Reddit mentions: The best automotive engine coolant recovery kits

I just replaced the tank on my '05 R53 MCS two weeks ago. It was leaking all along the seam where the two halves come together. I'm sure I lost a bunch of coolant before I noticed it. The coolant was just bubbling out & never hit the ground, so it was hard to pick up on. I replaced it with this one from Amazon: https://www.amazon.com/gp/product/B00SKHSYEE/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

It's exactly like the OEM one. I figured that since the OEM tank lasted this long, I'd stick with the plastic. There are a couple of aluminum ones out there, but I didn't see springing the $100 for one - I'd rather spend that on a new supercharger pulley, or a new air intake assembly.

The replacement process is one of the only easy things I've done on my Mini. One bolt and 2 hose clamps is all that's holding it in. Done in about 15 minutes. Have fun!

EDIT: a word

Usually Amazon has pretty good deals on surge tanks.

Never use stop leak products, this will not cure your problem and cause clogging issues in various cooling system passages in a Northstar.

I ordered everything off amazon and did my thermostat, water pump, expansion tank, also on the automatic cars (like mine) there is another thermostat on the bottom of the expansion tank when you remove it, which most likely broke when your tank exploded

I also snapped off the drain screw/plug on the bottom of the expansion tank when switching it over...so I filled er' up with coolant, only to realize the MF'er was busted ever so slightly, so coolant was flowing through the expansion tank like taco bell does to me. So I replace that too for under $5.

This is a fairly easy job to DIY, the only thing you need to worry about is the 32MM wrench to take off the fan on the automatics, other than that, most of the tools are just the 14MM or 16MM sockets and some torx screws. If you are working on your E46 you should have a torx set, and a metric socket set. I did not do all the hoses though when I did mine as they felt and appear to be in decent condition.

[thermostat] (https://www.amazon.com/Stant-14602-Thermostat-Housing-Fahrenheit/dp/B000C822YM/ref=sr_1_1?s=automotive&ie=UTF8&qid=1487609776&vehicle=2003-31-176-20--1-6-6-7308-171-1-1---1-0&sr=1-1&ymm=2003%3Abmw%3A325xi)

[expansion tank thermostat that sits on bottom of expansion tank] (https://www.amazon.com/B7583-17111437362-Cooler-Thermostat-Housing/dp/B00BOIVI76/ref=pd_rhf_se_s_cp_7?_encoding=UTF8&pd_rd_i=B00BOIVI76&pd_rd_r=WV5225HSC9FA4W0BJ1FB&pd_rd_w=uAVgO&pd_rd_wg=nUSHN&psc=1&refRID=WV5225HSC9FA4W0BJ1FB)

[expansion tank] (https://www.amazon.com/Radiator-Coolant-Reservoir-Expansion-Quality/dp/B008564ZQG/ref=pd_bxgy_263_2?_encoding=UTF8&psc=1&refRID=9S8V0595SD0VV6X1BPVX)

[water pump with metal impeller] (https://www.amazon.com/URO-Parts-11-527-799/dp/B0066TLWGU/ref=pd_sim_263_21?_encoding=UTF8&psc=1&refRID=S1N6T6G260SVYS2YNMY1)

[32mm wrench for fan] (https://www.amazon.com/Clutch-Wrench-Water-Holder-Removal/dp/B017VLLQ6M/ref=pd_bxgy_263_3?_encoding=UTF8&psc=1&refRID=513EA9TG3QARCWSMJ554)

So for ~$150-$160 you can re-do the cooling system, if you want to do hoses as well, you are looking at another $50-$75

Literally 2 bolts and two hose clamps. They leak at the seam. Your cap looks like it's leaking with that spray out at the end. It's literally $25 and the tank comes with a new cap.

Amazon link

There is a cap shown in the parts diagrams. I think the cap is there so if you hit a bump or parked at an extreme angle the coolant would not piddle out, but if it overheated the cap would just blow off.

https://www.amazon.com/Coolant-Reservoir-Recovery-TO3014126-1648028080/dp/B00I15ASI0

I would suggest some generic rubber cap.

https://shop.advanceautoparts.com/p/dorman-help-black-rubber-vacuum-cap-assortment-41050/5012821-p

Dorman 603-383 Coolant Reservoir https://www.amazon.com/dp/B00NF1QZO6/ref=cm_sw_r_cp_apa_i_AivODb16EP5QD

Aluminum Coolant Reservoir Tank w/ NEW 16 PSI Cap | Fits 02-06 Mini Cooper S R53 05-08 Convertible R52S https://www.amazon.com/dp/B0166465KC/ref=cm_sw_r_cp_apa_i_Qa2ACb7AJRG0P

Sorry been off Reddit the last few days. Here's what I have.

Low Coolant.. just happened to me.
BMW 82141467704 Coolant / Antifreeze https://www.amazon.com/dp/B014MEBR3I/ref=cm_sw_r_cp_api_i_.GWCCb8NS6VE5

Dorman 47016 Coolant Service Kit https://www.amazon.com/dp/B000DCO58S/ref=cm_sw_r_cp_api_53RXAbGW2WSV5

The heater hose is a high point coolant system. The trick is to remove air binding in cylinder head. Install add coolant slowly venting from splice. Stand on bumper to see if you can shake the bubbles out. Carry water with and every time you drive and return to truck. If not cool..put a heavy bath towel over rad cap !!WARNING HOT COOLANT WILL SPRAY UP IN YOUR FACE!! Hence heavy towel. So make sure it is somewhat cool! Put rad-cap in center of towel open cap vent a bit at a time till no pressure spurts out under bath towel. ad coolant. Repeat as air moves to upper volume of radiator over course of week.

A pin hole leak may be in your heater core and you’ll need to stay ahead of it each week monitoring coolant in rad and htr core splice. Replacing htr core is a laborious task.

Throw some CLR in there for a while, shake the hell out of it occasionally. Rinse and repeat as necessary.

Or just cut to the chase and buy a new bottle: Dorman 603-305 coolant reservoir bottle - $22.47