My BMW 325xi that I recently purchased is not running well. If anybody has any clues based on the below symptoms, I would really appreciate it!
-Coolant level decreases
-Pressure stays in the radiator even when the engine is cool
-The car is driveable (I've driven probably 200+ miles after purchase before the Check Engine light came on)
-The car still drives, but performance is obviously lacking: It stalled once, I put it in Park, then restarted the engine, it ran smoothly until I reached my destination. Another time, the RPMs went up to 5k+ and stayed there, I shifted to Neutral and they decreased, once I went back to drive it was like normal.
-The air conditioner works perfectly fine
-When I first start the car up, it seems to studder a little bit, then drives pretty well.
-I've been repeatedly filling the coolant reservoir, and it always seems to empty after a trip, but never overheats.
-The engine temperature gauge starts cool, then heats up to halfway between the blue and red and stays there, never gets too hot.
-There is no white smoke from the exhaust, no smoke from the engine
I took the car to a mechanic that I've never used before (first time owning a BMW). They said the cylindars were misfiring and went through a few different tests, including putting blue liquid somewhere. They didn't tell me the color it came out, but he said it failed that test (which he told me means the liquid is mixing with carbon monoxide). He recommended I have the head cylindar sent out to be tested to see if the cylindar was cracked or to diagnose a head gasket problem. He estimated the cost to be $2500 best case scenario, possibly worse if the cylindar is cracked. Any help would be amazing!