2000 328CI - Radiator Hose Blew Off at Correct Temperature

[Bishopfolds]

I was driving at normal cruising of speed of about 45 mph when a heard a whine come the car. I immediately checked my gauges and saw everything looked normal and then i smelled coolant, saw steam coming from the hood and pulled over. I popped the hood and found that the left-hand side of radiator hose had blown off where the clamp attaches to the rest of the assembly and fluid everywhere. From there i decided to put a regular hose clamp on just to get me home, as well as put more coolant in. I let the car cool down and checked (while it was idling) for leaks before trying to get back home, which was no more than a mile and half away. This did get me home, however, as soon as i got into my driveway the coolant light came on. So at this point my questions is what could have made the original clamp blow off and did the computer just take some time to recognize there had been a loss of coolant. If you could give me some advice on what to look into next before i take it into a repair shop and have them tell me that i need a new radiator/thermostat/hoses/clamps and what not, i would greatly appreciate it.

[aampsmb]

It's hard to say what made the radiator hose come loose. Go online and order a new radiator hose and install it yourself. The hose is very easy to replace. After you replace the hose open the bleeder screw on the radiator hose and refill until coolant spills from the bleeder. Do this with engine cold. Start the engine and run until up to operating temperature. Then check for leaks. The coolant light should go out. Good luck!

[AlpineSixAndSeven]

also get a new radiator cap cause it can be over pressurizing the system...

[aampsmb]

Good point.

[Bishopfolds]

Yeah, i'm gonna go ahead and replace both the hose and cap. I went out today and started the car up in the driveway just to take a closer look at what all was going on. While i let it warm up i checked the fan and noticed it wasn't turning. Since beoming a new BMW owner, i've never noticed if the fan cuts on only when needed or if it should be running as soon as the engine is turned over. Also, is the Chilton's Manuel worth getting for BMWs or is there a better alternative?

[Steve323i99]

Bentley manual seems to be the top choice for service manuals on BMWs. They run around $70-100 depending on where you can find one vs. the $20 of a chiltons or heyes.

[TRuckee]

I'd concur that the Bentley manual is a good choice. Also be advised that it's hard to get ALL the air out of these systems. Keep bleeding...! I had a similar vehicle and had problems with the coolant system. The plastic parts just aren't long-lasting. Keep an eye on the expansion tank and the other elements of the up-front cooling. It's all pretty easy to DIY service, but you may need some ( cheap ) special tools. TR

[Alandi]

Yesterday while driving normally I noticed steam coming from under car and hood. Car recently had a leak in the valley pan gasket which was repaired at Indy. Temperture gauge was reading normal and no 'low coolant' indicator. Turned back home less than 1 mile. Pulling into drive way 'low coolant' indicator came on. Popped the hood to find the upper radiator hose had popped off and coolant everywhere. Thought maybe the clamp had just worn out or something so I replaced it with a regular screw clamp, filled it back up with coolant.
Ran to the store today and the temperature gauge went all the way to red. Popped the hood. Hose popped off again, not as much coolant. Thought I just caught it early and maybe I didn't tighten the clamp enough. Put back on the clamp and tightened it good. Temperature gauge was at red still, home was a short distance so drove it home. On the way the temperature gauge swung back to normal. Then the low coolant indicator came on. Temperature gauge started climbing slowly, but didn't get too hot. Pulled into the drive way and heard a loud pop. Popped hood and hose popped off again and a whole lot more coolant everywhere.and coming from under the car too.
Wondering if/ why pressure is building up in the cooling system that's causing the hose to pop off. Read a few post on here and (this might be very obvious) could it be that there is air in the system and it needs to bleed or could there be a bigger problem?

[witeshark]

Air in the system is very likely.

[bmwowner99]

After replacing the radiator, hoses, thermostat and the cap, I found out the only thing that would stop my radiator from blowing the hose off the radiator and running hot is to bleed the air out of it! WOW~