flushing the engine block

[EA8]

It would be best to be a bit more aggressive in cleaning the cooling system. There are commercial flush compounds that will do a good job of cleaning the system. The procedure I use is:

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

2) Drain the coolant and remove the thermostat. Set the heater controls for
full hot.

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.

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) Re-install the thermostat and fill with coolant.

Notes:

You need the thermostat out in order to have full flow through the radiator.
That 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).

just got done flushing my entire coolant system ... replaced the thermostat (75 for an 80) and all is well. Heat is better than before and I didn't hurt myself. Now a quick question (most likely a dumb one), how in the world can you flush the engine without spraying coolant all over the place? I had to put my hands right in front of the the drain to guide it into a bucket :D.

jlevie, thanks for the info, great stuff ... Cheers

[xLibelle]

thats pretty much what you have to do.
edit: had to drain the block yesterday - i had an old coolant hose laying around, it had a 90 degree angle at the end. Put the bucket under, get the hose ready, spin the bolt out, small splash, cover hole and no mess.

this thread should be relocated to the DIY forum.

[Adrian_Visser]

Be careful not to fuck shit up by flushing ice cold water into your hot heater core, grr i just flushed my system out and tee-d in my garden hose into a heater hose, flushed it out good i dunno if it was the high water pressure or cold water but i was getting impatient this being the fourth flush cycle and it getting dark. Anyways you can crack your rad OR your heater core by shocking them with cold water.