Engine Block Drain

[limeliam]

Hello, (2002 TJ), i am flushing out my jeep and was wanting to put in a new kind of coolant, do i have to drain the engine block or will just going through radiator will be fine? If I have to do the engine block was size bit? Thanks

 

[SSTJ]

You can drain the block but you don't have to. As long as you flush the radiator enough (times), all the fluid will be flushed.

For what they're worth, my notes are here. But they're specific to the 2.5L.

 

[jonny jeep]

When I changed to G-05 in my 97 4.0L I removed the drain plug from the block. There's quite a lot of fluid in there. I actually remove it every time I've changed coolant since then. I figure it's less time spent flushing the old coolant out and it really only the heater core that I need to flush.

 

[MountaineerTom]

I don’t know if they are all the same, but the OEM plug on my 2006 is an 8 mm square drive.

 

[jonny jeep]

I forgot to add the 8mm square drive size.

 

[lBasket]

I don’t know if they are all the same, but the OEM plug on my 2006 is an 8 mm square drive.

Wheres it at? I want to do a flush this year and see if any gunk comes out of the block

 

[jonny jeep]

Don't have a photo but this might help.

 

[lBasket]

Don't have a photo but this might help.

View attachment 596677

Oh nice thanks. That looks terrible to get to

 

[jonny jeep]

It'll be harder on a LHD. I don't have the steering shaft in the way on my RHD, so I'm not sure how much room you'll have to access it.

 

[MountaineerTom]

I ended up taking a couple pics when I did mine the first time. This is the 4.0. With the 8mm square plug adapter and extensions it wasn’t too bad. I put a light coat of Permatex Thread Sealant on the plug before I put it in for good.

 

[lBasket]

I ended up taking a couple pics when I did mine the first time. This is the 4.0. With the 8mm square plug adapter and extensions it wasn’t too bad. I put a light coat of Permatex Thread Sealant on the plug before I put it in for good.

View attachment 596678View attachment 596679View attachment 596680

So it's like a hex head bolt kinda thing but a nut? Or is it like the diff cover where the ratchet just goes into it? I was thinking the nut but that kinda looks like a hole

 

[jonny jeep]

It's a square socket. Like a ratchet but 8mm, which is between 1/4" (6.35mm) and 1/2" (12.7mm).

 

[lBasket]

It's a square socket. Like a ratchet but 8mm, which is between 1/4" (6.35mm) and 1/2" (12.7mm).

I see thanks! Course it's gotta be some weird special tool I'll never use again

 

[JKP]

It's a 5/16 pipe plug like the 3/8 diff plugs. 8 mm will work also.

 

[06lj]

This is the tool I used when I drained my block. If you have any rust I would just skip it and just flush then engine through the radiator. It would be a bad day if the plug stripped. Even on my rust free Jeep I almost gave up trying to remove it. I had the correct tool and even removed the fender so I had a straight shot at it.
https://www.amazon.com/dp/B00FRLBF4M?tag=wranglerorg-20

 

[MountaineerTom]

This is the tool I used when I drained my block. If you have any rust I would just skip it and just flush then engine through the radiator. It would be a bad day if the plug stripped. Even on my rust free Jeep I almost gave up trying to remove it. I had the correct tool and even removed the fender so I had a straight shot at it.
https://www.amazon.com/dp/B00FRLBF4M?tag=wranglerorg-20

I think that’s the same one I ordered and used as well.

 

[Danarch]

I used 8mm worked great. Came out pretty easy too. I was surprised at the amount of coolant that was in there.

 

[DuckNut]

If you are using a garden hose to do any flushing you will be way ahead to remove it. You don't want any city water in your cooling system as that is what breaks down the coolant and causes rust that plugs up the heater core and radiator. You only want distilled water in your system and without draining the block you only get 2/3 of the old fluid out.

But then again, it is up to you to make your decision.