Second opinion on head gasket issue?

[E39525i2002]

I checking the coolant regularly after having an issue where the expansion bottle had an invisible split in the side a couple of years ago.


When I initially opened the expansion cap this time, I got an up-swell (fountain) of coolant coming out of the system for a moment. The coolant wasn't very hot at that stage. I think this is one of the typical signs of the head-gasket - gasses trapped causing the liquid to surge out.


The usual circulation of coolant wasn't happening either - that was typical of when it had the split in the expansion bottle previously, allowing air into the system.


I tried to bleed it out but it seemed to be a whole lot of air - or exhaust gasses? - trapped in there. This video is just 20 seconds of bleeding, but I had the screws open for over 5 minutes without the bubbles going completely: https://www.youtube.com/watch?v=IRztfduhQSY


Local mechanic said it's almost certainly head gasket, but wasn't 100% committal on it.


Are these symptoms guaranteed to be a failing head gasket? I don't want to pay for expensive diagnosis if the car is a write-off, but I don't want to write-off a good car if it could just be a failure somewhere in the cooling system.

[RuskiE39]

Is there a mix of oil in coolant and vice versa? Drain your oil and find out... shouldn't be that hard, you can also just check your dipstick.

[nikh23]

Check compression in the cylinders


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[MIKYZZ4]

Remove exp-tank cap and top off coolant,
perform a leakdown test on all cylinders,
while observing topped off coolant for air bubbles.

- - - Updated - - -

Now you have 100% confirmation.

[Ed CT]

You can pick up a test kit at auto parts stores for detecting exhaust gases in the coolant. It's a liquid that turns a different color when there's hydrocarbons in your coolant. If you don't have oil in your coolant, or coolant in your oil, this will detect the third possibility. Also, a huge cloud of white fog out of the exhaust at startup is also a sign. Or, in extreme HG breaches, hydro-lock from coolant in the cylinder(s).

[m735is]

Does the car over heat?
What are the temps getting to when you use the cluster to check?

What happens when you bleed it using the method with the car not running?

[Mach540]

What I would do is get a real big balloon and put it over the expansion tank. Start the car up and see if it fills up. If it does, once it is big enough, take it off and breathe it in for a while. If you get light headed and pass out, it's probably exhaust.

But the exhaust detection kit available at an auto parts store is a better idea.......

[geargrinder]

LOL. Sweet diagnostic idea.

Reminds me of when I was a kid and my (jerk) 'friend' wanted to test the ignition on a junk snowmobile, he handed me the ignition wire and didn't say anything but "hold this". Then yanked the starter cord.

Ignition still worked very well.

[Mach540]

Yeah, stupid breathing it in idea aside, a balloon is an definitive way to differentiate whether you are seeing bubbles just working their way thru the system, or if the system is producing the bubbles via a bad head gasket.

[MIKYZZ4]

Enter last 7 digits of your VIN# here:http://www.realoem.com/bmw/enUS/select

[Wolfen]

Check Amazon. They have all the kits and will be at your door the next day.