Coolant hose blew, system building pressure?
 

So today I was driving on the freeway and the "check coolant level" light came on, a few seconds later steam everywhere, I pulled over and checked under hood and the coolant hose in front that goes from the water pump to the res tank had blown off, I pushed the hose back on and hobbled off the freeway and "pow" it blew off again shortly. I then pushed the hose back on and found a hose and added some water then continued down the road in an attempt to get to a auto parts store, It blew again with another loud "boom".

I then set off on foot and found a gas station, bought some hose clamps and coolant (they actually had BMW coolant). I removed the old compression fitting off the hose, attached a hose clamp and filled her up. A couple miles later "boom" it blew again.

Something is causing it to build up enough pressure to blow the hose and get hot. Could it be the water pump? a clog in the cooling system?

I really hope the "boom" wasnt the head gasket blowing as it did get into the red a couple times. Any advise?

Thanks

Shouldn't the vent on the expansion tank work before the cooling system reaches enough pressure to blow a hose off?

Hopefully it's not cylinder pressure getting past the head gasket.

I hope not, but the motor seems to run just fine, just gets hot and blows the hose/coolant. I did replacde the radiator and expansion tank about a year ago. Not sure about the water pump on these cars but usually in other cars when there gone you can hear it. Im totally stumped!

anyone have any ideas on this? I could use some advise before I begin to try to find out whats wrong. Its raining so im going to have to wait a bit to get started (no garage)...

What is the age of the blown hose? If it's old, it might just be worned out seal/connector.

Try replacing the hose, and use OEM hose.

Double check to make sure the connector is pushed all the way up against the thermostat/WP, and the metal locking clip should lock inside the indentation ring around the thermostat/WP. It takes a little force to get the connector on properly.

The cooling system does build up pretty good pressure.

Good Luck.

thanks, The hose is old but maybe I need to clear things up a bit, the hose itself didnt rupture it has blown off the connector, I installed a regular hose clamp and it blew too, after the motor got hot into the red, I guess I need to pull the water pump and check it, car has 140k on it and as far as I know the WP has never been replaced.

I had the same thing happen to me 2 weeks ago. It had been extremely cold for a couple of days and I took it out, when I parked a few seconds later, it blew and steam was coming out. I looked around and the hose had just come off the clamp, I was able to replace it that same day, I did'nt think it about the water pump though :(......The cooling system has been a nightmare for me.

Is the fact that the hose just came off the clamp a real problem or just a sign of age??

BMW engine runs hot so the cooling component becomes the achilles heel.
If you park outside (not garage), live in extreme climate etc I'll say it's time to replace hoses. I garaged my X5, and the upper radiator hose crack; well my X5 is 8 year old so I guess it can happen. Though the rest of the hoses look good but decided to replace them all. As well as WP and thermostat, then I realized the creaking sound at start up that lasted 20sec or so actually came from WP bearing so I was lucky that thing didn't seize on the freeway.

Sometimes, count your blessing if your car just give you "gentle" reminder it's time for repair. I would rather see a crack in the coolant hose than stuck-closed thermo or blown WP on the freeway.

You should replace the hose and make sure you bleed the coolant. A reason why it could be blowing off is because there is air stuck in the sytem and it is causing air pressure to build up. Another problem could be that your thermostat is stuck closed. Your car should never heat to the red.

www.e38.org for bleeding tips.