Just overheated, help!

J

JimBob78

Member
Hi
I was just driving over peaks and noticed my gears started auto changing even though in manual, I then noticed after a mile or so that the temp gauge had started to climb, it continued until the red light came on and I pulled over. Managed to limp to a garage and got recovered. Anyone any ideas what this might be caused by? The fan seems to work, never heard it come on before but was working overtime with no benefit....
Cheers
 
Could be a number of reasons but if N52 engine don't the electric water pumps need attention in some cars 60 - 70k miles?

I think symptoms are change in cooling fan frequency and higher temp
 
My thoughts were water pump or thermostat, it's done 78k so that makes sense. Don't suppose either are quick and easy jobs!?
 
Have you got the si model? Anything over 70k & the water pumps are on thin ice, bit pricey as well I'm afraid-got to be £500+ from a bmw dealer to replace :(
Rob
 
Yeah it's an si, usually avoid BMW tbh. Apparently it's a pretty easy diy...
I might try bleeding the system first, I guess if nothing happens then I know it's the pump. Anyone done the a bleed on these?
Cheers
 
They can auto bleed if you turn on the ignition & hold the throttle down for ten seconds or so, it's something like that & takes about ten mins from memory, I got an oem pump for £280 and as you say, it's an easy diy-about 4 bolts (which should be replaced) and a couple of jubilee clips and you're done :thumbsup:
Rob
 
I wonder if anyone knows how these pumps fail.If it is the electric motor that stops it should be possible to "listen" to see if its running?
If internal seal fails and floods the motor?,or impeller comes off?It may be possible to dissect and reseal?Someone on here hopefully knows.On such a great engine,a bit naughty of B.M.W.to have such a short life expectancy of the vital pump.Good luck Sir
 
jack07 said:
I wonder if anyone knows how these pumps fail.If it is the electric motor that stops it should be possible to "listen" to see if its running?
If internal seal fails and floods the motor?,or impeller comes off?It may be possible to dissect and reseal?Someone on here hopefully knows.On such a great engine,a bit naughty of B.M.W.to have such a short life expectancy of the vital pump.Good luck Sir
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I've only read of electronic failures, not mechanical ones-when mine went it was still working but not properly, I think the diagnostics said "implausible pump speed" on cold start up my cooling fan was revving high/low which seems to be a sign of impending disaster.
I didn't want to flambé my engine so replaced the pump before it led to over heating, apart from the high cost I don't think ten years is a bad life for the pump, I shouldn't have to change it again :wink:
Rob
 
Interesting stuff,Did you bin the old one?If not it may be good to get an ohm meter reading to compare with a healthy one?Did it sound any different at all?Still think they should last much longer,compared with say alternators or modern mechanical pumps.Just parted with my old Ford focus on original water pump and alternator still running sweetly at 160K.Thanks for sharing info.
 
jack07 said:
Interesting stuff,Did you bin the old one?If not it may be good to get an ohm meter reading to compare with a healthy one?Did it sound any different at all?Still think they should last much longer,compared with say alternators or modern mechanical pumps.Just parted with my old Ford focus on original water pump and alternator still running sweetly at 160K.Thanks for sharing info.
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I've still got the old pump stored in my garage (God knows why) I could dig it out & take some resistance readings if you like?
Ps, it still sounded normal (pretty much inaudible)
Rob
 
JimBob78 said:
My thoughts were water pump or thermostat, it's done 78k so that makes sense. Don't suppose either are quick and easy jobs!?
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Symptoms sound like the water pump or thermoststat - mine did the exact same thing last summer. I ordered a Pierburg Waterpump from Eurocarparts approx £350 ish - this is the same maunufacturer who make the OEM part for BMW. Ordered a thermostat from BMW also approx £90 - its is highly recommencded to change the thermostat at the same time, and only buy the BMW coolant(dont buy cheap coolant off high street). Lastly dont forget the three new aluminium bolts which connect it all to the engine block.

I installed mine myself, not a hard job if your ok on the tools (look on youtube for an install video) :thumbsup:
 
Rob,Smartbear,Yes,would be good to publish readings to compare with a pump in good health to help DIYers confirm pump on way out? :)
 
Sorry to hear of your problem OP. :(

Symptoms sound just like those of my Ruby Black Coupe with N52 engine when the water pump died late last year at about 9 years old and 61,000 miles.

New OEM pump was £500 and thermostat was another £100, plus fitting (not keen on even a simple job in the outdoors that time of year)!

Hope you get yours sorted quickly and at lowest possible cost - but it is worth the expense to have an N52 in full health! :thumbsup:
 
Thanks for all the advice guys, I've noticed heater is not hot so pretty sure it's water pump but I'm going to try bleeding the system today in the hope it's just an air lock, fingers crossed...
 
jack07 said:
Rob,Smartbear,Yes,would be good to publish readings to compare with a pump in good health to help DIYers confirm pump on way out? :)
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OK, just found pump & it has 4 pins on the connector which gives a few permutations, I've measured from pin 1 to each pin in turn & read just under 0.5 m ohms (don't forget my pump was still working but on its way out)
IMAG3248.jpg
IMAG3247.jpg
Regards
 
Update....
Running the auto bleed did nothing but make my battery flat... my fault I guess!
It's been properly diagnosed and the pump has failed, total cost to replace 330 all in at Pryor Automotive in Sheffield. That's using a pierburg pump which is OEM.
This happened on the first day of my week off, quite irritating!
Cheers for the help gents
 
JimBob78 said:
Update....
Running the auto bleed did nothing but make my battery flat... my fault I guess!
It's been properly diagnosed and the pump has failed, total cost to replace 330 all in at Pryor Automotive in Sheffield. That's using a pierburg pump which is OEM.
This happened on the first day of my week off, quite irritating!
Cheers for the help gents
Click to expand...
That's cheap,you could doi with changing the thermostat as once they have over heated they become unreliable .
 
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