02 540i thermostat? help!!

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dwilli - 20 Mar 2008 02:27 GMT

Couple weeks ago I couldn't get the heater to put out any heat while idling
at startup. Once i got on the highway it was ok. 2 days later i had NO heat
at all and the "check cooling system level" light came on. I added about a
gallon of antifreeze and it seemed ok until today. when I got where I was
going I had to sit and wait...steam started coming from under the hood. I
shut it off and had to leave the car for the day. Got in tonight and
everything was fine until I got stuck in stop n go traffic (NYC) for an
hour. The temp kept rising and the "check cooling system level" light came
on again. It never reached the red zone but I was running the defrost max
button and praying a lot. Once I got to the highway and could move above 40
it was fine.

Does this sound like I just need a new thermostat? 106,000 miles (mostly
highway) and at 100,000 I had the system flushed.

Any ideas are appreciated.

Dale

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RJD - 20 Mar 2008 03:26 GMT

>Couple weeks ago I couldn't get the heater to put out any heat while idling
>at startup. Once i got on the highway it was ok. 2 days later i had NO heat
[quoted text clipped - 14 lines]
>
>Dale

Dale, it sounds like your water pump impeller is slipping on the
shaft. Don't overheat your engine. BMW engines are very sensitive to
overheating. You can do major damage with what appers to be a minor
cooling problem. BMW water pumps are known to have problems.

RJD

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admin - 20 Mar 2008 16:52 GMT

>> Does this sound like I just need a new thermostat? 106,000 miles (mostly
>> highway) and at 100,000 I had the system flushed.
[quoted text clipped - 9 lines]
>
> RJD

Actually - the V8 pump on his car isn't known for this sort of problem.
It sounds as if the car is overheating when stuck in traffic, and that
could be several things..

o - Thermostat is always suspect

o - Leaks are suspect, especially on the V8 cars. Adding a gallon of
coolant is pretty much a clue that there is a SERIOUS leak. FIND where
the gallon of coolant disappeared to. It doesn't just "get low" - if
it's low there is a LEAK.

o - Auxiliary cooling fan can be a problem on that model, and will show
up when stuck in traffic. If it doesn't turn on with the AC - it's dead
and needs to be replaced.

To Dale - overheating a BMW can get very expensive very fast, since the
heads like to warp or crack when this happens. I would quit fooling
around with it and take it to a professional and have it looked at.
Certainly your choice - but if you manage to warp a head, you'll be
looking for a new car rather shortly.

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dwilli - 21 Mar 2008 16:44 GMT

And the winner is..........
...............
.............
.............

admin:
I called my local mechanic who told me it sounded like the cooling
fan...best to take care of it wherever I was. I took it to Park Ave. BMW
near Paramus, NJ since I was staying at the Marriott close by.

Radiator (was leaking)
Thermostat (which I suspected)
Overflow tank
Cooling fan
Fan clutch.

the way they described it, when one goes it trickles to a lot of other parts
in the system. Water pump was OK.
Like I said, it never got to the red and as soon as i could pick up some
speed it cooled back down.
$2,300 later I'm back in business. Can't really complain. It's the first
"big" bill I've had. What pisses me off a little is that I had the cooling
system serviced 5,000 miles ago.

thanks both of you for the advice, though. I love the car and hope I can
hold onto it for another 100,000!

dale

>>> Does this sound like I just need a new thermostat? 106,000 miles (mostly
>>> highway) and at 100,000 I had the system flushed.
[quoted text clipped - 29 lines]
> your choice - but if you manage to warp a head, you'll be looking for a
> new car rather shortly.

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