drill. You need to remove the RF wheel and splash shield to give you access to the crankshaft bolt that you need to turn the engine this way. You can turn the ignition key to run while you spin the engine with the drill to monitor the oil pressure if you like. By pumping fresh oil through the system as soon as possible, you will minimize any possible bearing damage.

When you have pumped fresh oil for a few minutes this way, you can then drain the oil and remove and change the filter for another cheapo for the next flush you will perform after the repairs are made.

I see above "have yet to see one fail" (head gasket) let me be the first! I had been using a little bit of water for a year or so, could never see where it was going. It may go a month or so, then all of a sudded I was down 2" from the top of the radiator. At 98K...boom, engine stalled. When I tried to start it, it hydrolocked and tore up the starter ring. I had it towed home and I pulled the front plugs. When I cranked it, nothing but water from #1 and #3. Between 98K and 100K I have had 3 engines installed. It runs now, but I still have problems! The rectcler where I bought the engine supplied all 3 engines, he didn't figure out the problem with the oil pressure relief until the 3rd engine, that is what blew #1 ans #2 replacement.

I was told that if you overheated a 3800 even once, you were destined for a blown head gasket. I lost a water pump twice in this thing...and of course an alternator with each water pump. I was lead to believe that it was just par for the course.

Overheating 3800'* doesn't increase your chances of blowing head gaskets. At least not in our 7000 member collective experience. They are cast iron heads and are very durable.

You are a rare case. I think your head gasket failure was a side-effect of a bad engine build from your source. Let'* try to keep this topic on track though, and maybe continue your issue in a topic of it'* own if you'd like.