Faulty thermostat?
 

Hello again,

I have a 2000 528i. Once in a while I will glance down and see the
temperature guage in the red. My first reaction was the car was
overheating, but then suddenly the needle went back down in the normal
area. Most of the time when this happens I had just started the car. It
happened yesterday while I was stuck in traffic. I know the engine was not
overheating becuase the needle will go down very fast.

Is this a thermostat going bad?

Please advise,
Jeff

In article >,
Jeff > wrote:
> I have a 2000 528i. Once in a while I will glance down and see the
> temperature guage in the red. My first reaction was the car was
> overheating, but then suddenly the needle went back down in the normal
> area. Most of the time when this happens I had just started the car. It
> happened yesterday while I was stuck in traffic. I know the engine was
> not overheating becuase the needle will go down very fast.

This is because the gauge doesn't read temperature directly. It is
controlled by the engine ECU, and reads exactly in the middle over a wide
range of (safe) temperature. As soon as that limit is exceeded it will
climb quickly, and fall quickly too when the temperature drops.

--
*When cheese gets its picture taken, what does it say? *

Dave Plowman London SW
To e-mail, change noise into sound.

I would also check the auxiliary fan for proper working order.

.......Chip

"Dave Plowman (News)" > wrote in message
...
> In article >,
> Jeff > wrote:
> > I have a 2000 528i. Once in a while I will glance down and see the
> > temperature guage in the red. My first reaction was the car was
> > overheating, but then suddenly the needle went back down in the normal
> > area. Most of the time when this happens I had just started the car. It
> > happened yesterday while I was stuck in traffic. I know the engine was
> > not overheating becuase the needle will go down very fast.
>
> This is because the gauge doesn't read temperature directly. It is
> controlled by the engine ECU, and reads exactly in the middle over a wide
> range of (safe) temperature. As soon as that limit is exceeded it will
> climb quickly, and fall quickly too when the temperature drops.
>
> --
> *When cheese gets its picture taken, what does it say? *
>
> Dave Plowman London SW
> To e-mail, change noise into sound.

Faulty thermostat?
 

On Wednesday, October 6, 2004 at 5:23:50 PM UTC-5, Jeff wrote:
> Hello again,
>
> I have a 2000 528i. Once in a while I will glance down and see the
> temperature guage in the red. My first reaction was the car was
> overheating, but then suddenly the needle went back down in the normal
> area. Most of the time when this happens I had just started the car. It
> happened yesterday while I was stuck in traffic. I know the engine was not
> overheating becuase the needle will go down very fast.
>
> Is this a thermostat going bad?
>
> Please advise,
> Jeff

Mine overheated the first time used the AC. Wasn't even that hot out. Turning the hater on full didn't help much.

Faulty thermostat?
 

In article >,
> wrote:
>On Wednesday, October 6, 2004 at 5:23:50 PM UTC-5, Jeff wrote:
>> Hello again,
>>
>> I have a 2000 528i. Once in a while I will glance down and see the
>> temperature guage in the red. My first reaction was the car was
>> overheating, but then suddenly the needle went back down in the normal
>> area. Most of the time when this happens I had just started the car. It
>> happened yesterday while I was stuck in traffic. I know the engine was not
>> overheating becuase the needle will go down very fast.
>>
>> Is this a thermostat going bad?

Well, it's been 13 years since this guy posted and I don't know what he
found was wrong. But given those symptoms, I'd suspect a bad instrument
panel ground before I'd suspect an overheating issue. Still, those cars
are very prone to cooling system problems.

>Mine overheated the first time used the AC. Wasn't even that hot out. Turning the hater on full didn't help much.

Your 2000 528i overheated the first time you used the AC? Was this 17 years
ago, or have you been driving it that long without the AC? How many times
have you replaced the water pump in that period anyway?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."