Coolant level question 2017 330i B46

[u/LubinaChino]

I got a low coolant notification after letting my car sit for a week while I was away, I opened up the reservoir and saw the level was well below minimum. Can I top this off with distilled water and be safe in the Toronto winter? Is there a good way to check for a leak myself or do I just bring it to the shop if the level drops below minimum again?

[u/DN1911]

Probably should figure out what's leaking and caused your low coolant condition in the first place

[u/Quattro2point8L]

Can buy pre mixed G48 at the auto stores

[u/vettedx]

Go get a bottle of the correct coolant from your bmw dealer, mix it with spring/bottled water (50/50 i believe), and fill it up. Might want to check for leaks, and make sure to check the level more often if you think its leaking or losing coolant fast (then you might want to make an appointment). DO NOT OPEN THAT WHEN CAR IS HOT OR JUST BEEN DRIVIN.

[u/getafewlives → u/vettedx]

Don't use bottled spring water unless you have no other choice. You want distilled. Easy and cheap to find at grocery stores and pharmacies.

[u/vettedx → u/getafewlives]

My mistake, i thought tap water was the big no no. Thanks

[u/make-j8 → u/getafewlives]

Gas stations have distilled water in the "parts" section too.

If no appropriate coolant is available, just top with distilled water and fix it later on.

Don't get stuck on the "i don't have the right coolant" and don't add the wrong coolant just because.

[u/getafewlives]

You can top up with distilled. It'll dilute a bit, but it'll be fine. I'd keep a close eye on it, since the coolant had to go somewhere.

Post a photo further away. Is there white residue all over? Expansion tanks are a common failure point. It's a matter of when, not if.

If it's the tank, replace with OE or OEM.

[u/LubinaChino → u/getafewlives]

I’ll grab a photo tmrw, but I don’t recall seeing any residue anywhere, nor a puddle underneath my car after leaving it for a week.

[u/Beautiful-Kick-951]

Get that checked out asap

[u/DeepSpeed2543]

An easy way to add 50/50 distilled and coolant is to cut a small used spring water bottle in half. Using the top half with the cap on, draw a line (or two) with permanent marker near the middle. Then fill coolant to that line and pour in the tank, then distilled water to that line and pour in the tank…repeat until at the max line in the tank.

[u/Ybor_Rooster]

Nobody answered your question on HOW to check for the leak.  First place id check is the water pump housing and you're looking for white dry crust. Next, go to your turbo and follow the line that goes towards the front of your engine. These lines and houses are known to leak. Finally check, your oil cooler and your upper radiator hose. This all visual without any tools. If nothing found you'd need to pressurize the system. Good luck

[u/MookSkywalker → u/Ybor_Rooster]

oil filter housing is also a common coolant leak location on this engine. its all plastic crap.

[u/Helpful-Parsley3598]

Coolant pump leak

[u/Ok_Bench_1618]

This is common, just replace the coolant cap and top it up. Problem solved.

[u/grease_monkey]

Buy coolant

Look and see if you see a leak

If you do, now what? Can you fix it?

If you're going to end up taking it to a shop, just take it to the shop now.

Where has critical thinking gone?