I'm afraid my X is going to detonate.

[dkime3]

So I was at the gas station waiting in line for the pump and all of a sudden there's white smoke coming from the engine bay. So shut the car off immediately and check the Coolant resevoir for the coolant level and notice that the RED BOBBER THINGY is GONE. WTF? where the hell did it go?!?! So I put some coolant in it and pump gas and all is well. Nothing on the display everything is good. So I drive to go get something to eat and as I'm driving the Check coolant level comes up on the display. Now I'm thinking WTF?!?! I just put coolant in there!!!! Then it changes to COOLANT TEMPERATURE and the temperature gauge goes to PAST RED at the speed of MACH HOLYSHIT. So I park at the hamburger joint and pop the hood and there's a CRACK in the COOLANT RESEVOIR and it's spewing coolant out. WTF?!?! It's all over the parking lot. So I need a quick fix and luckily there's a AUTOZONE about 50 feet from where I was intending to eat and I walked over picked up some coolant some crap to fix the crack with and went back to the car to drive home to fix the damn thing.

Waited until the everything cooled down. Put that rubber cement looking thing on the crack to patch up the crack and then filled it up with coolant to the best of my ability because somehow the MEASUREMENT STICK in the COOLANT RESEVOIR disappeared. After that just left the car alone for a few hours so the crap i put on the crack could fully dry then drove home. On my way home the temperature needle screams to red again and "coolant temperature" light comes one again. Now I'm thinking WTF?! what now. Nothing seams wrong. The crap I put on there to fix the crack is rock hard and holding fine. There's no smoke coming from the vehicle at all but still the temp. needle is at PAST red. So now I'm dumbstruck and have NO idea WHAT TO DO. It's Saturday night and I HATE to take this thing to the STEALER tomorrow cuz it's a 2003 3.0 X5 and it's WAY past warranty. I just recently plopped down about 3000 in parts and labor at the beginning of MAY to have all sorts of crap fixed.

Anyone have a clue on what the problem might be and how I would go about fixing it? ALL SUGGESTIONS WILL BE GREATLY APPRECIATED!!!

[Aimster]

Are your hoses fine?

[dkime3]

I think the hoses a fine. I'm not sure though. How would I go about checking this?

[we350z]

so did you over heat the engine or not? because that is pretty bad if you did, I would not continue to drive the car like this. Maybe you just have a bad thermostat? Is it hot where you are? My '85 Z's coolant reservoir exploded all over my windshield and then thick white smoke shot through my vents on my way to vegas several years ago. That really sucked, I was all worried I f'ed the engine since it overheated. The stealership removed the valve covers and inspected the head and everything was cool according to them.

[asawadude]

If your coolant tank crack was large enough to allow coolant to spill onto your engine (hence the white smoke), then it's quite likely that the system was completely drained of coolant. Not only was your coolant tank empty, but so was your radiator. Unfortunately, newer Bimmers don't have radiator caps for a direct fill. You have to fill the coolant tank, replace the cap, run your engine until it reaches normal operating temp, shut it off, then check the coolant tank level again and repeat until the tank is full. You only did it once - that wasn't enough.

I lived with a cracked reservoir for over 6 months, so I went through with this routine of having to fill and refill my reservoir every 1-2 weeks.

While you're at it, check for leaks around the radiator, the top and botom hoses, and check the condition of the belts. Are the radiator and auxilary fans operational?

If you continue to have an overheating problem, I'd park it and have it towed to the dealer unless you want to risk a destroyed engine.

If it doesn't overheat, but continues to lose coolant, then you need to get the cooling system pressure checked.

[Zulu95]

Water pump?

[Hal88]

Get a new coolant reservoir, they are not expensive and they are easy to change.

[X5HogTown]

Sounds familiar. Just happened to my 01. A 4" vertical split in the expansion / reservoir tank. While limping to the shop, it would run cool off the highway. It would immediately go into the red on the highway. The part cost C$130.

I think this tank is pressurized so sealing the crack will be futile.

[Estroil 4.8is]

Also make sure you bleed the system correctly and fully. You have to reinstall the cap and run the engine while cracking the bleeder screw next to the fill cap. Keep cracking it open until there is only fluid coming out and not air bubbles. GL