COOLING SYSTEM GUIDE

This post is for you if you just purchased your E46 and/or have more than 75,000 miles on your current cooling system. The E46 is among certain BMW models that are known to to suffer from cooling-related failures, often times catastrophic due to warping the engine block. The 6-cylinder in your...

www.e46fanatics.com

 

Most of us get genuine BMW for the quality.

BMW Engine Coolant Expansion Tank - Genuine BMW 17117573781

BMW Engine Coolant Expansion Tank - Genuine BMW 17117573781

www.fcpeuro.com

 

A 1.4 bar coolant cap will help a lot in them not exploding. OEM 17111742232. Also alleviates a lot of stress on the rest of the cooling system

Also make sure you’re not filling coolant all the way to the top. It needs empty space in the expansion tank to expand, I like to keep mine just above the minimum mark.

 

Also make sure you’re not filling coolant all the way to the top. It needs empty space in the expansion tank to expand, I like to keep mine just above the minimum mark.

This. Went thru tanks annually for several years before understanding the gauge. When overfilled, gauge only shows "max". At present, five years on Rein tank by only filling to minimum. Air gap is key to compressibility under thermal expansion. Enjoy!

 

Another vote for OEM and a lower pressure cap.

I went with the GAS (GAS 1.2 Bar Coolant Cap | German Auto Solutions) cap because it's pretty too.

 

Anyone have any thoughts on the Nissen one on FCP? also +1 on the lower pressure cap as I believe its the only reason my expansion tank is still in one piece as it seems to be leaking at the seams.

 

Anyone have any thoughts on the Nissen one on FCP?

The Nissens one is made in China, so that’s a no-go. They maybe bought the Nissens naming rights for it.

 

Expansion Tank - OE BMW - FCP is trustworthy. No other way to go. When the tank blows, you get towed home.

This is a link to an e38/e39 OE vs aftermarket compare - Timm is good. It's not e46, but I think much is applied

 

Genuine is best but I get some like to save money and go aftermarket.

Only aftermarket exp tanks I’d use are Mahle or NRF.

 

Modine used to be the go to brand, if you didn't go OEM, but they seem to have dried up.

 

I was going to try my luck with a nissens one and see how it goes.

 

I have a nissens its been about a year no problems, it was recommended at that time.

 

When you could get a Modine, they were what BMW was marking up and putting a sticker on.
Now, you can still get them, but only from BMW. And yup, they still say Modine.
oh-JEZUZ! That was about a hundred last spring. Now it's almost $200!

Mahle aftermarket has been Fabrique au Chine for several years, now.

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Genuine BMW expansion tank & genuine cap, correct filling quantity and bleeding will ensure years of trouble-free service.

 

The Nissens one is made in China, so that’s a no-go. They maybe bought the Nissens naming rights for it.

Nissens expansion tank is chinese crap. Avoid it.

BMW Engine Coolant Expansion Tank - Nissens 17117573781

BMW Engine Coolant Expansion Tank - Nissens 17117573781

www.fcpeuro.com

 

Only aftermarket brand would be Modine if you can still get one. As other have said. Go with genuine. The consequences of an expansion tank failure can be catastrophic.