replaced thermostat - still cold

I replaced the thermostat on my 1990 520i m20, (and flushed & changed the
coolant while I was at it) because the temp. guage was remaining in the blue
zone. Now it hits the 1/4 mark & stays there, unless I'm sitting in traffic
in which case it may go up between 1/4 & 1/2. It also still takes a long
time to warm up. Decentish, but not exactly red-hot, heat from the
ventilation (& only cold air from the centre grilles!).

I've tested the rad fan coupling, and found that though it spins all the
time, it can be stopped with rolled-up newspaper when the engine is running
at it's normal temp.

Could the thermostat be faulty (bought from Eurocarparts), or could the
guage be reading cold? If the 'stat is faulty, I'd happily change it as it's
so cheap, but a bit time-consuming to drain, & fill / bleed the system - any
way of changing it without a complete drain?

TIA,
Jamie

Jamie Fisher wrote:
>
> I replaced the thermostat on my 1990 520i m20, (and flushed & changed the
> coolant while I was at it) because the temp. guage was remaining in the blue
> zone. Now it hits the 1/4 mark & stays there, unless I'm sitting in traffic
> in which case it may go up between 1/4 & 1/2. It also still takes a long
> time to warm up. Decentish, but not exactly red-hot, heat from the
> ventilation (& only cold air from the centre grilles!).
>
> I've tested the rad fan coupling, and found that though it spins all the
> time, it can be stopped with rolled-up newspaper when the engine is running
> at it's normal temp.
>
> Could the thermostat be faulty (bought from Eurocarparts), or could the
> guage be reading cold? If the 'stat is faulty, I'd happily change it as it's
> so cheap, but a bit time-consuming to drain, & fill / bleed the system - any
> way of changing it without a complete drain?
>
> TIA,
> Jamie

Any chance you could have put the thermostat in backwards?

"Randolph" > wrote in message
...
> Any chance you could have put the thermostat in backwards?

Don't think so - it's conical, and I'm pretty sure it went in the same way
as the old one.. unless the old one was in backwards too...

i had some problems with my thermostat fitting a short while back on my 1990
530. i ended up changing a sensor that screws into a point close to the
thermostat housing and that seems to have helped. also, be sure to bleed air
from the system using that hex bolt and to top up fluid when car is cold.
btw, my centre vents blow cold all the time - maybe they're supposed to?

mojo


"Jamie Fisher" > wrote in message
...
> "Randolph" > wrote in message
> ...
> > Any chance you could have put the thermostat in backwards?
>
> Don't think so - it's conical, and I'm pretty sure it went in the same way
> as the old one.. unless the old one was in backwards too...
>
>

"Jamie Fisher" > wrote in message
...
> I replaced the thermostat on my 1990 520i m20, (and flushed & changed the
> coolant while I was at it) because the temp. guage was remaining in the
blue
> zone. Now it hits the 1/4 mark & stays there, unless I'm sitting in
traffic
> in which case it may go up between 1/4 & 1/2. It also still takes a long
> time to warm up. Decentish, but not exactly red-hot, heat from the
> ventilation (& only cold air from the centre grilles!).
>
> I've tested the rad fan coupling, and found that though it spins all the
> time, it can be stopped with rolled-up newspaper when the engine is
running
> at it's normal temp.
>
> Could the thermostat be faulty (bought from Eurocarparts), or could the
> guage be reading cold? If the 'stat is faulty, I'd happily change it as
it's
> so cheap, but a bit time-consuming to drain, & fill / bleed the system -
any
> way of changing it without a complete drain?
>
> TIA,
> Jamie


No chance I suppose of the cold air coming through a partly open vent to the
outside?

JB

"mojohotmail" > wrote in message
k...
> i had some problems with my thermostat fitting a short while back on my
1990
> 530. i ended up changing a sensor that screws into a point close to the
> thermostat housing and that seems to have helped. also, be sure to bleed
air
> from the system using that hex bolt and to top up fluid when car is cold.
> btw, my centre vents blow cold all the time - maybe they're supposed to?

I think you're right - I had a later E34 before with adjustable temp through
centre, but this earlier one just don't have that fee-chure.

replacing the sensor in the thermostat housing - that sounds like a good
thing to try then, does anyone know what it's called? I can't find 'coolant
temperature sensor' in eurocarparts.com.

Many thanks,
Jamie