Flushing Radiator & Block HOW TO

Z()LTAN · #1 07-02-2006, 05:51 PM

When u do a radiator flush it isnt as simple as changin the fluid in the radiator as there is almost 1/3 of it in the block,

U need run the engine till the fan comes on (with the radiator cap off) then when the fan stops turning, take the bottom hose of the radiator and keep the engine running, the raidiator should flush and then block should also when the thurmostat opens, get it nice and hot but not too hot (just keep an eye on the temp guage) then put the bottom hose back on but dont tighten it.

Put the water hose in the top of the radiator and fill it up and reapeat again. Flushes the block well. Turn the car off and put all pipes back on and fill the radiator up.

Turn the car back on and open the thermostat again and continue to fill with ur coolant mix, keep it runnin for a few thermo cycles and continue to fill up the radiator

After this is done open the air bleeding screw at the top of the thermostat housing and bleed the top and air out and top up as nessesary.

Put the radiator cap back on and presurise it by goin for a quick drive.

Come home and let it cool down (wait about 1-2 hours) then open radiator again and top it up.

The radiator and block should now b fully flushed and blead!

sixshooter · #2 07-02-2006, 06:47 PM

Good way to make your radiator crack....shocking it with cold water out the hose after having it fully hot...

Who gave you that advice ?

Better to take the thermostat out and run the motor from cold with the hose stuck in the top radiator hose then pull the bottom hose off and repeat...

There's really no need to get the motor hot for a block flush...and dont forget to turn your heaters on also to clean them out aswell...

just my 2c worth...

Rocky1 · #3 08-02-2006, 09:44 PM

There is another, easier way. Remove the Knock sensor/s from the block & all the water will drain. Make sure the heater is on.

Shounak · #4 10-02-2006, 09:29 AM

Taking off the bottom hose, whilst the car is on? I agree that it's a good way to get rid of the coolant in the block but I'd never do it whilst the engine is running..

Unless you're simultaneously pumping water back in the waterpump, via the lower hose opening..

Even that's a bit dodgy I reckon..

Shounak · #5 10-02-2006, 09:35 AM

I just disconnect lower hose at radiator and top hose at the radiator.. Put a garden hose in the lower lose and let the water flush through the block until it's clean..

Put the garden hose in the bottom of the radiator and put your hand at the top the block off the other opening.. Then fill the radiator with water and then let it all drain.. Do it a few times..

Turn on heater to high and full blast. Connect all the hoses back up and fill the system with clean water and even a flush treatment if you want.. Run it through the car and drop the lower hose.. The water will be a little green..

Do it again, drop the lower hose and fill up with water, run it through the system and then drop the lower hose..

One step I left out is disconnecting the heater hoses, but I just run the heater on high and let the water flush all the coolant out of it..

Oh and you can disconnect the knock sensor wires to drain the block, if you so wish..

My method would probably take a bit longer then yours.. But I swear by it..

Don Sutton · #6 10-02-2006, 10:30 AM

Quote:

Originally Posted by Shounak

I just disconnect lower hose at radiator and top hose at the radiator.. Put a garden hose in the lower lose and let the water flush through the block until it's clean..

You forgot to remove the thermostat first as it will close and no water will flow through the block.
When I served my apprenticeship as a mechanic, we had a kit with a large tappered bung with a garden hose attachment. The thermostat housing was removed from the block and the bung placed into the opening in the block. The hose was connected and the water turned on reverse flushing the engine and radiator. This was done engine cold.

Cane_It · #7 12-02-2006, 10:16 PM

Quote:

Originally Posted by sixshooter

Good way to make your radiator crack....shocking it with cold water out the hose after having it fully hot...

Who gave you that advice ?

Better to take the thermostat out and run the motor from cold with the hose stuck in the top radiator hose then pull the bottom hose off and repeat...

There's really no need to get the motor hot for a block flush...and dont forget to turn your heaters on also to clean them out aswell...

just my 2c worth...

who cares about cracking the radiator!! what about the block and the heads?!?!

sixshooter · #8 14-02-2006, 01:36 AM

Quote:

Originally Posted by Cane_It

who cares about cracking the radiator!! what about the block and the heads?!?!

Less likely due to the thickness of the block and being cast iron...

but I wouldn't risk it...

getting your motor hot and then filling up with cold water won't do it any good thats for sure....:b:

kopper69 · #9 15-02-2006, 09:17 AM

I think this how-to guide nears to be deleted and a new one written up. Too many conflicting instructions. It wouldnt be any help to a new member trying to follow - Do this - No dont do what he said.

killuminati · #10 15-02-2006, 01:24 PM

Yeh, i wouldnt mind knowing how to do it the best way, even if it takes a lot longer.

HDT_aero · #11 15-02-2006, 03:11 PM

you get the high pressure sprayer with the tiny always on connection and snake it through the block whilst on and with the detergant pickup in a bottle of hyperclor

that should do the trick

just kidding if anyone thinks im serious

CommyLover · #12 06-02-2007, 02:58 PM

did a redo of this thread ever get completed? im really interested in the best way of doing this

Lloyd1986 · #13 08-02-2007, 01:43 AM

Get a Gergorys or Haynes manual, tells you how to do it. DEFINATLY dont do it while the engine is hot or warm though. Radiator flush should be done with a cold engine. To drain the sump just take the knock sensor out, its not hard.