Bleeding cooling system...do not overfill...
 

...but if the bleeding procedure calls for you to fill the reservoir till water comes out of the bleed screw hole, isnt the float showing way over-filled then (6cyl M54)?

The bleed process is done with the motor running, and the bleeder is removing air from the res return line connected to the upper rad hose (highest point in the cooling system).

NEVER over fill the system.

The M54 requires the bleed process to be without the motor running. Heater on high, and lowest fan speed. Fill coolant with bleed screw open and continue to fill until you see coolant flow out of bleed screw. Stop filling it at that point and let the fan run until you do not see any more air bubbles. Close the screw.

I then start the car with the cap off and if the coolant level starts to go down I turn the car off and restart the procedure. If the level does not go down I put the cap back on and turn the fan to the highest setting and run the car till it hits operating tem ( and I have lots of heat coming out). Let the car cool and check your level.

I was done in 15 minutes tops with my e46 m54. No air and the coolant level did not go down.

It's been several years since I did the bleed process on a 6 cyl BMW, my bad.

To be honest... I've never had a problem bleeding an M54. I typically fill the system. Heat full, fan full, and leave the fill cap off. Start the car and top off coolant until float comes back up. Close fill cap... let car continue to run until up to temp. After it reaches full temp... crack bleed screw until no more air bubbles come out and heat in the car is blazing hot. Finally, let the engine cool, top off system, and you're done. :thumbup:

I've been debating whether to do the water pump myself preventatively - I don't hear any bearing noise from it, but don't want to let it fail either - I was going to buy an extra gallon and mix it up so I can crack the radiator drain and "flush" the system with some of the fresh coolant once I button everything up.

Then that opens up the well should I do the radiator hoses, expansion tank, and thermostat while I'm in there, and I know these parts were replaced at least 6-8 years ago, the water pump is original -

I have a cold belt squeal on startup so I may be doing the idler and tensioner pulleys and belts anyway, might want to just do it all at once -

And then I'm sure I would have an OFHG leak about a year later LOL

RB my original water pump went 260,000 miles before it ever leaked. I always stuck with BMW coolant though, with the addition of 12oz of Redline WaterWetter after any cooling system service was performed (Definitely helps deal with the Texas heat). I don't let any of the hoses go past 150,000 miles, but that only take me 6 years to do, so you're probably okay on those items for a little while longer. The tell-tale sign on those is the plastic connectors starting to look brown instead of black. I'd be most concerned with the age of your expansion tank.

You're 100% on with the OFHG situation - definitely easiest and most labor saving to do cooling system hoses, CCV and OFHG at the same time.

2002 X5 3.0 312,200 miles
2014 428i 22,800 miles

2004 325i sold at 123,600 miles
2001 325i sold at 66,000 miles

You have offered so much help and so many good tips on this forum that I think no one would have minded.

Yeah I'm at 5 years of ownership as of next month and I think he did the cooling hoses/system about a year or two prior - so I might be hitting the age threshold and not necessarily the mileage threshold (my miles are still super low at 90k)

How long until you did the OFHG? I didn't notice any leaks when I did my CCV in June of 2014, but will check it out again.

I just ordered INA idler pulley and tensioner pulley and a set of conti belts so it will give me a good opportunity to really inspect the tank, hoses, and spin the water pump and listen for noises - if anything needs addressing I'll just leave it open and get the parts -

My gasket went 176,000 miles just fine, then it turned into a gusher.