How do you drain coolant from a LS1 block?

[curt96ws6]

I'm changing the coolant in my 99TA and I would like to drain all of the coolant from the block. What is the best way to do this. I know on the LT1's, you just remove the knock sensor and it will drain the block. I'm not quite sure how to drain the LS1 block. Can anyone help me out. Thanks, Curt

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[SFB767]

Put your car on ramps and if you look under the right side of it towards the front, before the air dam, you'll see a small black wingnut. Turn that and your coolant will drain.

[curt96ws6]

Yes, that black wing nut will drain the radiator and some of the coolant in the engine. What I want to do is drain all of the coolant from the engine. I just want to know if there is a plug somewhere on the engine block that I can remove and all of the coolant will drain from the block. Thanks for your response though.

Thanks,
Curt

[DS01Z28]

Curt,
I just had my '01 Z28 power-flushed at a shop(30k miles on it). I watched like a hawk and the guy said that since the radiators are installed at an angle, they have to be "burped" to reinstall the radiator fluid. It's a bit tedious, but it needs to be done.

To do a "power-flush" as a home job (vs. having a shop do it), try draining the fluid per usual then run it through with water until it drains clear. That'd by my only suggestion short of having a shop with a power-flush machine do it ($40 + you supply the fluid).

Daryl

[curt96ws6]

Daryl,
Thanks for your response. I thought about just flushing all the old antifreeze out with a garden hose. The only problem with that, is that I wanted to mix my coolant with distilled water. They say distilled water is much better than water from your tap.

Thanks,
Curt

[DS01Z28]

Yes, I've heard the same about distilled water vs. tap water. I use distilled on my cars that I can do the complete flush on, but I wonder what kind of water the shops use when they do the flush for me? (I forgot to ask during the power flush on my Z28).

Make sure you use DexCool fluid, of course. Maybe you could have a shop power flush it for you then provide them with the DexCool and the distilled water (1 gal of each)???

Wish there was a slam-bang answer for this, but you may have to resort to the above plan...

Daryl

[9C1/B4C]

Curt,
Looks like you never got an answer to your question.
There is a block drain plug at the driver's side front of the block, right behind the alternator. A brass plug with a large indented hex. Anyone ever opened this? I think that is what drains the LS1 block, but I am looking for something to fit in the hex. There doesn't even seem to be a Kent Moore tool for that hex. It is in a gosh awful place to get at, even with the car on a hoist.
Terry

[9C1/B4C]

On a Corvette forum a post stated that it is a 17mm hex. I'm still looking for either a tool or a short length of 17mm hex stock.
Terry

[curt96ws6]

Thanks Terry, Let me know how it works out.

Thanks,
Curt

[9C1/B4C]

I did confirm that it will take a 17 mm hex to get that brass plug out -- I found a metric bolt with that size hex head. I am reluctant to cobble together something, and am looking for a piece of 17 mm hex stock, or a proper socket with that size hex. I just don’t want to do more harm than good.

There is a smaller plug on the passenger side, with a more modest size hex hole in it, but it is above the starter, and looks like the starter would have to be removed, or at least moved some, to get at it.

I'm still working on it, and will let you know if/when something happens.

I wish I could find someone who can assure me that the plug on the driver’s side will drain the cylinder case.
Terry

[9C1/B4C]

Well 17mm hex driver from Snap-on did the deed. Took about one foot of extensions and a universal joint to get the hex out.

http://www.ls2.com/boggs/torques/drainfillcoolingV8.htm

The link contains additional links to two drawings of the LS1 block drain plugs

Terry