Drive it and then check the dipstick. If water is in it, the oil will look like a chocolate milkshake.
Most shops have ways to test whether there is a blown head gasket.
I would go and say that it is water ingress due to rain and dipstick being loose.
However just to make sure do a full oil change and replace your coolant at the same time. I am sure you know what to look for when you drain the old oil and coolants, but just in case - look for excessive presence of water in the oil and for traces of oil in the coolant.
After changing both keep an eye on both as it will become very obvious very quickly if the head gasket is truly gone.
Water in the oil turns the oil white. This could be just in the dipstick tube. I have seen this happen just from condensation on the inside of the tube. An inexpensive test would be to drain the oil and see if you actually have water in the crankcase. Remove the spark plugs and see if there are signs of water on them.
I think so. Change oil and filter. No white smoke in exhaust? No bubbles in coolant (look in radiator with engine warm and running)? Don't take rad cap off when hot, you might get scalding coolant in your face! Probably just from the rain.
It could have gotten in there through the dipstick but while driving with dipstick out, oil will spray out of the dipstick and soak engine compartment.
It will just cause sludge. Next oil change will need flush to remove the sludge if there is a lot.
An inexpensive 8cooling system pressure test will find any external or internal coolant leaks. IF an internal leak is found, a cylinder leak-down test will show exactly where the leak is.
do your self a favor and take it in to the dealer for the issue. GM used "dexcool" from 1996 until recently. it created issues like this as i understand it die to gaskets failing, some how.
2006 Chevy Cobalt 2.2L discovered dipstick loose and water in oil after driving in rain all week. Water in oil that's not getting worse, not losing antifreeze, and no smoke from exhaust. So is the head gasket blown or did I get water in the oil from driving in the rain all week with the dipstick out?
