Temperature Issue - BMW E46

kash786 · 10 Oct 2012 at 19:45

Above image is of my temperature gauge on my E46 320D M Sport Coupe, after my 16 mile journey to work.

As you can see, the needle is not really dead center, as you would expect it to be after the journey, has anyone else experienced this?

I suspect it may be the EGR Thermostat that needs replacing? I was actually planning on cleaning out the EGR valve, as it seems to be a common issue with them getting 'clogged' up, would this help?

Brookert · 10 Oct 2012 at 21:28

Does your car ever get to temp, or is it always reading low? For example, my Audi will get to temp around town, albeit slowely. On the motorway, the temp drops far too much. I'm 99% sure it's the thermostat stuck open.

If the temp never gets to what it should, I would say it's a sensor of some sort.

Gaygle · 10 Oct 2012 at 21:30

Thermostat. If you sit in traffic for a while, i bet the needle will start climbing.

Housey · 10 Oct 2012 at 21:35

I believe the thermostats on E46's were a weak point, I had one fail on an old 323 I had some years back, annoyingly just as I was entering the centre of London.

mjt · 10 Oct 2012 at 21:43

Thermostat

/thread

rodenal · 10 Oct 2012 at 22:27

Will be the stat - reasonably easy to change

kash786 · 11 Oct 2012 at 09:52

Housey said:
I believe the thermostats on E46's were a weak point, I had one fail on an old 323 I had some years back, annoyingly just as I was entering the centre of London.

Yep, seems to be the case with these - relatively cheap fix I can do myself.

Spartacus · 11 Oct 2012 at 11:40

Cleaning out the actual EGR will do nothing for the temperature, although its still actually a good idea if youve never done it.

Change the EGR thermostat, Thats the most common cause of low engine running temp on these Cars.

My E90 has recently had new EGR Thermostat and coolant Thermostat due to low running temp.

Cheers

Moorron · 11 Oct 2012 at 13:37

Dont see anything wrong with the picture, My M3 runs like that on the go and climbs to halfway when sitting still.

How long does it take to get there? if its 15 minutes then something is wrong but if its like this after 5 minutes of driving i wouldnt worry.

My GF wrote her old puma off last year and we bought a replacement straight away and the newer one read really low on the guage when the previous one in the middle. I thought the same as you thinking it was running too cold but it was fine.

Anything between the 1/3 and 2/3 line is fine.

Duke · 11 Oct 2012 at 13:47

^ Pretty sure it should always sit in the middle.

thepharcyde · 11 Oct 2012 at 14:44

My 330ci same thing, was thermostat. BMW replaced on drive.

Matt82 · 11 Oct 2012 at 15:16

Moorron said:
Dont see anything wrong with the picture, My M3 runs like that on the go and climbs to halfway when sitting still.

what sort of M3 do you have?

My M3 sort of did that when i got it (it was very broken)

after replacing a lot of the cooling system it now gets to vertical within a couple minutes and never moves from there

kash786 · 11 Oct 2012 at 16:13

I was always under the impression that the needle should always eventually sit in the middle.

My drive to work is predominantly A-roads but along the way I am in slow moving/stationary traffic, so I would have expected the needle to sit in the middle.

Matt82 · 11 Oct 2012 at 16:28

you should expect it to sit in the middle regardless. only under extreme conditions shoudl it go above the middle and it should get the middle from cold in minutes

mjt · 11 Oct 2012 at 20:32

Moorron said:
Dont see anything wrong with the picture, My M3 runs like that on the go and climbs to halfway when sitting still. .

Um, no. My Z3 did that because the thermostat was knackered.
A new one solved the issue!

[TW]Fox · 11 Oct 2012 at 20:34

Moorron said:
Dont see anything wrong with the picture, My M3 runs like that on the go and climbs to halfway when sitting still.

This is because the M3 temperature guage is not damped, whereas the non M power E46's have a damped temperature guage. On the petrol models (The diesel operates similarly but perhaps different control temps) the guage will read centre if the coolant temperature is between 75c and 113c.

kash786 · 14 Oct 2012 at 16:35

So, I spent my Saturday afternoon changing the EGR Stat, also removing & cleaning out the EGR Valve.

Still have the initial issue

..So i guess i'm going to need to replace the main stat, has anyone done this before on these?

rodenal · 14 Oct 2012 at 17:19

If its the same as the e36 the hardest thing you need to do is remove the viscous coupling

kash786 · 18 May 2013 at 12:25

Right, I replaced both stats and the coolant, all was well, car was running absolutely fine.

Now, I've noticed that the car takes a little while longer than usual to warm up, but the temp gauge needle does eventually hit 12 o'clock. I suspect there's air in the cooling system.

Does anyone know how to bleed the system on these E46's?

toyotacelicagt4 · 18 May 2013 at 14:49

Turn heater onto highest heat setting, set to the lowest fan speed, start engine, remove expansion tank cap, slowly open and close the bleed screw on the top hose near the expansion tank until it stops bubbling.