[gbalthrop]

I'm looking for an easy, quick, SAFE way to Drain as much coolant as possible from block, in addition to draining radiator. I have questions for anyone who has found some shortcuts for getting coolant to drain from block, past the Thermostat. Here is the TIS Procedure, also copied in Bentley, which describes removing Lower Radiator hose from Thermostat Housing in last (5th) photo:
https://www.newtis.info/tisv2/a/en/e...-check/GZ99pmA

When I tried that when my car was 12-years-old, the hose coupler did NOT want to release easily, so I elected to simply drain the radiator and NOT risk damage to the hose or Thermostat by forcing the issue. Obviously that leaves 30% to 40% of the 9 quarts of coolant (total capacity) still in block.

QUESTIONS:
1) If that Lower Radiator Hose is disconnected from Thermostat, how much coolant will actually drain from block and how many hours would one have to wait? Isn't the thermostat closed when engine cool?
2) INPA will "Activate" the thermostat; can one SAFELY ACTIVATE the thermostat several times with radiator drained and plug still open, and thereby drain ALL/MOST of the coolant from the block?
3) Can one simply disconnect the Radiator Bypass Hose that runs from the Head to the Thermostat/Pump, and attach a water source to that hose, to expel coolant from the block/head, bypassing the Thermostat?
4) Is there any such trick that anyone has used in lieu of removing stuff underneath (other than radiator drain plug), for LAZY folks like me that would rather spend time thinking about shortcuts than removing, breaking, cursing.

I have obviously never changed my Coolant Pump or Thermostat, so have never gotten "up-close & personal" with them to figure out the exact coolant flow, or dissected a thermostat to see what its "backflow" rate/ restriction may be. Any first-hand knowledge from ANYONE who has done this and taken the time to think about how it actually works would be GREATLY appreciated.

George

[mainbearing]

I believe the thermostat is activated with a heating element, therefore I would not try to activate it with coolant drained. You might overheat the wax element, if that is how it works.

How about filling it with distilled water, run the purge procedure, then drain again. And maybe yet again? Then use BMW concentrate to re-establish 50% mix.

[smass]

+1 on just pulling the U hose in the back. This is low risk for your situation.

[mecheng77]

What about operating the water pump in INPA with the drain opened to circulate some coolant. Otherwise I'd op to fill and run the car with distilled water and then drain again

[6Inarowmakesitgo!]

Drivers side of engine block, under the intake manifold, there is a large torx headed bolt sticking out of it. More towards the front of the engine, that is the coolant drain for the block.

[Efthreeoh]

I pulled my previous post...

To check my DIY.

My directions were:

"To drain the coolant from the engine block you need to remove a few hoses from the water pump and thermostat housing. The BMW TIS procedure calls for removing the lower radiator hose that goes into the front of the thermostat housing. That hose has the funky BMW plastic coolant hose fitting and is a PIA to get loose. I chose to remove the u-shaped hose running from the back of the thermostat housing to the water pump and the hose from the block to the water pump (nothing really came out so you don’t need remove that hose). The hoses I removed use regular BMW hose clamps w/ 6 mm hex heads."

That said. As I recommended yesterday, go buy the Motive (i.e. brake bleeder company) BMW cooling system test fitting. It is a brass air hose fitting that is threaded to fit in the threaded bung for the BMW cooling system bleed screw used on most modern BMWs. You can load the cooling system with 16 PSI of compressed air to void the engine block of coolant. Net time I drain and flush coolant on one of my Bimmers, I pan on using that method.

But also, as I said yesterday, I have no worthiness to teach the Master

[Efthreeoh]

Originally Posted by 6Inarowmakesitgo!

Drivers side of engine block, under the intake manifold, there is a large torx headed bolt sticking out of it. More towards the front of the engine, that is the coolant drain for the block.

N52 does not have a engine block drain.

[6Inarowmakesitgo!]

https://www.realoem.com/bmw/enUS/sho...diagId=11_3731

#6 and 7.

Not a good “drain” as it is on the wrong side of the engine, but it is a port for the cooling jacket. My engine does not have a Allen socket, it has a large torx bolt with an aluminum crush washer.

[Efthreeoh]

Originally Posted by 6Inarowmakesitgo!

https://www.realoem.com/bmw/enUS/sho...diagId=11_3731

#6 and 7.

Not a good “drain” as it is on the wrong side of the engine, but it is a port for the cooling jacket. My engine does not have a Allen socket, it has a large torx bolt with an aluminum crush washer.

Yeah, not sure how many BMW inline 6 you've worked on, but that's not an engine block coolant drain plug. Not sure how you'd get a wrench on it since it sits under the intake manifold. When a BWM inline 6 has a block drain for coolant, it's on the right side of the engine block under the exhaust manifold.

The N52 does not have a block drain plug for draining coolant from the engine block. BMW's technical documentation states as such.

[gjm120]

Originally Posted by Efthreeoh

I pulled my previous post...

To check my DIY.

My directions were:

"To drain the coolant from the engine block you need to remove a few hoses from the water pump and thermostat housing. The BMW TIS procedure calls for removing the lower radiator hose that goes into the front of the thermostat housing. That hose has the funky BMW plastic coolant hose fitting and is a PIA to get loose. I chose to remove the u-shaped hose running from the back of the thermostat housing to the water pump and the hose from the block to the water pump (nothing really came out so you don’t need remove that hose). The hoses I removed use regular BMW hose clamps w/ 6 mm hex heads."

That said. As I recommended yesterday, go buy the Motive (i.e. brake bleeder company) BMW cooling system test fitting. It is a brass air hose fitting that is threaded to fit in the threaded bung for the BMW cooling system bleed screw used on most modern BMWs. You can load the cooling system with 16 PSI of compressed air to void the engine block of coolant. Net time I drain and flush coolant on one of my Bimmers, I pan on using that method.

But also, as I said yesterday, I have no worthiness to teach the Master

So putting pressure in the system negates the need to disconnect any hoses?

Is this the adapter?

https://www.motiveproducts.com/produ...iator-products

[Efthreeoh]

Originally Posted by gjm120

So putting pressure in the system negates the need to disconnect any hoses?

Is this the adapter?

https://www.motiveproducts.com/produ...iator-products

Yesser, that be it.

The cooling system pulls coolant into the t-stat using the water pump. The water pump feeds the engine block, so the hose that comes out of the engine block is fed by the water pump. If you remove the U-hose from the water pump, you are essentially opening up a drain from the engine block. Pressurizing the system from the coolant tank will pressurize the engine block and force the water out through the WP.

[6Inarowmakesitgo!]

Originally Posted by Efthreeoh

Yeah, not sure how many BMW inline 6 you've worked on, but that's not an engine block coolant drain plug. Not sure how you'd get a wrench on it since it sits under the intake manifold. When a BWM inline 6 has a block drain for coolant, it's on the right side of the engine block under the exhaust manifold.

The N52 does not have a block drain plug for draining coolant from the engine block. BMW's technical documentation states as such.

Owned BMW for a long time, have had 3, 5 , 6 and 7 series. I know that they usually put it under the exhaust on the right side.

I used a long extension with a swivel, took it out and coolant comes out.

[Efthreeoh]

Originally Posted by 6Inarowmakesitgo!

Owned BMW for a long time, have had 3, 5 , 6 and 7 series. I know that they usually put it under the exhaust on the right side.

I used a long extension with a swivel, took it out and coolant comes out.

At best, removing that bolt will drain some coolant from the cylinderhead. It's too high on the block and on the wrong side of the block to drain most of the coolant from the engine block water jackets around the cylinders if the engine is installed in the chassis. If the engine is on a stand, then I could see opening that bolt to drain any residual coolant from the block and head.

If it is an actual engine block coolant drain bolt, BMW would state as such in it's coolant drain procedure, which it doesn't. I'm not arguing the point just for the sake of arguing. I agree it's a bolt that opens the block cooling system, but I do not think it was intended as a coolant drain for the engine block. Maybe a drain for the head, but I checked the TIS N52 cylinderhead removal and it is not referenced there either. Based on it's position, I'd hate for a noobe to try and get that bolt out using a long extension bar and u-joint to reach it. It's an aluminum bolt, so if you drop it, I'd be a bitch to retrieve.

My suggested method(s) to drain the block are much easier and get more coolant out.

My 2 cents.

[6Inarowmakesitgo!]

Originally Posted by Efthreeoh

At best, removing that bolt will drain some coolant from the cylinderhead. It's too high on the block and on the wrong side of the block to drain most of the coolant from the engine block water jackets around the cylinders if the engine is installed in the chassis. If the engine is on a stand, then I could see opening that bolt to drain any residual coolant from the block and head.

If it is an actual engine block coolant drain bolt, BMW would state as such in it's coolant drain procedure, which it doesn't. I'm not arguing the point just for the sake of arguing. I agree it's a bolt that opens the block cooling system, but I do not think it was intended as a coolant drain for the engine block. Maybe a drain for the head, but I checked the TIS N52 cylinderhead removal and it is not referenced there either. Based on it's position, I'd hate for a noobe to try and get that bolt out using a long extension bar and u-joint to reach it. It's an aluminum bolt, so if you drop it, I'd be a bitch to retrieve.

My suggested method(s) to drain the block are much easier and get more coolant out.

My 2 cents.

I was personally going to install a coolant heater and have this be the outlet and have it draw from one of the heater core hoses.

Yeah, its definitely the wrong side of the engine to be an effective drain.

[Cali_MSport]

I had to flush my cooling system, block included (n52), because someone had poured a whole bunch of stop leak into the coolant. The issue was a crack in the radiator so I dont know why they thought stop leak would work. It was not near as bad as I thought it would be to remove it . I simply drained all the coolant that I could drain, filled it up with distilled water and ran the engine until it reached operating temperature (open thermostat). Once it was warmed up I pulled the bottom radiator hose (Already loosened, removed, and then put barely back on for easy removal) off of the radiator and inserted this plug I had made into the open end of the lower radiator hose. The plug was made with a t-shirt and duct tape and had an air hose going through the center of the plug. The air hose was fit with a blower and a quick shut off valve. So basically the engine is hot, you yank the bottom hose off the radiator, shove the plug into the open end of the hose an open the quick valve to blast air through the system. This forces all of the coolant/distilled water from the engine block. Do this a couple times and you'll see that your water is coming out clear than do it one last time to blast the water out so the when install your coolant it will be the right ratio of water to coolant. Easy to do this if you you have access to a decent air compressor that has a fair amount of pressure. Worked like a charm for me.

[mecheng77]

There is a feature in INPA to check wp speed deviation. Why not run this which turns on the wp for a couple of seconds

[TunafishE93]

Pulling hoses off while car is heated is dangers! The system is under pressure and will shoot hot fluids all over. If you are stuck under the car in this situation bad things can happen. I know most will know this but think that it still needs noted.