Malibu oil change drama

[kevm14]

Yesterday I changed the oil on both the Malibu and my Caprice. I did the Caprice first. It went fine.

Onto the Malibu. I decided to drive it around the neighborhood to warm up the oil. I had driven no more than a mile or so and the engine was almost fully warmed up. Quicker than I remember. Then I realized there was no heat. Uh oh. Drove back home and the temp started creeping up above halfway. Shut it down.

Incidentally, several months back I ordered a new coolant pressure tank cap because the original one was beyond failed and requires prying with a screwdriver to remove. I finally get it out (and it disassembled in front of me as I did) and realize the tank is low on coolant. Ok...

I had some Dexcool so I make up a 50/50 mix and begin to add it to the tank. It ended up taking a 1/2 gallon. And the heat came back. But where did the coolant go? I checked the oil and it looked like it was WAY up the dipstick. I immediately began to freak out since I figured it was eating intake gaskets, something these 3.1Ls were known for but I've never had to deal with that issue. I reinserted the dipstick figuring maybe the oil splashed up from all the engine revving I was doing to get the coolant flowing. After checking it several more times, the level actually appeared normal (in the crosshatch).

Then I did the rest of the oil change which went fine, and the heat works great now. But I still don't know where that coolant went. No signs. I should also point out that I've never known this car to use coolant, ever, except when the water pump let go a few years back. I'll have to keep my eye on it. 136k.

[bill25]

Could it be the head gasket? I heard that if that is what is happening, there would be white buildup on the spark plugs.

I am far from a mechanic, but that might be worth looking in to.

[bill25]

Also, from what I have read, if this is what is happening, you need to fix it immediately because it prevents the oil from lubing the engine properly, and the engine will be destroyed very quickly in this situation.

Another symptom is sweet smelling, milky looking oil.

[kevm14]

After rechecking the level, I realized the oil level wasn't high. So I don't think the coolant is going into the crankcase. No white smoke out of the exhaust either.

I also examined the radiator end tanks and I didn't see leaks there, either. We'll see how long it takes to leak.