HRDWRK

Hello All:
I need a clarification about these steam vent connections. I understand that LS engines seem to create steam but Why do they have to be connected to throttle body? Or do they have to? Doesn't antifreeze evaporate affect the engine performance? Can't you connect the steam vents to coolant recovery tank or even to coolant recovery tank over flow hose? IF LS engines create so much steam, I assume these engines lose coolant regularly, is this a correct assumption?And at the end, isn't the cooling system in LS engine pressurized?

bammax

The steam vents run through the throttle body to prevent ice if you drive in Alaska in January. You can completely bypass the throttle body and run the line directly to the radiator if you want.

The system shouldn't lose much coolant if it's working properly. Over time you can get some evaporation from the overflow tube of the overflow tank, but it's not going to be noticeable at all.

HRDWRK

Thanks for explanation. I am just trying to understand this. There is already one line from radiator going to (or coming from?) to throttle body, and then, there is another one from vent line from the heads, two separate lines to throttle body. Do you mean I can just connect the one line from the heads to the one from the radiator and bypass throttle body all together?

bammax

You have it figured out.

The steam line comes from the heads and allows any air trapped in the heads to escape as a way to prevent hot spots. The line then runs into the throttle body to prevent ice. From the throttle body another line takes the steam and runs it back to the radiator. If you don't need to heat the throttle body you can take the 2 lines off the throttle body and use an adapter to connect them together. That's the "throttle body bypass" if you need to look at details.

GM doesn't know what you plan to do with the car so they design for the worst case scenario. For most people throttle body icing isn't a real concern so the bypass was invented.
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8.Lug

B52bombardier1

It doesn't have to be Alaska in January to encounter carb / intake icing. The right set of humidity and temperature circumstances can do it elsewhere. This is why reciprocating engine airplanes run carb heat in the airport traffic pattern year round prior to landing.

Rick

HRDWRK

Please correct me if I am wrong, I think this is where I got confused: I know steam and air are two different things. I am assuming that lower section of the throttle body that steam vents connect to doesn't have any opening to the throttle body air passage. I thought steams vent in to the throttle body and it mixed with incoming air and burns in combustion chamber, That was why I was wondering why these engines don't lose too much coolants since as the engine gets hot some of the coolant can transform to steam.This would make total sense if it is just a recirculating passage with no connection to main throttle body and the engine breathing air flow.

8.Lug