Engine overheated, now it doesn't idle as smoothly

[Fried_Chicken]

So my expansion tank for whatever reason came loose and hit the accessory belt, causing it to grind a hole on the side.
Coolant exploded out, and the car overheated.

As soon as I noticed this, I turned off the engine and got it towed home by AAA.

Unfortunately I think some engine damage might have occurred, the car doesn't idle as smoothly, and it makes a new noise, a fast tssk tssk tssk when listening from the outside.

Performance seems unaffected, and I don't think any major damage has occurred, but it does have me a little bit worried.
Does anyone have any experience with overheated engines? Is this something that I can fix easily, or is it a head gasket or something?

I think the noise is coming from the intake area, but I can't be 100% sure.

[BCS_ZHP]

Pull your dipstick and check your oil - does it look milky (water mixed with oil)? What's the level (may be above full of water got into the oil)? Look in your radiator (when cold), has oil mixed with your coolant?

[Johnmadd]

Pull your dipstick and check your oil - does it look milky (water mixed with oil)? What's the level (may be above full of water got into the oil)? Look in your radiator (when cold), has oil mixed with your coolant?

+1

Also, maybe you just burnt the oil and it lost its viscosity.
I recently worked on a m50 that needed a head gasket and the oil was milky, turned out the gasket was good and the head had an internal Crack in the head.

[Fried_Chicken]

+1

Also, maybe you just burnt the oil and it lost its viscosity.
I recently worked on a m50 that needed a head gasket and the oil was milky, turned out the gasket was good and the head had an internal Crack in the head.

Oh god please don't say things like that

[az3579]

Oh god please don't say things like that

There really aren't any ways to sugar coat it, man... sorry to hear this happened.
Get a proper diagnosis and let us know what the deal is. Hoping it's something minor.

[Fried_Chicken]

I'll see what an oil change does.
It still drives fine, has the power it needs, and the vibration and noise is only noticeable because I'm so intimately familiar with the car.
I'll monitor the coolant level. It really is an oversight for BMW to not have proper overheating warnings.