BMW E39 - overheating

jimjom

Hi All,

I have a pre-facelift BMW E39.
After about 5 minutes from cold it reaches just under 3/4 on the temperature gauge and stays there. It does not fluctuate.

I know this is a common problem but it can have different causes.
The clutch fan works fine.
I am hoping that it just requires a new thermostat.

The car recently had the following replaced:

• a new waterpump
• waterpump pulley
• coolant pipe

Surely I'm on the right track with a new thermostat?

tks

MercMad

I would say you could do with changing the stat, but have the symptoms changed at all after the work you've done ?

They are a notoriously difficult car to bleed sometimes, let the car warm up and open the plastic bleed screw on the pipe between rad and block. Make sure your interior heater is set to hot. You may have to do it a few times. Be careful of hot water and moving parts.

jimjom

MercMad wrote: »

I would say you could do with changing the stat, but have the symptoms changed at all after the work you've done ?

They are a notoriously difficult car to bleed sometimes, let the car warm up and open the plastic bleed screw on the pipe between rad and block. Make sure your interior heater is set to hot. You may have to do it a few times. Be careful of hot water and moving parts.

Thanks for the reply.
It previously overheated but the engine was shut off in time.

So at just under 3/4 is where the engine temperature sits.
The strange thing is that it doesn't move from that once warm.
I had to take it on an hour motorway trip last week and it didn't move from that position.

gavman1

If it was my car i would firstly check if the guage is reading true.if your local indy has a heat sensing gun you could verify this very quickly.after that i would def get a new t-stat if only cos its the only thing that hasnt been changed.ye probably already know this but i'll say it anyway, these engines are a one shot deal with overheating,they pull the head bolt threads and even the timesert repair is never really successful, well at least not in the ones ive seen.is it the single vanos?

jimjom

gavman1 wrote: »

If it was my car i would firstly check if the guage is reading true.if your local indy has a heat sensing gun you could verify this very quickly.after that i would def get a new t-stat if only cos its the only thing that hasnt been changed.ye probably already know this but i'll say it anyway, these engines are a one shot deal with overheating,they pull the head bolt threads and even the timesert repair is never really successful, well at least not in the ones ive seen.is it the single vanos?

Thanks. I'm aware of the consequences so hopefully a new thermostat is all!

Good idea with heat gun, didn't think of that.

Leonard Hofstadter

Have you checked the temperature using the hidden menus?

The temperature gauge in these cars is heavily buffered so the second white mark means its actually running at 120 degrees, so that's hot! Dead centre is anywhere between 75 and 115 degrees. Start of the red is 124 degrees.

The six pot petrols should run at 97, the V8s are meant to run at 109 (unless it's an M5, which is mean to run at 82) and the diesels should be on about 90. Under high loads the map controlled thermostat should bring the petrols down to 82 degrees or so.

I would be rather concerned that the gauge is pointing that far over consistently, unless there's something wrong with gauge itself. It does seem very strange, normally once they go past the middle they go into the red very quickly.

jimjom

captainspeed wrote: »

Have you checked the temperature using the hidden menus?

The temperature gauge in these cars is heavily buffered so the second white mark means its actually running at 120 degrees, so that's hot! Dead centre is anywhere between 75 and 115 degrees. Start of the red is 124 degrees.

The six pot petrols should run at 97, the V8s are meant to run at 109 (unless it's an M5, which is mean to run at 82) and the diesels should be on about 90. Under high loads the map controlled thermostat should bring the petrols down to 82 degrees or so.

I would be rather concerned that the gauge is pointing that far over consistently, unless there's something wrong with gauge itself. It does seem very strange, normally once they go past the middle they go into the red very quickly.

No I havent checked the hidden menus.
It gets to just under the 3/4 mark after about 5mins (I timed it today).
Its certainly running hot but it does not budge from that mark on gauge.
The old trick of turning on the hot air does nothing to reduce it.
Thats where it stays!