[li04am]

my parents are convinced that me using manual mode in my 320i touring caused the expansion tank to explode. it's already had an expansion tank replacement from the previous owner so this is at least the cars third expansion tank. is it possible that my use of manual mode blew up the cooling system?

I don't think so but I want some peace of mind.

thanks,
Liam

 

[dmax]

It wasn't the manual that did it. It was a cooling system/owner failure. You didn't overfill the ET did you? Replace the cap when you replace the ET, as it should vent excess coolant if there is any, but you do need air in the ET, otherwise it's not an ET.

 

[MrMCar]

No correlation other than higher engine speeds and the increased need of the cooling system to handle such.

 

[dmax]

No correlation other than higher engine speeds and the increased need of the cooling system to handle such.

...and now I'm thinking a stuck thermostat. OP...if you were revving higher rpms, the therm should open fully to keep engine cool. Maybe replace the therm while you're doing ET?

 

[nkalfov]

My expansion tank is changed 15k miles ago. Yesterday I’ve found a crack in the connection of the expansion tank and the radiator. The mechanics say it is because whoever mounted the current tank was not gentle with the radiator. However, before the crack I did drift in the snow in manual mode. Not sure if it is related.

 

[li04am]

It wasn't the manual that did it. It was a cooling system/owner failure. You didn't overfill the ET did you? Replace the cap when you replace the ET, as it should vent excess coolant if there is any, but you do need air in the ET, otherwise it's not an ET.

...and now I'm thinking a stuck thermostat. OP...if you were revving higher rpms, the therm should open fully to keep engine cool. Maybe replace the therm while you're doing ET?

no the thermostat is fine. I was watching temps and then the check coolant light came on and my temps shot up also the old et has big old crack in it

 

[markusmarkus]

My expansion tank is changed 15k miles ago. Yesterday I’ve found a crack in the connection of the expansion tank and the radiator. The mechanics say it is because whoever mounted the current tank was not gentle with the radiator. However, before the crack I did drift in the snow in manual mode. Not sure if it is related.

View attachment 941441

The radiator in early E46s had a weak spot where the pipe that attaches to the expansion tank would crack. The only solution was to replace the radiator. The consensus here and on other bimmer forums is that the cooling system need to be overhauled every 100k miles/160kms. The installation of aftermarket cooling system parts is strictly verboten.

 

[li04am]

The radiator in early E46s had a weak spot where the pipe that attaches to the expansion tank would crack. The only solution was to replace the radiator. The consensus here and on other bimmer forums is that the cooling system need to be overhauled every 100k miles/160kms. The installation of aftermarket cooling system parts is strictly verboten.

I think mine still has the original radiator. it's at about 220k kms

 

[MrMCar]

Something that's harder to witness. (maybe the reason, maybe not?)
There are two temperature sensors for the cooling system in general:
1) on the side if the cylinder head. This is for instrument cluster display (both the gauge and mode 7 of the cluster) and the DME to adjust fueling tables.
2) the other one is located on the neck of the lower radiator hose. For use by the aux or main puller fan and it actually is used in some Vanos calculations.

It's possible that your radiator is old. tired and no longer working effectively. Tantamount to arterial sclerosis.
In the above scenario; the engine coolant runs normal, however the radiator (not working well?) has much higher than normal temperatures.
This would see a substantial increase in cooling system pressure.

Lower rad temp sensor viewing is only available with higher level scan tools.
A Hypothesis....

 

[nkalfov]

The radiator in early E46s had a weak spot where the pipe that attaches to the expansion tank would crack. The only solution was to replace the radiator. The consensus here and on other bimmer forums is that the cooling system need to be overhauled every 100k miles/160kms. The installation of aftermarket cooling system parts is strictly verboten.

I wasn't the owner when the expansion tank was changed So you mean I must buy BMW OE radiator? I shouldn't swap it for MAHLE BEHR Premium Radiator? Before discount the first is around 362 USD and MAHLE is USD 277.92. There are cheaper, of course, I have no idea should I use them, I guess not. The previous owner changed the expansion tank from OE to MAHLE. What about Behr Hella Service PREMIUM LINE?

 

[nkalfov]

I think mine still has the original radiator. it's at about 220k kms

Mine is near 240k km and is the original. I need change it, though

 

[MrMCar]

I wasn't the owner when the expansion tank was changed So you mean I must buy BMW OE radiator? I shouldn't swap it for MAHLE BEHR Premium Radiator? Before discount the first is around 362 USD and MAHLE is USD 277.92. There are cheaper, of course, I have no idea should I use them, I guess not. The previous owner changed the expansion tank from OE to MAHLE. What about Behr Hella Service PREMIUM LINE?

Mahle/Behr is almost ALWAYS Chinese. NO
Get the Nissens. A product made in the EU and superior to anything else on the aftermarket.

 

[nkalfov]

But the Nissens in around 100 USD. Its one of the cheapest. Maybe I'll go for the OE.

 

[M.Blacktree]

Filling the cooling system in the E46 is counterintuitive. You actually need airspace in the expansion tank, so the coolant has space to expand. If you're going to be driving "sporty", you may actually want to underfill the tank, to provide more expansion space. So for example, you would fill it to the minimum coolant level, instead of the maximum. I started doing this with my E46, because I race it and I don't want the tank to pop.

Filling to the minimum coolant level will not affect cooling system performance. But if the expansion tank explodes, that WILL affect cooling system performance.

 

[nkalfov]

Could've I done this? I went drifting on snow on 1st and 2nd gear on 4k to 6k RPM. Then I was exited and I was starting at first gear on traffic lights, going up to 60 mph on 2nd gear, until it shifts to 3rd gear (automatic starts at 2nd gear). The car is very responsive on higher RPM I had fill the the antifreeze to the max, because I did change the termostat last month.

 

[mrkprsn]

But the Nissens in around 100 USD. Its one of the cheapest.

I put one of these in a few years ago. Have had no problems and the fit was perfect.

 

[MrMCar]

Do as you wish.

There was a time about 10 years ago when Behr was making the changeover to full Chinese production. There was a shortage of quality (EU made) radiators.
There were however plenty of Nissens radiators available. Having only used the Nissens brand a few times in the past, I called a friend of mine (BMW shop owner in Phoenix Arizona) and asked about the Nissens.

He said he prefers the Nissens brand 2 to 1 over the Behr. product.
If anybody knows about heat & cooling systems failures, Phoenix does!

I've used them ever since without any (ZERO) failures.

 

[_Tim_]

But the Nissens in around 100 USD. Its one of the cheapest. Maybe I'll go for the OE.

Go for the Nissens. In first instance I replaced most of the cooling components with aftermarket stuff. Mahle, Hella/Behr and Nissens. Only thing that hasn't given me trouble is the Nissens radiator. The rest has been replaced with OE.
Also last time I checked the OE radiator was about 4 times the price of the Nissens.

 

[nkalfov]

Yes, I'll go for the Nissens. A friend of mine told me some of them are made near a town I lived in Denmark for a few years, which grabbed my attention.

 

[e46betterthannoe46]

my parents are convinced that me using manual mode in my 320i touring caused the expansion tank to explode. it's already had an expansion tank replacement from the previous owner so this is at least the cars third expansion tank. is it possible that my use of manual mode blew up the cooling system?

I don't think so but I want some peace of mind.

thanks,
Liam

My two cents, DO NOT BUY DAYCO EXPANSION TANKS. The adrad one I've got is going strong. A question is what colour coolant is in your system? P.s I am blessed with a factory manual so our expansion tanks are a little different.