quick question about coolant flush

[bastianshaw]

Im flushing the coolant and it came out straight rust, im just undoing the radiator drain, draining, then filling it up with water(after it cools) do I HAVE to drain the block?

Wont the water pump "flush" the block and I can drain it out the radiator drain?

Im about to do the TB and want to get all this shit out before i replace the cooling stuff

[LateFan]

The block drain is easy - it's behind the rear exhaust manifold, big hex plug. Quite a bit of water comes out of the block when you pull this. I did both block and radiator last night in different combinations of open / closed / hoses off, in order to wash it around and out.

It's worth it if yours looks crappy.

[s14pwd]

Ya it will mix and dilute, but it would take more flushes your way to achieve the same effect as draining the rad and the block. When I first got my car I drained the Rad and the Block 5 times I think, filling with distilled water each time, running for 10min in between. Basically until the drained coolant looked like water.

[bastianshaw]

Ya it will mix and dilute, but it would take more flushes your way to achieve the same effect as draining the rad and the block. When I first got my car I drained the Rad and the Block 5 times I think, filling with distilled water each time, running for 10min in between. Basically until the drained coolant looked like water.

Yea this is what I'm going for, I'm also using vinegar. Not sure if that helps or not, I cannot believe the amount if rust.

So 5 flushes and it was clear?

[golde30]

damn, 5 flushes seems like alot. also you wasted that distilled water, just use tap water for flushing and distilled at the end when you refill the coolant.

This is why you run the real bmw coolant and distilled water in bmw engines. i let my s50 sit for 4 years, when i drained it out it looked brand new. The problem is people like to keep topping off their cooling system with tap water, and over the course of a few years that tap water rusts the shit outa the internals. I saw this ALL THE TIME when i was a mechanic.

[jlevie]

Here you go...


1) Get the front of the car 1-2' in the air on jack-stands.

2) Drain the coolant, remove the thermostat, and set the heater controls for
full hot. O-ring sealed thermostats require you to make up a temporary
gasket, which can be made out of pasteboard.

3) Add flush compound and fill with plain water. Then run the engine at normal
temperature as specified by the flush manufacturer (usually about 15
minutes at operating temperature). In cooler weather it may be necessary to
block off some of the air into the radiator to decrease the warmup time.

4) Allow the engine to cool until you can place your hand on the cylinder head
w/o discomfort. Drain the system and refill with plain water.

5) Run the engine for 10-15 minutes or until temp is close to normal.

6) Repeat (4) and (5) until the water drained from the system is clear and
free of debris.

7) Fill with coolant. It is best to dilute aiitfreeze with distilled water.
Tap water contains disolved oxygen and may contain minerals. Either of
which will reduce the lifetime of the coolant.

Notes:

You don't absolutely need to remove the thermostat, but doing so will allow
continuous flow through the radiator and will also make draining & filling
faster and easier.

Always allow the engine to cool to the point that you can hold your hand on
the cylinder head without discomfort. That will prevent scalds from hot
coolant and prevent thermally shocking the head when you dump the coolant.

Filling the system with hot water makes the process go faster and keeps from
having to run the engine a lot in a cold condition (rich mixture).

A few ounces of Cascade dishwashing detergent is a reasonable substitute for a
commercial flush compund.

A rusty cooling system needs an oxalic acid flush. Kits for that (containing
oxalic acid and soda for neutralizing the acid) used to be available, but
arent now. Citric acid also works, but not as well on rust as oxalic acid. 6oz
of oxalic acid and 4oz of soda will treat a 1-1/2 to 2-1/2 gallon cooling
system. The procedure is like the above with an extra step 4 where the soda is
added before the series of fill/drains are done. An engine that needs this
treatment probably has a pretty severly clogged/damaged radiator and heater
core, which stronly suggests that they be replaced after usin this procdure on
the cooling system. A cooling system that needs this treatment should have a
detergent flush, the acid flush, then another detergent flush. The initial
detergent flush will clean out any oil, which would interfer with the acid
flush, and the final detergent flush helps to wash out loosened sediment.

[IRON-E]

Here you go...


1) Get the front of the car 1-2' in the air on jack-stands.

2) Drain the coolant, remove the thermostat, and set the heater controls for
full hot. O-ring sealed thermostats require you to make up a temporary
gasket, which can be made out of pasteboard.

3) Add flush compound and fill with plain water. Then run the engine at normal
temperature as specified by the flush manufacturer (usually about 15
minutes at operating temperature). In cooler weather it may be necessary to
block off some of the air into the radiator to decrease the warmup time.

4) Allow the engine to cool until you can place your hand on the cylinder head
w/o discomfort. Drain the system and refill with plain water.

5) Run the engine for 10-15 minutes or until temp is close to normal.

6) Repeat (4) and (5) until the water drained from the system is clear and
free of debris.

7) Fill with coolant. It is best to dilute aiitfreeze with distilled water.
Tap water contains disolved oxygen and may contain minerals. Either of
which will reduce the lifetime of the coolant.

Notes:

You don't absolutely need to remove the thermostat, but doing so will allow
continuous flow through the radiator and will also make draining & filling
faster and easier.

Always allow the engine to cool to the point that you can hold your hand on
the cylinder head without discomfort. That will prevent scalds from hot
coolant and prevent thermally shocking the head when you dump the coolant.

Filling the system with hot water makes the process go faster and keeps from
having to run the engine a lot in a cold condition (rich mixture).

A few ounces of Cascade dishwashing detergent is a reasonable substitute for a
commercial flush compund.

A rusty cooling system needs an oxalic acid flush. Kits for that (containing
oxalic acid and soda for neutralizing the acid) used to be available, but
arent now. Citric acid also works, but not as well on rust as oxalic acid. 6oz
of oxalic acid and 4oz of soda will treat a 1-1/2 to 2-1/2 gallon cooling
system. The procedure is like the above with an extra step 4 where the soda is
added before the series of fill/drains are done. An engine that needs this
treatment probably has a pretty severly clogged/damaged radiator and heater
core, which stronly suggests that they be replaced after usin this procdure on
the cooling system. A cooling system that needs this treatment should have a
detergent flush, the acid flush, then another detergent flush. The initial
detergent flush will clean out any oil, which would interfer with the acid
flush, and the final detergent flush helps to wash out loosened sediment.

Holy Jeez, this man deserves an honorary medal or something, he is on point every time I read his replys.

I will save this for future referance.

[bastianshaw]

is it weird that im not getting coolant out of the bleeder screw?

[jlevie]

The passage in the tstat housing could be plugged.

[Eddie Haskell]

Oxalic Acid is avaliable at most good paint stores or HD. It's used for bleaching wood. A good Neutralizer is common Baking Soda. If your flushing a radiator with Oaclic Acid flush with tap water . Plug the radiator and pour in a half box (small box) of Bakeing Soda then pour in a Large Bottle of Coke and shake. Flush the mixture and you will be good to go.