expansion tank cap improvement

[kenslicktop]

Hi there,

Wondering if anyone has done this before.
The premiss is to reduce the pressure on the cooling system.
Replacing the 2.0 bar cap with a 1.4 bar cap.
I did this on my e46 330. I replaced it with a e30 1.4 cap.
The only e90 1.4 bar cap I've found is for a 335i.
Looks like it should fit.

https://www.ecstuning.com/b-genuine-...p/17117639020/

There's also a Rein brand at FCPeuro for a few bucks less. I've used rein
products on my other cars.


What do you think??

[amrazM]

I don’t think it’s necessary, the cooling system in our cars are pretty robust compared to some of the other models.

[wyatth]

Why would this be an improvement?

[kenslicktop]

The theory is it puts less pressure on our wonderful cooling system. Like the expansion tank.
I know the M has better quality parts in many areas. But, BMW cooling parts have always
been crappy
On my previous bmw's I always replaced the cooling system every 75k or so.
You guys with higher milage cars, have you done preemptive cooling system updates?
Or just wait until stuff fails?

[roastbeef]

there isn't currently a problem to address.

[kenslicktop]

thanks for your thoughts

[Solo_M_Tech]

Reducing the pressure in the system also reduces the coolants boiling point. Increasing the likelihood of overheating and coolant loss due too overflow.

You're addressing a non-issue with a bad idea.

[Redd]

Yeah I was wondering why you would want to make it more likely to boil the coolant?

[Mvy]

Originally Posted by kenslicktop

The theory is it puts less pressure on our wonderful cooling system. Like the expansion tank.
I know the M has better quality parts in many areas. But, BMW cooling parts have always
been crappy
On my previous bmw's I always replaced the cooling system every 75k or so.
You guys with higher milage cars, have you done preemptive cooling system updates?
Or just wait until stuff fails?

I have but I like to be proactive on replacements and not wait for a full failure. My expansion tank started to leak so replaced (the OEM replacement part was slightly different I noticed). I also replaced the radiator (using stock) because I added an SC and was in there anyway. This was done at 61k, 7 years of age.