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I have completed the installation of an LS1 from a 2000 Camaro into my 57 chevy. I am having some odd issues with heating that don't really make sense.
It seems that I am having trouble getting the engine to "burp" all of the air out.
My question today is: If I take the hose loose from the steam line near the throttle body inlet, should this have a full flow of coolant out? Mine has a has a very small flow, which will pick up some if I rev the engine up, otherwise the flow is near none.
This makes me wonder if I may have a plug somewhere in the steam line system.
Will I damage anything to blow back with an air hose? Should it have a full flow out if the engine is running?
I am new to the LS engines and don't want to do anything to damage anything.
That is just what the name implies...vent. It is not designed to have a lot of flow. It's designed to avoid said air/steam pockets. Most route this into the radiator or expansion/overflow tank as the throttle body connection is suboptimal for performance. Do you have two or four (head)corners hooked up? When you say you are having odd issues with heating, do you mean your heater, or cooling issues with the motor?
Cooling issues. The car will do fine on highway, but will heat up and do some internal gurgling when you get into town or just idle at the shop. if the radiator cap is off it will puke coolant out. at highway speeds it runs 190ish . does this with heater on or off. Acts to me like still has some air trapped somewhere. Griffin aluminum radiator, stock type downflow with dual electric fans. steam line plumbed into top of water pump with throttle body heater bypassed.
Have you tried idling it up a little to see if you might need more flow at idle? How's your electrical system? Fans getting enough juice at idle? Have you tested you thermostat? Do you have your heater core lines hooked up and proper orientation?
I am going to change the thermostat, although the current one is new. the hose between the lower radiator and the engine inlet will be pretty much cool when the engine is gurgling. this says to me either trapped air or bad thermostat.
I just wish that there was a definite way to bleed the air. Everyone has their own way it seems. I think that I will get a pressure pump and pressurize the system (after changing to a new thermostat) and then remove the steam line and see if maybe that will push the air out thru the steam line.
One hot hose and one cold hose, I agree you've got a flow issue. Thermostat or water pump or a blockage. I have heard that if you don't have proper heater hoses or a loop back connected that the water pump may not function correctly at certain RPMs.
The steam vents are *supposedly* the answer to bleeding since they are about the highest cooling system location on the engine itself.
New water pump and it seems to make no difference if the heater is on or not.
I am now concentrating
on bleeding the air. That leads me back to the original question on this post about if the bleeder tubes could be plugged. I think I will blow them backwards into engine to be sure that they are clear. I don't have any indication that there is any reason not to put air pressure to them.
Well you could over-pressurize the cooling system which could be a negative. If you are going to change the thermostat, I'd wait until then to do it. I wouldn't expect major flow out of those though; they are vents. If you take off the intake manifold, the steam pipe comes off with either two or 4 bolts very easily depending on your setup. Which head corners are connected to the steam piping and what is the tilt of your engine if any when the car is sitting level?
BTW, the corners of the steam piping are held on with ~10mm bolt and sealed with these:
The steam tubes that I have are whatever were standard on a 2000 Z28 5.7. I don't know, but I suppose that they are tied to all 4 corners. Do you know if there are any check valves or other restrictions, or are they just open tubes?
To pressurize the system I plan to use the hand pumps that are used to pressurize the cooling system by putting on the radiator in place of the radiator cap. I can't believe that they pose any threat to the system.
I checked the steam tube setup from my LM7(2002-ish 5.3) and blew in one end and it was unrestricted out of all four corners. This was off the engine. Here's a pic of mine if you want to see what you might be dealing with(looking at underside):
4 corner factory LM7 LS Steam Pipe Setup Underside
Mercier, Thanks, That is exactly what I was needing to know. I hope to be able to get out tomorrow evening and getting it put back together. I hope that by filling with the steam tubes open ended that the air will escape. I will post when I get results. Thanks
Yep. Np. In my research, I've found that some engines only have two hooked up and can have issues with air/steam pockets if the motor isn't level in the car that it is installed in. I am unfamiliar with what the 2000 LS1 came with though.
I seem to have my heating issues fixed. I replaced the thermostat with a 2 piece unit and put an air bleeder hole in the thermostat housing to purge all air trapped between the lower radiator out let and the top side of the thermostat.
While filling the rest of the system I unhooked the steam line and was able to get full flow water out of each side before I hooked it back up and completed the fill.
Not for sure if I had just air, just bad thermostat, or combination of both, but so far, so good!!
I have found that idle timing affects my temps quite a bit. Do you know what it is? Perhaps try backing it down a few degrees and seeing if there's an effect?
For example, I'm running a Holley Terminator X, and I see many people on the forum/facebook group talking about running around 15 or more degrees at idle, and I'm running 12. Mine idles fine, but I tried bumping it up a few degrees, didn't change how it ran, but temps climbed quite fast at idle, so I put it back. Every engine combo is different.
I usually figure these two rules of thumb:
If it can drive down the road with fans off and sit at/about thermostat temp, then the radiator system is enough capacity
If it can cool at fully stopped vehicle, then it has enough fan capacity
When the fans are on, do you feel good airflow through the radiator? Like will it suck a piece of paper to the front of the radiator?
If all those things check out, (and it sounds like your fans are OK), I'd look at the timing.
My swap, a 71 GMC, I have nothing fancy. Autozone stock replacement for a 3/4 ton truck with HD cooling (aluminum, 2 rows, plastic end tanks), and a Ford Windstar (dorman replacement) e-fan. With a stock 187 degree t-stat, it sits at 190 solidly at any speed, and will bounce between 195-205 (my fan off/on settings) at a stop. 6.0, heads, cam, headers, etc.
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Question about steam lines 
