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Harry
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21 Posts
Discussion Starter #1 (Edited)
Greetings all.

It's a 2008 650i coupe.

Symptoms, This happened very quickly. All within 1 mile. Has anyone had the same symptoms? If yes, what was the fix? I'm trying to avoid firing the parts cannon at the car.

1) Step on gas, no power
2) A/C started to blow warm air, turned on MAX air and it turned itself off.
3) Low coolant light came on
4) On screen, "Engine hot" drive slow
5) On screen, "Engine hot" STOP
6) pulled over and the upper radiator hose blew off.

I used a temporary clamp and attached the upper hose. Filled it with fluid and let it run for an hour and the car was fine. Installed a new hose and new thermostat. Drove the car 4 miles and the same problem, except I stopped before the hose blew.

That morning I had the windshield replace due to a rock hit. I also had some of the leather on the dash glued down before putting in the new windshield. This should have nothing to do with overheating but I thought I'd mention it.

Thoughts on this problem?
Thanks
Harry
 

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Michael
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2,211 Posts
did you notice if the fans were operating???, did you have to fill with a lot of coolant, are any of the pipes compressed air lock etc. Any obvious signs of leaks
 

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Harry
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21 Posts
Discussion Starter #3
did you notice if the fans were operating???, did you have to fill with a lot of coolant, are any of the pipes compressed air lock etc. Any obvious signs of leaks
Michael,

When the hose blew off, lots of fluid and steam covered the engine bay, so most of the coolant was gone. No sign of any leaks prior to the overheating. I check the overflow tank weekly. I'll check the fans and the other hoses tomorrow as I had the car towed to a garage for repair.

Cheers
 

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Registered
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2,484 Posts
I don't know if this will help, but years ago I had a 1976 320i that did the same thing. Turned out to be a bad radiator.

I doubt the repair you had done could have caused this issue.
 

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Super Moderator
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8,131 Posts
This sounds like the cooling fan is toast, never a warning until the engine runs hot. It will run on certain speeds, but when the engine runs hot, the fan will not run. There are 4 speeds on the cooling fan, controlled by the sensor in the lower radiator hose.
 

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163 Posts
This sounds like the cooling fan is toast, never a warning until the engine runs hot. It will run on certain speeds, but when the engine runs hot, the fan will not run.

Had this exact issue with a mid 90s XJ6 and it was down to rubbish OEM temp sensors for the fan. I ended up scrapping the entire assembly and used a DB7 V12 double fan (they were cheap back then and the perfect fit lol), and wired them to a pre-set thermistor so they came on at the desired temp (and I could adjust it using nothing more than a screwdriver).

Don***8217;t look past the easy things. It***8217;s usually nowhere near as bad as it looks.

Good luck and post your findings when you get them


Sent from my iPhone using Tapatalk
 

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Registered
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94 Posts
This sounds like the cooling fan is toast, never a warning until the engine runs hot. It will run on certain speeds, but when the engine runs hot, the fan will not run. There are 4 speeds on the cooling fan, controlled by the sensor in the lower radiator hose.
had a similar issue. Mine was fine at cruising speed but at lower speeds would overheat. Replaced the fan and sensor and all is good again.
 

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507 Posts
had a similar issue. Mine was fine at cruising speed but at lower speeds would overheat. Replaced the fan and sensor and all is good again.
I had that in my E28 when you actually had a water temp gauge in dash. A stuck shut thermostat will blow off the upper radiator hose.
 

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Super Moderator
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8,131 Posts
had a similar issue. Mine was fine at cruising speed but at lower speeds would overheat. Replaced the fan and sensor and all is good again.
The air going thru the grille will keep the engine cool traveling down the road. When you stop in traffic, it will overheat.
 

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Harry
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21 Posts
Discussion Starter #10
I was off fishing for a few days, needed a break.

Looks like an intermittent failure of the fan. It would turn on and off any time it wanted. Put a new fan in today and so far it's fine.

Thanks All!
 
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