E46 OBC Running Temps ?

[Charlie Brown]

Hi all

I was wondering how if any other E46 330i driver has ever watched their temp closely via the OBC (option 19 subset 7) to see what their average temps are ?

Since my previous thread re the water heater valve I have learnt this and now look at it regularly. I think I might have an issue with it though as my car seems to run between 99 and 106 on average and is constantly fluctuating.

Can anyone else post on what their trends on their I6 is / are vs mine and perhaps suggest what is causing it to run so hot ?

I have no errors / complete new cooling system all OEM 3 years back / 50 000kms back.

The gauge is always straight up at the "12.00 o'clock position" ?

 

[Waseem 333i]

I have done this test before on my diesel 6 cylinder.Air temp was 25 degrees. From cold start till guage got to centre the coolant temp was 77 degrees. Took 5km of driving to get there. Then another 4km of driving to get to 91. At normal highway speeds driving behind another car with air temps of 32 degrees the coolant fluctuates between 95 an 98. with no car in front its at 91 or 92. Ive never checked the temps when driving hard. When i tested it was normal driving

 

[kilotango]

i had an issue where the bleed screw cracked, and i NEARLY overheated the 330ci.. since then i've been paranoid and i've got a scan gauge hooked up which reads live temps off the obd2 port. mine fluctuates between 87 and 97 degrees, i've never seen it go higher that 98 even on the hottest days with A/C running. from the research i've done 97-98 Degrees is the correct magic number on these cars.

you could try flushing your coolant and filling with some nice new stuff. just make sure its bled properly afterwards. if you have a manual gearbox, check that the electric fan is working. if its auto like mine, you'll have a fan clutch which engages at certain temps and makes a loud fan noise when you accelerate..check if these are all working correctly as this would cause higher running temperatures. If you had the thermo changed historically, can you remember if it was OEM or aftermarket one? your thermo could be kicking in later if its aftermarket/old/not working correctly.

if you're keen on reading live stats.. checkout my original thread here.. i cant recommend the ultragauge enough. that BMW coolant temp gauge CANNOT be trusted under any circumstances.



http://www.bmwfanatics.co.za/showthread.php?tid=70050

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i've just seen your posts about changing the water heater valve recently... was this done already? if yes, then they might not have bled the system properly.

 

[Blue Shirt]

Temps up to 106°C are too high. If you are sure that the thermostat, waterpump and radiator are all good, perhaps your viscous fan (if auto gearbox) or electric fan (if manual box) is not working properly. Replace the viscous coupling or the temp switch for the electric fan depending on which one you have.

My E46 325i (with autobox) has the same problem, temps shot up to over 100°C when coming to a stop in traffic. I replaced the viscous fan and the thermostat, since then I never see temps over 97°C.

Many people neglect the radiator, a good flush or chemical cleaning will remove a lot of sludge/sediment which can restore the full cooling capacity.

The temp gauge on E46 will read "normal" i.e. needle in the middle with actual coolant temps anywhere between 80 - 120°C.

 

[Charlie Brown]

Thanks all for the replies

I agree that 97' 'ish should be the magic number here as that's what's stamped on the OEM T/stat. I replaced all my parts with OEM parts, bar the radiator that came from Silverton.

I would have guessed that I had a airlock, so i re-bled the system this weekend and still saw these temps this morning on the way into work. Both on the freeway and smaller roads.

Fan appears to to be working okay, I still has it's two stages slow when aircon is on and then faster when it get's hotter - but how do I know if it's really blowing hard enough ?

The fact that I see these temps on the freeway is concerning as I would assume the fan is not required when on the freeway ?

This would then point to a T/stat, pump partial failure or flow related issues ?

 

[kilotango]

i reckon start with a re-bleed again... that almost always causes kak with temperature probs like this:

the correct way to do it if i remember:

- leave engine off
- open bleed screw and radiator cap off exp tank
- turn key on and put heater to max heat and slow speed
- keep filling coolant into exp tank until overflow from bleed screw
- keep filling until bubbles stop from bleed screw
- close cap and bleed screw, drive around
- wait to cool then check level in exp tank.

after that keep checking the level every day until you find you dont need to add any more fluid.

btw, the level doesnt need to be right to the top full on the expansion tank, it just needs to be filled enough so the float maxes out. you need to leave that gap of air free in the expansion tank. and your coolant mixtures need to be 50/50.

 

[Charlie Brown]

Just a quick update here on this matter;

On Saturday I found the original T/Stat that I replaced 3 odd years ago and installed that one into my car. I filled, bled and test drove - voila got to 97 / 98 and no further, and it moved between 83 & 98 between driving on the freeway, with or without the aircon on etc etc.

I then went to agents and got a brand new T/Stat, new coolant and distilled water. Spent Saturday afternoon and Sunday flushing the cooling system, replacing the T/Stat bleeding, cleaning and testing.

The trip to work this morning it ran between 88 > 97 all the time, needless to say I'm really chuffed having fond the problem.

Why a relatively new T/stat failed so early really pisses me off.

 

[Blue Shirt]

Thanks for the update, glad that you found the culprit.

 

[kilotango]

Thanks for the update, glad that you found the culprit.

:withStu: for sure, OP well done on sorting this out before anything major happened. go have a few beers now and rest easy

 

[Charlie Brown]

Thanks to all for your advice and input here.

Just a further update now that the new thermostat has been in for a couple days, is that if you drive normally my car stays perfectly between 96 & 98 degrees.

When you cane it a little the temps actually drop into the 80's.

I strongly advise all owners to keep an eye on this and learn to use the OBC etc as its very valuable information as the gauge is so useless. This can help diagnose early T/Stat failure etc etc.

@ kilotango - as an 46 owner you never rest easy, there's always something that needs your attention !

 

[kilotango]

@ kilotango - as an 46 owner you never rest easy, there's always something that needs your attention !

hahahahahaha too true...unfortunately

if we lived in Europe or the States where parts were easily and cheaply available.. it wouldnt be so bad. i dont mind fixing some of the common issues these cars have, its getting the damned parts that annoys me.

correct... mine drops to around 83C or so when i thrash it... so your car is on point right now.

most people just dont care much for engine temp monitoring until they experience an overheat, or a near overheat sadly. i didnt realise how easily these aluminium engines could be damaged until after i had an incident and researched it.

that BMW temperature gauge is a serious hazard.... it just cant be trusted:RedNo: