* E46 Cooling Guide (Information w/parts list/bleeding) *

Originally Posted by bimer21

Yeah sure! And the radiator, when I bought the car the owner gave me the receipt for a new radiator from the dealer 1 month ago! And yes I'm also planning to change both tensioners! I want to leave everything on the coolant system new as well!

Good deal!

I have an interesting observation. My temp gauge (the needle one) has always been behaving normally. It stays at the minimum when cold, and when engine warms up, it gradually reaches the center, and will always sit at dead center.

However, out of curiosity, I checked the digital coolant temperature reading from the diagnostic mode. I found they do not match. When the digital reading reaches 78 degree C, the needle already reached the dead center. Continue driving, the digital reading can reach about 94. But the needle still stays dead center. So it appears to be me these two readings are from different sensors? And there seems to be a block that prevent the needle from swinging further right?

I have changed almost everything recently, except the temperature censor on the lower radiator hose. Would that be the cause?

In effect you have discovered that you are driving an e46!
All of them operate the way you described.
The OBC temp reading is accurate, but the temp gauge is not actually a temperature gauge, but an idiot gauge. Might as well have an idiot light instead.
The gauge is not analog, but in effect operates in damped steps. That's why it's not a great thing to use to monitor engine overheating when you blow your ET or whatever else. It lags while you relax and let your head overheat and warp.
Good going BMW.

I believe the sensor in the hose is the temp sensor for the electric cooling fan. So I'm been told.

Originally Posted by Stinger9

It lags while you relax...

The problem is not it lags... It never goes past dead center, even after hours of driving....

So from 78C to 94C makes absolutely no difference in the needle position seem ridiculous. But I also see people claim their needle goes to the red zone. I wonder what the actual temperature on their cars at that moment? Must be very high!

Originally Posted by TonyJ

The problem is not it lags... It never goes past dead center, even after hours of driving.... So yours is calibrated a little off
So from 78C to 94C makes absolutely no difference in the needle position seem ridiculous. But I also see people claim their needle goes to the red zone. I wonder what the actual temperature on their cars at that moment? Must be very high!

Needle will go into the red zone. Warning seems to come too late for some whose head is warped by that time.
Maybe a little sign at the far right portion of the gauge should read "Head Warped"?

Hi all,

Just bought my old (1997-8, 6-cylinders & 95,000 kms on the clock), 323i over here in the Hong Kong heat - though 'tis beginning to cool slightly as we slip towards the winter months...

Anyway, just this Cooling System guide is worth the entrance fee (what's that? It's free to join? Yippee...!), so I'll be poring over the details within after changing plugs & oil & basic stuff like that. I foresee many happy hours of oily-fingeredness on the horizon - and you seem to have some real 6-pot gurus on this forum...

Many thanks, in advance.

Autolycus,
Hong Kong.

make sure you post pictures of your hong kong e46. i've never seen one! 97 too.. wow. that's early. welcome to the forums and +200 MP FOR POSTING YOUR FIRST POST IN MY COOLING THREAD AND TALKING ABOUT COOLING MAINTENANCE AS A FIRST PLAN!!!!
This qualifies for a free in person cooling consultation. But I'd need a round trip plane ticket and a place to stay!

I've been in HK a couple of times - where on earth do you find space to DIY in HK?

Love HK!

Btw, well worth it to buy Mango that ticket - will save you $1000s later!

-G

I did my expansion tank last weekend.
Removing the number 6 clip on the bottom of the tank goes a long way to removing the tank....lol
I had no problems actually removing the tank. It came right up.

I was rechecking things and I found that the sensor is not properly installed. I thought I did it right but when I felt underneath it was loose.

I think I remember twisting it to remove it, but when I got under the car and tired to twist it did not respond.

Surprisingly, it is not leaking....

What is the best or should I say, the proper way to install the temperature sensor ?

You definitely stick the sensor into the bottom of the expansion tank and turn it (clockwise?). Can't remember off hand, maybe someone else will chime in, but it definitely has to be turned to lock in place.

It's been a while but IIRC it should definitively lock into place. it should probably be pointing straight back towards the car. i can check mine if you'd like.

Originally Posted by moiz21

You definitely stick the sensor into the bottom of the expansion tank and turn it (clockwise?). Can't remember off hand, maybe someone else will chime in, but it definitely has to be turned to lock in place.

I went back under the car and pushed and tried to rotate it, but maybe I am pushing too hard ?

IDK...

I expected it to click or at least tighten . But nothing happened.

Originally Posted by E46Mango

It's been a while but IIRC it should definitively lock into place. it should probably be pointing straight back towards the car. i can check mine if you'd like.

I think mine was pointing straight back when I tried to put it in,,,,,,I am trying to visualize it.

But I was thinking it only rotated 90 degrees maybe it should rotate 180 degrees and maybe that is why it is loose.

HMmmmmmmmmmm, maybe I should rotate it around, and THEN try to insert it and tighten it.

you might loose coolant. if you do, re-add and re-bleed.

Originally Posted by E46Mango

It's been a while but IIRC it should definitively lock into place. it should probably be pointing straight back towards the car. i can check mine if you'd like.

If you were a REAL pal you would remove it and reinsert it so we all know for sure...................

JK....if I could ever get through this task I will feel like I have accomplished something...

It will be a list of proud accomplishments engraved on my tombstone.

Originally Posted by Raymond42262

...I was rechecking things and I found that the sensor is not properly installed. I thought I did it right but when I felt underneath it was loose.

I think I remember twisting it to remove it, but when I got under the car and tired to twist it did not respond.

Surprisingly, it is not leaking....

The water level sensor in the expansion tank goes into an air cavity that is separate from the coolant area of the tank. There's no seal on the sensor and you can remove it without any coolant coming out.

Originally Posted by Raymond42262

If you were a REAL pal you would remove it and reinsert it so we all know for sure...................

JK....if I could ever get through this task I will feel like I have accomplished something...

It will be a list of proud accomplishments engraved on my tombstone.

I don't remember but sounds like JOegr is correct. At any rate, if you want someone to remove and reinsert something, ask DMAX. he's always game for stuff like that!

Let us know if any coolant comes out. Curious to know.

Originally Posted by joegr

The water level sensor in the expansion tank goes into an air cavity that is separate from the coolant area of the tank. There's no seal on the sensor and you can remove it without any coolant coming out.

Your information supplied is exactly correct. The coolant level sensor just twists to lock in.
It is incorrectly called a temperature sensor in the previous posts. Unless he is talking about the transmission cooler thermostat.
This is why it is important to be rigorous about using the correct terminology.

Originally Posted by Stinger9

Your information supplied is exactly correct. The coolant level sensor just twists to lock in.
It is incorrectly called a temperature sensor in the previous posts. Unless he is talking about the transmission cooler thermostat.
This is why it is important to be rigorous about using the correct terminology.

I keep twisting and turning and it won't cooperate.

I was going to duct tape it in if I can't figure it out tonight.

Is there a problem if it hangs loose or falls out from the duct tape?

I have seen other posts that said it could hang loose. But I don't believe everything I read, especially when it comes to short cuts.