Draining cooling system without turning engine on??

[bkirk]

I have just finished replacing the front shocks and coils (Bilstein B4's - Touring for the inquiring minds) and now need to move on to the cooling system refresh. In another post you may have read that I managed to crack the water pump pulley while trying to free the fan clutch from the water pump. As a result, I'm unable to start the engine to follow the usual procedure of draining the system.

My plan at this point is to do the following:

1) drain the radiator using the drain plug
2) drain the engine block by removing the block drain plug
3) remove the upper and lower radiator hoses
4) remove the radiator itself

At this point, I planned on removing the fan blades from the clutch, remove the cracked pulley from behind the clutch (still not able to be removed) and finesse the water pump bolts and remove the pump and clutch together. Later in the project, the coolant expansion tank and associated hoses and components will be removed.

My question is this. Once I finish the cooling system refresh, along with CCV and Disa rebuild, what is the best way to go about re-filling the cooling system so that there isn't any trapped air? With the engine unable to be started, I'm concerned that I will not have fully drained the heater core.

[ProductUser]

As to your heater core question, see post #1 and#2 http://www.bimmerforums.com/forum/sh...-and-questions

[bkirk]

As to your heater core question, see post #1 and#2 http://www.bimmerforums.com/forum/sh...-and-questions

Excellent thread, Thank you!

[Mark Bielick]

Filling the cooling system is easy with an airlift system. Pulls a vacuum on your entire system, which also allows you to see if there are any potential leaks before refilling. Then, once you verify no leaks, the system will suck the coolant into your system with no possibility for air entrapment (no air-no entrapment)

[bkirk]

Filling the cooling system is easy with an airlift system. Pulls a vacuum on your entire system, which also allows you to see if there are any potential leaks before refilling. Then, once you verify no leaks, the system will suck the coolant into your system with no possibility for air entrapment (no air-no entrapment)

Dumb question, could this system be used to drain the already full cooling system versus the drain plug and attendant mess on the garage floor?

[Mark Bielick]

Not designed to do that. It creates a vacuum using a venturi from the air from your air compressor. It cant suck fluids. The vacuum generated pulls the coolant into the system.

[BimmerBreaker]

Filling the system is easy, just fill it. Dont need any magic tools for it. Yours is a 1999 so
an M52TU which is self-bleeding. Top it up, drive it then make sure its still topped up the next morning.

[bkirk]

Filling the system is easy, just fill it. Dont need any magic tools for it. Yours is a 1999 so
an M52TU which is self-bleeding. Top it up, drive it then make sure its still topped up the next morning.

I guess I didn't realize that. I've read all about getting air trapped in the system and didn't want to happen. I guess I can return the device I purchased (but haven't received yet) to refill the radiator and cooling system.

IS there something different about the M52TU system from the others that makes the air trapped issue not a problem?

[BimmerBreaker]

The expansion tank sits above the engine on the driver's side shock tower on M52TU, M54 and S54 cars. So any air bubbles will find their way there instead of being stuck in the cooling system like on M52/S52 cars where the expansion tank sits lower, mounted to the radiator. Its still not a bad idea to do a bleed the first time its filled if you are draining the whole system - fill it with coolant, start it and have the fan on the lowest setting and heat on max to open the heater core to make sure that gets filled too. But dont overthink it on that car, drive it around a bit and the most important thing is to check the fill level the next morning, as the coolant fills the system it will drain the expansion tank and you want to make sure its above the cold/kalt fill line on the tank which on your car means to make sure the red float is sticking out the appropriate amount.

But those M52TU/M54 cars are 100x easier than the M52/S52 system everyone seems to struggle with... "Jack up the front of the car" is a common trick people use to try to make those M52's bleed easier. Jacking up the front raises the radiator-mounted expansion tank above the engine so air will naturally find its way to the top and theoretically make bleeding easier (Ive NEVER needed to do that on any of my M52/S52 cars for the record). The expansion tank on your car though is already higher than the engine. Jacking up the front of your car will make bleeding more difficult.

[bkirk]

The expansion tank sits above the engine on the driver's side shock tower on M52TU, M54 and S54 cars. So any air bubbles will find their way there instead of being stuck in the cooling system like on M52/S52 cars where the expansion tank sits lower, mounted to the radiator. Its still not a bad idea to do a bleed the first time its filled if you are draining the whole system - fill it with coolant, start it and have the fan on the lowest setting and heat on max to open the heater core to make sure that gets filled too. But dont overthink it on that car, drive it around a bit and the most important thing is to check the fill level the next morning, as the coolant fills the system it will drain the expansion tank and you want to make sure its above the cold/kalt fill line on the tank which on your car means to make sure the red float is sticking out the appropriate amount.

But those M52TU/M54 cars are 100x easier than the M52/S52 system everyone seems to struggle with... "Jack up the front of the car" is a common trick people use to try to make those M52's bleed easier. Jacking up the front raises the radiator-mounted expansion tank above the engine so air will naturally find its way to the top and theoretically make bleeding easier (Ive NEVER needed to do that on any of my M52/S52 cars for the record). The expansion tank on your car though is already higher than the engine. Jacking up the front of your car will make bleeding more difficult.

That makes a ton of sense. Thank you.

[rf900rkw]

I've been hammering on this for years in this forum. There are three totally different cooling systems in the Z3 line, each with it's own strong and weak points, each with it's own needed techniques. But some reason everyone wants to follow instructions written for a E38 740.

The M54 is very unique in that the water pump , while still in the same physical location, is plumbing totally to the head. Not to the block. Thus, when filling the system, you can't count on the coolanty runing into the block throught he waterpump. It does go through the waterpump, bu then it has to rise up to the head level before it can cascade down into the block. This leads to a lot of small pours as the last part of filling it up. Trickle, wait, trickle wait. Until the level quits going down. Starting the engine before it's full is dumb. Well, it';s dumb on any engine, but especially dumb on the M54 cause the first thing that will happen is the waterpump will air lock.

So bottom line, if you don't drain the block, it will remain filled (even through a waterpump change) and refilling is super easy. If you do drain the block, you then have to trickle fill it. The tendency is for people to pour in a bunch, then fire the sucker up. Don't. Make sure it's full first. M54. Don';t jack it up. Don't turn the heater to full, and don't start it.


On the air-lift thing. I have one. I haven't use it in years because it just doesn't work as advertised. It doesn' pull a total vacuum, only a partial. The best I've seen is 25 "hg, and that is on a commercial 2 stage 175psi compressor. A home 125 psi compressor will be lucky to pull 22"hg. That means the system still 25% full of air when you start the fill. .

[Mark Bielick]

Your airlift must not have worked as designed. Mine pulled just under 30Hg, which is darned near a vacuum. Used it three times on two cars, and never had a problem. I was able to pull the vacuum, hold it to test for leakdown, and fill the system without a single issue. I'm not saying everyone needs one, but it does work as designed.

[Andy Woods]

Randy is exactly right, of course. When I replaced the cooling system on my 2001 M54 I bought this big yellow funnel thing from Bavauto that attached to the cap opening on the expansion tank. Fit the big yellow funnel to the expansion tank, fill the funnel with coolant. The coolant trickles down into the expansion tank, radiator, head, and block. Keep filling the funnel until it quits trickling down. The funnel has a stopper in it with a handle that sticks up above the top of the funnel so when the coolant finally quits trickling down you can pull the stopper to close the funnel, then remove the funnel without spilling coolant.

After reading of all the horror stories about refilling the cooling system in these cars I was worried I would screw this up as I am a complete novice at this. But with the big yellow funnel I filled the system up using the slow trickle method and was successful without any airlocks. It's been almost two years. It worked perfectly for the M54.

[bkirk]

Randy is exactly right, of course. When I replaced the cooling system on my 2001 M54 I bought this big yellow funnel thing from Bavauto that attached to the cap opening on the expansion tank. Fit the big yellow funnel to the expansion tank, fill the funnel with coolant. The coolant trickles down into the expansion tank, radiator, head, and block. Keep filling the funnel until it quits trickling down. The funnel has a stopper in it with a handle that sticks up above the top of the funnel so when the coolant finally quits trickling down you can pull the stopper to close the funnel, then remove the funnel without spilling coolant.

After reading of all the horror stories about refilling the cooling system in these cars I was worried I would screw this up as I am a complete novice at this. But with the big yellow funnel I filled the system up using the slow trickle method and was successful without any airlocks. It's been almost two years. It worked perfectly for the M54.

Thanks, one big yellow funnel on order!

[ThatZ3Guy]

Not sure the differences between the coolant systems on the M52TU and M54, but I drained my coolant system by draining the radiator and then draining the block. Kiddy pool came in handy for the block drain. Refill was as others above described. Slowly fill the system through the expansion tank, then I followed the bleeding instructions from the Bentley manual. Went for a drive, let the car cool, check fluid and top off if necessary. Check periodically for the next few drives and then call it filled. I am not an advocate of running an engine with no coolant.

[318Paul]

It appears to me that if one removes any o-ring hose fitting, that one should be prepared with a new o-ring. I replaced coolant tank and the upper connection leaked when reconnecting the hose with its "quick-disconnect" fitting. I did lube it too. New o-ring did not come with my Febi tank nor are they called out with part numbers on Realoem. The challenge is to figure out the o-ring size before one needs it! There are several sizes. Does anyone know? The one at top that is leaking is the smaller of the two, looks like 16mm ID x 3.5mm thick?
2007 X3 3.0 N52

[vetfever]

Good info in here - Thanks Everyone

vetfever

[lpschafer]

[QUOTE=rf900rkw;30441010]I've been hammering on this for years in this forum. There are three totally different cooling systems in the Z3 line, each with it's own strong and weak points, each with it's own needed techniques. But some reason everyone wants to follow instructions written for a E38 740.

Is there a thread in this forum specifically for the S52? Please direct me to it. Thank you!

[BimmerBreaker]

[QUOTE=lpschafer;30510134]

I've been hammering on this for years in this forum. There are three totally different cooling systems in the Z3 line, each with it's own strong and weak points, each with it's own needed techniques. But some reason everyone wants to follow instructions written for a E38 740.

Is there a thread in this forum specifically for the S52? Please direct me to it. Thank you!

What about the S52 are you looking for?

[RayBallen]

My M44 is said to be the hardest to bleed but thankfully I've had no issues. But maybe because I filled the coolant through the upper radiator hose for two things.

1.) Didn't want the new water pump to spin dry

2.) The block is filled with coolant easily until it overflows to the expansion tank, leaving only possible air trapped in the heater core.

Heater works easily and gets hot full blast. I've learned this from E30 fellas.

[lpschafer]

[QUOTE=BimmerBreaker;30510141]

What about the S52 are you looking for?

Randy's post alluded to one or more threads regarding technique for draining, filling, and bleeding three different Z3 cooling systems. I would like to learn more about the S52 techniques.