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Draining the Coolant

Joined
Aug 29, 2001
Messages
3,222
Location
Norcross, Georgia, United Stat
Corvette
2017 Arctic White Grand Sport
Trying to flush the colling system and am in the process of trying to drain the block. The books say there are drain valves on either side of the block near the oil pan rail about 1/2 way back. I've been under there and don't see anything that looks like such an animal. Can someone give me a better description?

Also, I want to back flush the system. Do they still make those kits for the heater hose that you hook to a garden hose and should they be used?

Bob
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Its a plug

Not a valve, I would use caution here.. had a buddy who would not give up till he got it out.

He used a BIG BUTT breaker bar and sheared the head off the plug ( brass fitting) which left a nice 3/8 drain hole in the bottom of his block.

Then 4 hours later he finally got it sealed back off by tapping the cruddy remains of the plug frozen in the block.

Prestone still makes the flush & fill kit ( which I use) yellow T that goes to the heater core line, garden hose etc.

Danger here....

If the coolant system has REALLY OLD STUFF IN IT.. there is a chance that the heater core will let go or a freeze plug or a water pump seal.

I would flush.. but do not be surprised when a week later you have a green puddle under the car.

Rust bits make good sealer.

Mike
 
Joined
Aug 29, 2001
Messages
3,222
Location
Norcross, Georgia, United Stat
Corvette
2017 Arctic White Grand Sport
Mike,

Doesn't appear to be too rusty. Maybe I won't back flush but will just put in new coolant.

If you don't want to take off the drain plug, how do you drain the block? Will removing the lower radiator hose do it?

Bob
 
Joined
Nov 4, 2000
Messages
947
Location
Scottsville, Kentucky
Corvette
08 Jetstream Blue Z51 coupe
Bob

If you want to try to remove the block plug/s use a good penatrent before you get the wrenches out. Kroil or PB Blaster work very well and one or the other should be available to you. Then play it by ear, if you feel the need to get a larger longer tool to remove the plug then it may be time to use plan "B". Plan "B" for me, is to follow the instructions on any good radiator flush product such as Prestone or Xerex and then install new coolant.
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
6 O one

Just bleed the radiator ( park the car on a slight nose down position)

You will be FAR better to do more coolant flushes then to snap a plug.

Inspect the freeze plugs..poke em gently..if they go, well better in your driveway then on the road.. but if there all fine..then it will be safer to power flush..if you feel the need.

The garden hose does 14 psi ( at least here)

Your cooling system takes more than that on a daily basis.

Mike
 

Stingray6974

Well-known member
Joined
Oct 12, 2000
Messages
494
Location
Garland,Texas
Bob,
Take out the thermostat, stick the garden hose in the radiaitor and turn it on. When clean water comes out of the intake turn off the hose. Pour anti-freeze into the radiator until it starts coming out the intake. 2 gallons max. Install new thermostat and gasket, top off the radiator and start it up. If you want to back-flush it, after you flushed with the hose in the rad, put the hose into the intake until clean water comes out the radiator. You don't have to drain anything or get under the car.
Mike
 
Joined
Aug 29, 2001
Messages
3,222
Location
Norcross, Georgia, United Stat
Corvette
2017 Arctic White Grand Sport
I elected to add the backflush valve in the heater house coming off the intake (hope this is the right one). Back flushed until clear water come out of the radiator and then added coolant until it came out the backflush valve. Ran the car and tomorrow I wil check and see if my freeze protection is okay.

Thanks for everyones help.

Bob
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Cool

You did run it in the driveway for a while right?

Mike
 

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