[Topspin]

Hi
I am wanting to do a coolant flush on my 5.3 and want to know if they are drain points in the engine block ?
How many and where they are located.

I have an issue with the original Dexcool being mixed with normal coolant and they did not mix well. Sort of sticky gunk now visible in the expansion tank.
Thanks for advice
Richard

I can offer some help. The 2nd photo is the driver side of the block. The large brass plug at the front is a water jacket drain - takes a 17.5 MM Allen wrench.

The first photo is the pass. side, though the block is upside down - Sorry, only shot I had handy. You can see the plug at the rear of the block - it takes an 8 MM allen wrench. It's facing up in the photo, but is facing down in the truck.

 

[Topspin]

Are they low enough to drain the block of water or do they still leave water in the bottom of the block? I thought I read someplace they are not like the old small and big blocks with drains in the lower part of the block that allowed you to get most of the water out. On the LS blocks it left quite a bit of water in the block still? I don't know and was going by what I had read on the ole innerwebs and we all know how accurate that is.

Pass. side will drain 90%, while the driver side will yield around 75%.

 

[Topspin]

Driver side seems to be lower .... any comment? I just want to open one. Thanks

If your intention is to drain most of the coolant, opening only one plug won't do it. The two banks of water jackets are not connected. Also, I believe you may be looking at the wrong plug on the driver's side. It's the large brass plug on the front of the block. There is a steel plug, at the rear, that is an oil passage plug - don't confuse that as a coolant plug. Good luck!

 

[Topspin]

Thanks a lot or answering. In this picture you are saing this is the wrong plug?
View attachment 653335

That is absolutely the wrong plug. That's the oil pan drain plug on a C6 oil pan that I was mocking up. The large brass plug, above and slightly left of the oil filter, is the drain plug for that side of the engine. And don't expect your engine and filter to look like that as the filter and lines are aftermarket parts.

Also, if you want to change the text of a previous post, you can do so. In the upper right corner of the post there are three vertical dots. If you click on those you'll find a "edit" function. Click on it and you can go back and change anything in your post.