Remember... "topped off" means the flat is just level with the top of the can when cold.

if you put too much, I will 100% guarantee you will be buying a new coolant reservoir!

If you're losing coolant - it's possible it's because of a leaking valley-pan which is a much better scenario than a head gasket or the coolant pipe.

I replaced the valley pan on my 2005 4.4 this March. Previously I was topping-off with coolant twice a week. The leak wasn't obvious because most of the coolant was evaporating on the hot engine before it hit the ground. It wasn't until I bought a cooling system pressurization kit (harborfreight - about $70) that I figured out it was the valley-pan.

I also had a leak in the cooling system up by some plastic valve thing close to the radiator


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Yikes! You bought this without a PPI?

What's a PPI? Pre-purchase inspection?

Yes I did. I am pretty mechanically inclined (or at least I tell myself that) except for BMWs apparently haha.
This is my 10th vehicle and I have never had major problems on any other vehicle I've purchased.
Anyways,

I will keep an eye on how long and how many kms it takes between reservoir topups and go from there

Don't let em scare you... he obviously doesn't even know how to pop the hood on his ride

:nanana:

So here is Mike's comments, that I'll take liberty to paraphrase a bit (and I'm not responsible for typos!).
"BMWs are incredibly sensitive to operating fluids, including coolant. I've always felt this is due to the metallurgy used in the engine construction, but there is no way to know for sure. On neglected cars, aluminum oxidation builds up in various places within the engine, including on older models, between coolant hoses and aluminum fittings. That is the most obvious manifestation of aluminum oxidation. It causes the worst problems inside the sometimes tiny coolant passages of the cylinder head, where it can act like hardening of the arteries, restricing or even cutting off the supply of coolant to various parts of the cylinder head. This sometimes presents itself as phantom overheating with no known cause, though more often than not the cylinder head gasket blows before that.
I learned long ago that using phosphate free Original BMW anit freeze mixed 50-50 with distilled water and changing it every 2 years, of even four years on hotter running OBD-II modles essentially eliminates aluminum oxidation. The cars I mantain don't blow head gaskets or have cronic overheating problems. ......................."
again, credit to Bimmer Magazine and Mike Miller
And some documents. Take your time to digest it, then make your decision what's worth more: save a few pennies, or keep the car long term.

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