Thermostat E46 problem?

thepharcyde

thepharcyde

thepharcyde

Soldato
Joined
17 Mar 2004
Posts
8,259
I have noticed recently with the cold weather that the thermostat gets upto the midway point with the heater on 25'c, but as soon as I get out of town onto NSL roads doing 60/70mph it drops under the midway point max being the indicated red line below.

temp.jpg


Anyone else who has a 330/530 experiencing this/and is it normal? Is the thermostat on its way out. I have noticed that my ave mpg on the computer has dropped from 26.4 to 25.9 but that was with some serious canning over the weekend!

Many thanks
 
Both of my 330's did this....who cares as long as it stays within operating temperature at all times. Its not a large fluctuation.
 
not a 330, but the 320d does a similar thing, I just put it down to shoddy european cooling systems that must not have changed that much.
 
I will mention it to the dealers, and see what they say. Would it log a fault on the ECU if it was faulty, because going by past experiences non logged ecu faults are normally passed off as 'cannot replicate fault' when I pick it up.

Thank you for the advise
 
As i say, both my 330's did it. Both were mint examples with no faults and had FBMWSH with very low emission results on their mot's. Dont worry about it.
 
Dead common problem, every 3 + 5 Series I owned did this, to fix it replace the thermostat no more than £50 in parts and took me 1/2 hour to replace.
 
Jez said:
As i say, both my 330's did it. Both were mint examples with no faults and had FBMWSH with very low emission results on their mot's. Dont worry about it.
Click to expand...

This is very poor advice. If both your 330's did it, then they were both broken. The temperature guage on an M54 engined car should take about 4-6 minutes to rise from cold to the centre of the guage depending on ambient conditions. The diesels are similar but can take twice the time to warm up.

Once there, it should absolutely never move from centre. The system is built to ignore minor normal temperature fluctuations (ie, heavy traffic, hot day) and not show temperature gain or loss on the guage until the temperature is outside normal operating conditions.

If it moves from centre when the car is operational, there is a cooling system fault somewhere - simple as that. It sounds like the thermostat in this case. It will probably not log as a fault on the ECU.
 
Dick Lovett dont agree, they were centre 90% of the time, unless blasting around at speed, where they would fall as indicated.

Perhaps it is a slight fault, but its hardly something worth getting looked at. I thought the same which is why i visited them at the time to ask, they said not to bother.
 
Jez said:
Dick Lovett dont agree, they were centre 90% of the time, unless blasting around at speed, where they would fall as indicated.

Perhaps it is a slight fault, but its hardly something worth getting looked at. I thought the same which is why i visited them at the time to ask, they said not to bother.
Click to expand...

You were given poor advice. The cooling system is the weakness of the M54 engine. Any problems should be attended to ASAP. pharcydes car is under warranty, to not have this problem fixed is ridiculous.

Why would you be happy to drive around in a car with a non functioning thermostat?
 
Was only going on the fact that both of mine did it, and the fact that a main dealer had told me it wasnt an issue :) If its under warranty then obviously he might as well get it fixed if it really is a fault.
 
Jez said:
Being told by a few people on IRC that as your car has a warranty then you might as well insist that it gets looked at. For a free fix you might as well.
Click to expand...

Even if it wasnt under warranty it should still be fixed. It's not expensive and it's best to catch problems with the cooling system before they develop into something altogether more annoying and expensive.
 
Seems strange that they wouldnt have tried to get me to book it in for a fix. Youd have thought they would have been glad to fleece me for some main dealer labour charges. Maybe they were just really busy and couldnt be arsed :)
 
lazy stat, lazy stat leads onto failed stat, failed stat leads onto failed head.

may be fine until the end of time but for a simple fix just get it sorted.
 
Jez said:
Seems strange that they wouldnt have tried to get me to book it in for a fix. Youd have thought they would have been glad to fleece me for some main dealer labour charges. Maybe they were just really busy and couldnt be arsed :)
Click to expand...
They wanted to fleece you for a blown head gasket instead :p
 
another issue for bmw owners to keep an eye on this time of year is the water pumps, the blade section cracks slightly so it slips on the spindle, itl spin fast enough at times to keep things cool but you may notice at certain revs or circumstance the temp starts shooting up.

done a few this month now, mostly late 90's models.
 
my e36 325i use to do this until i changed the stat and now it sticks bang in the middle. I'd say get it in and stat changed. BMW's are known for poor cooling systems.
 
You must log in or register to reply here.
Back
Top Bottom