Steam Vent...Thoughts on where to plumb it?
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On The Tree
Joined: Nov 2011
Posts: 159
Likes: 0
From: South east Wisconsin
Steam Vent...Thoughts on where to plumb it? So I decided to plumb my steam vent into the water pump. Casey Wegner (built my engine), recommended that instead of tapping into the pressure side of the water pump, tap into the suction side of the water pump. So thats what we did. Since doing this mod I have received mixed feedback from others about this mod. So I am looking for more feedback good or bad. 
I may be way off here but I would think the steam vent should be above the steam ports. The cooling system is under pressure as soon as it get hot, I'm not seeing any trapped air being able to escape. I have mine going into my upper radiator hose, which it then can keep traveling up to the top of the rad, letting any air travel naturally up to escape.
Lots of guys just cap those things off without any trouble. I mean a lot of guys. Once you bleed the air on initial fill they aren't really needed anymore. Putting in a vent line just protects you in case someone fills the system without venting it properly.
Since you have it plumbed to the suction side of the WP it should draw a pretty good flow through the line. That should evacuate the air pretty effectively. If you are really worried about it then see if you can temporarily put in some type of clear tube and check for coolant flow with the motor running. if you get flow then you are golden.
Gorgeous motor by the way.
Since you have it plumbed to the suction side of the WP it should draw a pretty good flow through the line. That should evacuate the air pretty effectively. If you are really worried about it then see if you can temporarily put in some type of clear tube and check for coolant flow with the motor running. if you get flow then you are golden.
Gorgeous motor by the way.
Steam Pocket Venting Many older engines, especially British ones, had captured high spots in the cooling passages that were prone to steam pockets. This issue either required special filling proceedures or pepcocks installed to allow manual venting. While I am sure that in the case of the LS motors, proper filling alleviates any steam pocket formation. I would rather play it safe and vent these pockets. As for pressure or suction side. I would think the suction side would be preferable. The entire engine cooling system is under pressure and it would be very difficult to know the exact pressure at the steam pocket locations. If the pressure from the vent line is less then or near the existing system pressure it may cause stagnent flow or turbulence possibly leading to overheating the coolant. If on the suction side then the vent line pressure is almost guaranteed to be lower then existing system pressure. But really, this is probably all spliting hairs. If people get away without venting the steam pockets, you can be pretty sure that you will be fine. Just my $.02.
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Launching!
Joined: May 2012
Posts: 205
Likes: 2
From: Mobile, Alabama
It will probably be fine where it is. The Trailblazer SS vent went to the heater hose return to the pump. The only reason I wouldn't do it this way, is because you would have to modify a pump, pain on a road trip, if this one went out. I am sure some will get away with no vent, but Chevy engineered it for a reason. Continuously removing air from the system makes it more efficient. Look at how later model cars, not just Chevy use surge tanks to vent and de-aerate their coolant. I am using a Mercedes surge tank plumbed to the heater hose, and it has a steam vent inlet as well.
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Verdad Gallardo I would run it. After you get it running and the cooling system pressurized, crack one of those fittings on the steam vents and see if any air escapes before you get coolant. If you only get coolant and no air I would call it good!
https://ls1tech.com/forums/forced-in...4-why-7-a.html
TECH Fanatic
Joined: Oct 2011
Posts: 1,356
Likes: 2
From: Felton Pa
I did away with the steam tubes all together. The 03 truckengine that I am using only came with a steam tube that ran between the front 2 ports. The rear ones were blocked off factory. I left the caps off the head when I filled the coolant system and when I saw coolant start to dribble out I put the caps on. Been in the car without steam tubes since May and have put about 2000 miles on the engine and have hadzero temp issues. As for #7, I can't see it getting any hotter than in a factory applicaion. If mine gives out I will allow people to say "I told you so!"
I'm going to respectfully disagree with you. I like all of my cylinders.
https://ls1tech.com/forums/forced-in...4-why-7-a.html
https://ls1tech.com/forums/forced-in...4-why-7-a.html
If you honestly think you have "steam vapors" in your heads then by all means, drill a few more holes and add vents everywhere you can get them. But please, don't do it just become some guy on the internet tied two, quite possibly unrelated issues together.
What I said was factual, there are a LOT of guys who block all 4 vents with absolutely zero problems. All I do is throw that out and let people decide for themselves.
Launching!
Joined: May 2012
Posts: 205
Likes: 2
From: Mobile, Alabama
You know I have spent enough time on the internet to know that people make things up then post them as fact. I find it difficult to sift through some of that stuff without coming off as a flaming ***. It took me about 6 months of challenging people's ideas about "steam vents" to finally get an answer of why some people can run with them blocked that made sense. Thank you John Mc Graw.
If you honestly think you have "steam vapors" in your heads then by all means, drill a few more holes and add vents everywhere you can get them. But please, don't do it just become some guy on the internet tied two, quite possibly unrelated issues together.
What I said was factual, there are a LOT of guys who block all 4 vents with absolutely zero problems. All I do is throw that out and let people decide for themselves.
If you honestly think you have "steam vapors" in your heads then by all means, drill a few more holes and add vents everywhere you can get them. But please, don't do it just become some guy on the internet tied two, quite possibly unrelated issues together.
What I said was factual, there are a LOT of guys who block all 4 vents with absolutely zero problems. All I do is throw that out and let people decide for themselves.
Here is a fact and not some internet opinion or myth. GM installed and hooked up the steam vents. They could have saved millions of dollars by not installing steam vents. Why did they hook up the steam vents?
I had to replace my water pump on my lq4 block. For ***** and giggles I started it without the steam tube hooked up to my pump because I hadent tapped the pump yet. After the engine got warmed up it was actually blowing a light mist of steam out of the hose. Also im running straight water in my system if that changes it Idk.
TECH Fanatic
Joined: Oct 2011
Posts: 1,356
Likes: 2
From: Felton Pa
I had to replace my water pump on my lq4 block. For ***** and giggles I started it without the steam tube hooked up to my pump because I hadent tapped the pump yet. After the engine got warmed up it was actually blowing a light mist of steam out of the hose. Also im running straight water in my system if that changes it Idk.
Launching!
Joined: May 2012
Posts: 205
Likes: 2
From: Mobile, Alabama
Not sure if you know but the actual increase in pressure in the system raises the boiling point of water. So when the system is open(no cap or open line) the water will boil at 212*F, or more depending on your antifreeze mixture. When you seal the system and it builds pressure you raise the boiling point depending on your antifreeze mixture to well above that. So it would be normal to see steam there if the line is disconnected. It would be abnormal for a properly sealed and mixed coolant system to build steam. Unless of course there are other problems with the car/engine.
Last edited by 74modified; Sep 8, 2012 at 05:26 PM.