Temp gauge moving upwars

[ErdeM3]

Hello folks,

i have finally did a “long” trip yesterday with my 3 year old where i put the most miles on the M after the kids. 600 miles in one day where it was 105 outside…Maybe not the best choice for a black on black convertible…i had an aux fan for back seat

So, i have a 2006 m3 at 113 miles, since last 6 years, i barely driven the car 3000 miles in total… I would get check engine light randomly, engine not reaching target temp and temp gauge will be a little below the middle..when it is really cold in Winter i would see some coolant leak. So after every bard winter, i would top off the cooling system

Before this trip i decided to change the thermostat and temp sensor and replace all the o-rings and gaskets in the cooling system and flush the radiator, drain the coolant without removing the engine drain plug ( since i could not reach it and gave up).

i pressure tested the system, test drive for a week or so, roughly 200 miles. All looked good. Temp gauge dead right in the middle, check engine light cleared it self… i am very happy, right… up to this point i have never seen temp gauge moving upwards on this car, since 8 years!

so we start the trip yesterday, within first 15 min, i see the temp s moving a little upwards beyond the middle( almost reaching 3/4) and coming down again. Over the course of the drive it, i have observed this coupe of times…

i thought well it is so freaking hot and i need clean air…we managed it make it to our destination without any problem.

it did it again today when it was “only” 92 outside during a short drive… i was about to arrive home and parked in front of my yard and watched the temp gauge to see if it will continue rising… nope come back down in the middle once again…

i am so sorry for the long backstory to this…


Where did I fail?
or am i in trouble?
Is this something normal?
Is my water pump failing, or should i think replacing of the balast and upgrade it to Electic fan?

FYi, i have not seen engine oul temp rising above 210…

Thank you all, have a great night

[sapote]

Before this trip i decided to change the thermostat and temp sensor and replace all the o-rings and gaskets in the cooling system and flush the radiator, drain the coolant without removing the engine drain plug ( since i could not reach it and gave up).

What temp sensor -- engine sensor on the pipe next to the head, or the radiator lower hose sensor? The lower hose sensor control when the elec fan running. Do you know if the elec fan front of radiator ever running?

[FBloggs]

From your description, it Sounds like there was a lot of air in the circuit, and it was initially stuck between the radiator and the Tstat, then it was purged.
There could be some more air in the circuit, so the circuit may need to be bled once more.
If the problem persists after another bleed, the mech fan if applicable may need to be checked for function as well as the electric fan infront of the radiator( try spinning it by hand...should move freely).

[Arith2]

Use this to bleed and fill coolant. It's an absolute requirement on newer cars and highly suggested in every situation. Almost doesn't matter how much coolant you drain, though BMW coolant have a lifespan of 4 years so flushing is a very good idea. This will suck all the air out.

https://www.ecstuning.com/b-schwaben-parts/coolant-refill-air-purge-tool/003466sch01/

[ErdeM3]

Thank you all, i will try bleeding again and go from there…

and it is the temp sensor on the lower radiator hose…

and fan moves freely without any problem… i ll keep an eye.

appreciate the answers everyone…

[ErdeM3]

So, i actually just open the bleed screw before stating the car and i heard the air coming out and drove the car all day… no issues.

i feel like an idiot, cause i always thought this was a self bleeping system for whatever reason..

Anyhow so far so good, as always appreciate the wonderful help from all of you!

cheers

[jet_dogg]

PagingTbonem3

[sapote]

So, i actually just open the bleed screw before stating the car and i heard the air coming out and drove the car all day… no issues.

i feel like an idiot, cause i always thought this was a self bleeping system for whatever reason..

Anyhow so far so good, as always appreciate the wonderful help from all of you!

cheers

The M3 coolant should be a self-bleeding system, as the tank sits higher than the upper hose with the bleeder. There is a small hose going from the bleeder hose to the tank, and so the air inside the upper hose should be flowing up to the tank and there should be no air in the upper (as you said opened the bleeder and air was coming out). So maybe that small hose is clogged up.

[eacmen]

“burping” the system by squeezing the large hoses and then opening the bleed screw is all i’ve ever needed to do.

[Arith2]

“burping” the system by squeezing the large hoses and then opening the bleed screw is all i’ve ever needed to do.

For the most part, this is all that's necessary. There is nothing special about our coolant system except its insufficiency to deal 100+ degree heat.

[jet_dogg]

I was going to say our cooling system is rather robust and one of the better systems bmw has engineered over the years.

I frequently saw issues with all other E chassis cars over the years before most people here owned m3s.

[Jimbo's M]

There is nothing special about our coolant system except its insufficiency to deal 100+ degree heat.

Says you. This will be my M's twentieth summer here in Tucson, and we get a hellofalot hotter than you do. We average 60+ days over 100F every summer (115F+ is not uncommon), and the indicator is never more than a needle's width past half way.

[TexaZ3]

How is your clutch fan? Also, at this point, radiator might be just clogged and old, I'd replace if this continues.

[ErdeM3]

How is your clutch fan? Also, at this point, radiator might be just clogged and old, I'd replace if this continues.

It is still the original but i will upgrade the whole system in due time…

it seems there was air stuck in the circuit and bleeding solved my issue…

[TexaZ3]

It is still the original but i will upgrade the whole system in due time…

it seems there was air stuck in the circuit and bleeding solved my issue…

I'm not 100% convinced, the system on E46 is self-bleeding, so I somehow doubt that air was causing the temp spike.