My 2013 had a low coolant warning light. It was going into the dealer anyway. Dealer said it was low, no problems, refilled, and I was on my way. I said "bs" it is a closed system and should not "just get low". 10 days later low coolant again. Clear crustyness around the tank and shock tower. Frustrated that my $195/hr dealer could not diagnose or find this problem I decided to try and tackle this issue myself.
$139 tank, 20 dollar cap and a jug of blackforest coolant. 30 minutes of work and 20 min youtube search.

Didn't think you would be scared of the work, but just so you know; the valve covers do not need to come off for intake, valley pan and coolant pipe removal/replacement.

Well it looks like the coolant system didn't want the extra fluid I put in. Walked out to the car about 10 minutes after my wife got home to this.

https://uploads.tapatalk-cdn.com/201...adcf1d5818.jpg

It's leaking right from the junction above the bottom hose connection. So I'll be ordering expansion tank, cap, as well as that hose and whatever else looks applicable on realoem. Anything else?

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Good time to do WP and Tstat if they haven’t been done. Recommend HEPU water pump.

I think I'll just fix the current leak for now so we can get it back on the road. I'll find a nice weekend this summer to do WP and tstat. Appreciate the brand recommendation!

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You bet. Good luck with the fix!

If you're doing the coolant transfer pipe, it absolutely means you should do the water pump at the same time. Age and mileage says you should also replace every hose attached to the pump as well.

If you do the coolant expansion tank right away, replace the hoses for that at the same time. Keep in mind that if you ever remove a recently replaced hose for future repair, you should change the O-rings. Not sure if you can get these from BMW, but full sets are available on eBay. If you open the plastic coolant drain at the bottom of the radiator, have another plug on hand as well; again age and mileage. (It too has an o-ring seal.) Don't be surprised if it breaks when you try to remove it.

Again age and mileage, (mostly mileage,) plus your oil consumption; you probably need to do the valve guide seals. To confirm, idle the car for five minutes. Then mash the gas. If you see a massive cloud out the exhaust, it means the valve guide seals are shot. The only other thing than can cause this is if your CCV is not functioning correctly. At this mileage, most people have replaced this already. Biggest culprit is the rubber membrane in the valve on top of the valve cover, but the hoses do get clogged with mayonnaise if you do a lot of short trips in cold weather. To diagnose this more exactly, you can hook up a smoke machine to the oil cap, (I have a blue rubber Snap-on Blue Point smoke machine adapter that stretches nicely over the oil fill). Remove the intake elbow and plug the intake. (Most smoke machines come with a set of various sized yellow plastic disks just for this purpose). No smoke should come out. This might also detect a valve cover leak, (common), but you'll be doing those gaskets anyway if you do the valve seals.

I do agree that as others have said, the valve guide seals and the valley pan have very little overlap unless you plan to pull the motor. Doing both jobs, it might be worth it. Also, if you have access to the back of motor, you can use the original factory coolant transfer pipe, saving you $500 or so vs the AGA pipe. Not to mention the grief of cutting out the old pipe. It will make the valve guide seal job much easier as well, as several of the valves seals are REALLY hard in terms of access, (not impossible, just hard.) It's also very tricky to remove the valve covers on these cars without breaking anything. Both jobs can absolutely be done while the engine is in the car, but pulling the motor at your mileage can be a great opportunity to address a whole array of issues not discussed as well that are common to this engine, (like oil leaks from the front upper covers, oil cooler fittings etc.)

If you decide to do the valve guide seals, I do have the AGA tool kit for rent in the For Sale forum, send me a message.

My picture of the leaky upside down coolant tank above. Crack was in the side, above that fitting that is wet on yours.
Do your youtube searches. The top hose has a little slip clip that you lift up and unplug the hose. The bottom hose is similar, but you can't @#$%!@#$ see it. I eventually got it, along with some foul language. 15 minutes of fishing around and 2 minutes to reinstall it.
Get a tank, parts guy recommended a new cap. (do you want fries with that)
My old one looked fine, but why risk it. I also buy my socks in pairs.
And way too much extra coolant. But i figured, if I did something wrong and had to do it over, I would have ample supply.

So I bought the tank, bottom hose, cap, and 2 gallons of undiluted coolant. Bavauto didn't have the top hose. I already have at least another gallon of undiluted coolant from some work I did on the E36 earlier this year.

Again just trying to do this quick and dirty. Over the summer I'll do a full flush and WP/t-stat change. I also want to do trans fluid change and seals, diff fluid changes, and transfer case fluid change so I'll just plan on having the whole car up in the air.

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I would also highly recommend you get a 1.4 bar cap (OE BMW, part #: 17117639020, nothing else). If you stick the 2.0 bar cap back on a cooling system that hasn't been serviced for a long time, you'll accelerate the deterioration of other weak spots.