I was driving on freeway when I noticed car was sluggish and seemed like it was running out of gas. Car never overheated or gave me a check engine light. I made it off freeway and got it towed home. Told a friend about what had happened and he came over and noticed water in oil. he suggested from experience that the upper intake gasket was cracked. When he removed gasket there was water and sludge intake. He replaced gasket. I drained oil and added new oil. When I started car it threw a lot of white smoke or vapor. It doesn't do that anymore but it runs as though it is missing. I opened hood and noticed that the radiator hose was sucked in as though air was squishing it together. Oil is milky too. Don't know if it is because of the junk that still might be in the engine. There is no knocking noise in the engine. Car is 2003 Monte Carlo SS.

 

You probably need to change both the upper and lower intake gaskets..(common on the 3.8's)
I would change the oil not once but twice..before id consider trying to drive it...Maybe let it run a minimum of 10 mins or completely warm up.
before id change it the second time...

I would also highly recommend a complete radiator flush to un contaminate the cooling system...Completely! and besure once your sure its flushed clean...To use the proper mix of water and antifreeze. also besure the cooling system is free of any airpockets for proper cooling....Do Not use all antifreeze ever... It only compromises the cooling system causeing it to fail prematurely...

The collapseing of the radioator hose is due to the failed gaskets....

 

Why is the radiator hose being crimped as though its struggling to circulate water? I notice the smell of gas from exhaust pipes. Don't know if it was when gasket went. Or if its from residue from water in the engine.

 

Like I said in the last post you have a failed intake gasket...so the water is getting into the oil due to the water jacket being compromised by the gasket allowing it to leak into the oil...thus createing a vacuum...and sucking it into the motor..where its not suppose to go...You may even end up replaceing the manifold itsself as it is made of plastic...andmay also be warped out of shape....

You may want to check out other past posts on here that will better explain what happened and how to repair it...
as well as what brand of manifold, gaskets etc...to use to fix it properly..

Or quite someone else may chime in and add other ideas on how to resolve your problem...

Heres some ADDITIONAL INFO THAT MAYBE HELPFUL:

Service Issues
One of the reasons why the 3800 has had such a long production run is that it has been a very reliable, trouble-free engine for the most part. Many of these engines have racked up well over 200,000 miles with normal maintenance.
One of the few trouble spots has been coolant leaks on the Series II 3800 engines with the plastic intake manifold. The OEM intake manifold gasket tends to deteriorate after 60,000 or so miles in the area that seals the cylinder head coolant passage to the manifold. The seepage of coolant past the leaky gasket leads to overheating, and may cause bearing damage if coolant leaks down into the lifter valley and gets into the crankcase. The fix is to replace the OEM gasket with an improved aftermarket gasket, or the revised OEM gasket (P/N 89017554) per GM bulletin 04-06-01-017 issued in May, 2004.
The coolant leakage problem has been blamed on a number of factors, including coolant neglect and a less-than-robust OEM intake manifold gasket design. Though Dex-Cool is supposed to last up to five years or 150,000 miles, some say changing the coolant every two years can avert many of the problems that occur with aging coolant. Also, if the coolant level gets low, oxygen mixes with the coolant, which tends to cause problems with Dex-Cool.
On these engines, it’s not a bad idea to add a bottle of cooling system sealer to the cooling system for preventive maintenance, whether the coolant needs changing or not. The sealer will circulate with the coolant and hopefully stop any small seepage leaks in the intake manifold gasket from getting any worse, at least for a while. This may save your customer the expense of having to replace the intake manifold gasket. If the gasket is already leaking, sealer may plug it up temporarily. But, eventually, the gasket will have to be changed.
Another coolant leak problem prompted GM to issue a recall on certain 2000-’03 model year Chevys, Buicks and Pontiacs with the 3800 engine. The coolant leak on these engines was at the gasket between the intake manifold and throttle body or, in some cases, between the upper and lower intake manifold. The recall involved replacing the three throttle body fasteners, applying sealer to the threads, and dumping some sealer pellets into the cooling system reservoir. Recall 03034 was issued in July, 2003, but was only good until July, 2004. If a vehicle was repaired under this recall, there should be a GM recall decal affixed to the engine or under the hood.

 

When talking water/coolant in the oil on a 3800 L36, it's normally one of the following:
- Lower Intake Gasket (normally the culprit)
- Upper Intake Gasket
- Upper Intake (where the stove pipe is for the EGR will burn a hole allowing coolant that feeds the throttle body to seep into the UIM and dump into the engine with your air flow, thus white smoke out the exhaust).

In your case you have white smoke, could be a head gasket (but that's less common). My guess, your upper intake is failed. Your fixes are:
- 1 - Replace the UIM with another plastic one (APN makes the best one)
- 2 - Replace with a L26 Series 3 aluminum upper intake (some extra work is involved, if you want to go that road, I happen to have a L26 aluminum UIM for sale, we can discuss the issue further).
- 3 - Take the UIM off, tap and plug the ports in the LIM that run coolant to the throttle body (for added security, I'd fill those ports on the UIM with JB Weld).

#3 is your CHEAPEST method. I did it to my Monte (as I just did not want to warm the incoming air), I know some one else that did it to a Grand Prix to save a couple bucks (working fine, no issues). You can buy the plugs are Home Depot or any other hardware store. In case, I also put JB Weld on the threads of the plugs.

Here's a pic of what the LIM would look like:

Here's a link to more info about this:
'04 Monte Carlo SS - Port Matched LIM

I also recommend, since you are halfway to the LIM, do those gaskets too, replace with the aluminum FelPro gaskets (if the upper gasket failed, I can bet you the lower is not far behind).

As long as you're NOT continuing to run the engine with the white smoke issue, it is possible to bounce back from this problem.

BTW - I don't believe any of the crap about Dex cool as long as you're talking Dex used in the late 90's. GM revised the formula, continue to use it today and to top it off, I've had nylon gaskets on cars that never had a drop of Dex fail the same way Dex supposedly eats gaskets. The reason the gasket fail is that nylon was a garbage material from the beginning.