dumb newbie question on the 5.3 engine

[oldman3]

I'm just getting started on checking the 5.3 engines, would like to know as much as I can. I have read several of the LSx swap thread on the site. I have learned a lot so far. I keep hearing about the steam line. So what is the steam line, where is it at on the engine? I am guessing it returns to the cooling system some how? Thanks for any help...Jim

[bohmankid]

You'll see the lines coming off the heads. The line goes into the throttle body, and back out into the radiator. Most people who do this swap bypass the throttle body, and go directly into the radiator, or radiator hose or water pump. Here are some pictures for people who would like to learn visually. The only rule to follow when doing your steam line is to keep it as high as possible. Others will chime in who know more than me.

Here you see the line going into the throttle body. Not necessary.


Some ppl will tap a line into their water pump or neck (used mostly by guys who want a 'clean' swap with as little wires and hoses as possible.


Here is a picture going directly into the upper radiator hose. (This is what I'm doing)


another one.

[homemade87]

The way these ls motors are built they will hold air pockets in them. The way to get rid of the air pockets is to create a passage to the rest of the cooling system. From the factory there is a small hose that comes from the front of the motor to the radiator. On these swaps you can do a couple of things, add a fitting to the radiator , put it inline on the upper hose , or drill and tap the top of the water pump and add a brass fitting. Most any way will work as long as you get tied back into the cooling system.

[oldman3]

Thanks guys for the great views,the breakdown of how it works, and the different ways to return to system....Jim