draining coolant
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 6,366
Likes: 249
From: Fort Lauderdale, Florida
draining coolant
2003 Z06. I'm having trouble getting my radiator drain plug open. Can't decide on correct tool and which way to turn. I've done this before a long time ago and seem to remember there was some unusual about doing this. Shop manual is very vague about this.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
Here are notes I wrote last time I changed coolant.
Loosened the radiator draincock located on the lower right corner of the radiator. NOTE – the draincock is plastic, and only loosen 1/4 turn using a 1/4” square drive extension. Trying to loosen more than 1/4 turn can damage the draincock. I was able to open the draincock without jacking up the front end of the car.
Loosened the radiator draincock located on the lower right corner of the radiator. NOTE – the draincock is plastic, and only loosen 1/4 turn using a 1/4” square drive extension. Trying to loosen more than 1/4 turn can damage the draincock. I was able to open the draincock without jacking up the front end of the car.
Last edited by ZeeOSix; Jul 28, 2013 at 03:33 PM.
Le Mans Master
Joined: Sep 2004
Posts: 6,714
Likes: 6
From: Providence RI
I loosened the draincock 1/4 turn recently to change my coolant before I stripped the nylon plug. (only GM would come up with something this stupid). It wasn't close to coming out so I had to pop the stat to only get most of it out.
Team Owner
Joined: Sep 2001
Posts: 23,283
Likes: 905
From: Lake Elsinore, CA
Done tthis several times - use a 1/4" square drive ratchet extension and turn it 1/4 turn CCW to loosen it. Last time I did it was last December when I was replacing the water pump and crank pulley. I discovered it is O-ring sealed and will actually come out all the way if you pull on it after loosening it - not that you need to to drain the radiator. I was playing with it and it popped out when I tugged on it.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 6,366
Likes: 249
From: Fort Lauderdale, Florida
Done tthis several times - use a 1/4" square drive ratchet extension and turn it 1/4 turn CCW to loosen it. Last time I did it was last December when I was replacing the water pump and crank pulley. I discovered it is O-ring sealed and will actually come out all the way if you pull on it after loosening it - not that you need to to drain the radiator. I was playing with it and it popped out when I tugged on it.
Melting Slicks
Joined: Mar 2004
Posts: 2,384
Likes: 403
From: Horseshoe Bend ID
The OEM plug is a POS plastic part with a metal pin. Use the 1/4 square drive, turn it 1/4 CCW and pull it out. If you turn it any more than that, you will shear the pin off (trust me). NAPA sells a replacement piece with "a butterfly wing" instead of the square drive, much easier to use.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
There is no need to totally remove it. Just turn it 1/4 turn and the radiator will drain just fine without the draincock totally removed.
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Le Mans Master
Joined: Sep 2004
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From: Providence RI
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 6,366
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From: Fort Lauderdale, Florida
FYI, for anyone wanting to change the original drain plug to the type with a wingnut end instead of the socket (I screwed up the socket on mine because it was stuck in there) when you get it out in the drain position you have to tug on it because there is a o-ring holding it in. The new one just pushes in until the o-ring is free and then you turn 1/4 turn clockwise by hand to close. I bought a new one at Advance for $4.99 with the wingnut end. Problem fixed. Now to go fill and bleed my system.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
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From: PNW
Drifting
Joined: Jan 2008
Posts: 1,752
Likes: 62
From: New Madison Ohio
I don't mean to hi-jack the thread on this, but I may be replacing the t-stat in my 98. Do I need to drain the radiator completely or just a little like the good ole days? Thanks...and apologies to the op for this question.
Thread Starter
Le Mans Master
Joined: May 2005
Posts: 6,366
Likes: 249
From: Fort Lauderdale, Florida
Sorry, I couldn't find my receipt, but if you got to Advance it's just their GM replacement plug. The counterguy said they always have them in stock, retail is $4.99.
Melting Slicks
Joined: Sep 2012
Posts: 2,308
Likes: 159
From: LaGrange Park, IL IL
St. Jude Donor '13, '15
Is flushing the coolant really as simply as opening the drain **** to drain, close it back up and then fill up the radiator opening with new Dexcool?
It's been a long time since I had a car that had to have the coolant changed. Seem to remember my dad doing something with a hose to "flush" all the old out? It was a mess and seemed difficult...at least to a young teens eyes.
Dealership wants to charge me $150 to do the job. I'm an average DIYer, and have basic hand tools.
It's been a long time since I had a car that had to have the coolant changed. Seem to remember my dad doing something with a hose to "flush" all the old out? It was a mess and seemed difficult...at least to a young teens eyes.
Dealership wants to charge me $150 to do the job. I'm an average DIYer, and have basic hand tools.
Melting Slicks
Joined: Apr 2002
Posts: 2,631
Likes: 2
From: Clever, MO aka SOMO
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
Remove the reservoir tank pressure cap and small rubber hose on the tank that comes from the top right of the radiator before draining the radiator. Loosened the radiator draincock located on the lower right corner of the radiator. After the radiator has drained, blow air into the reservoir tank filler cap hole with your mouth to help force coolant from the system. Cover the nipple on the reservoir tank that the small hose was connected to while blowing into the tank.
I got a total of ~8-1/2 quarts out of the system doing it this way. The Owner’s Manual says the total cooling system capacity is 12.6 quarts. So this drain & fill method got about ~70% of the system replaced. Good enough if you're replacing the coolant every 4~5 years with Dex-Cool.
Last edited by ZeeOSix; Jul 30, 2013 at 04:54 PM.
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 794
From: Longview Texas
If you look at the radiator housing around the plug closely, you can see the slot that the metal pin must be lined up with for the plug to pull straight out. You can turn it past the slot, and the plug will continue to come out, but the pin will retain the plug in the radiator housing.
The pin is in a spiral track, so that it slowly comes out as you turn it.
I have always been a little afraid that the 1/4" drive would round out the hole, so I usually end up carefully grabbing the outside edge of the plug with a small pair of channel-locks and wiggling it back until the coolant starts to come out...
The pin is in a spiral track, so that it slowly comes out as you turn it.
I have always been a little afraid that the 1/4" drive would round out the hole, so I usually end up carefully grabbing the outside edge of the plug with a small pair of channel-locks and wiggling it back until the coolant starts to come out...