Air/steam coming out of bleeder screw?

[bstarr3]

So I'm bleeding my radiator after doing mess under intake. Following this method :http://www.esatclear.ie/~bpurcell/31...nce.html#bleed

I filled both the expansion tank and the top radiator hose to jump start things. Hot air coming out of the heater, check. Top and bottom radiator hoses hot, check. Nothing really bleeds out of the screw until I rev it. But then I get lots of bubbly coolant. I kept it revved to about 3500 and was getting a steady stream of frothy bubbly coolant, then just steam. Now, I don't remember steam coming out of the bleeder screw as part of the procedure, and the temp gauge is close to red, so I turned it off. I turned it back on to take a quick video of my valvetrain tick (see next thread) and it started leaking steam straight away. Is this just lots of air getting out, or is something wrong here?

At any rate, I'm running out to let it cool off and do some errands, so I'll try again when I get back. BTW, front end is up on jack stands.

[bats]

Steam was normal for me, but it was very low in the expansion tank. Make sure it's kept up to level.

[bstarr3]

Update: felt like I was getting pretty close so I took it down to the store to warm it up (10 minutes round trip). By the time I got home, temp was approaching 3/4. I opened up the bleeder and got lots off steam but no fluid. I'll wait for it to cool down and check the expansion tank. It should be only to the 'kalt' line, right?

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[Massimo]

I keep the expansion tank topped up to the brim while bleeding. Then once done. I screw the cap down and wait for the car to cool down. Then once cool I bleed the coolant till the coolant level is on the Kalt line.

Don't let the expansion tank go dry otherwise you will just be bleeding air.

[Chuck C]

The only time the bleed screw should be opened is on initial filling of the cooling system. When no more bubbles come out of the bleed screw, the radiator is full. Tighten the bleed screw gently--the seal is made by the o-ring, not your manliness on the screwdriver. And don't put a fucking metal bleed screw in.

[immajackuup]

why not metal??

[bstarr3]

I continue this ongoing process of driving it around, bleeding it, then topping the expansion tank off. After reading the above post, I went to filling it about 3 inches past the cold line. I'll drive it around and it'll do fine (it's hot here today) but gradually creep up between just a needle's width past half and all the way up to almost 3/4. Hasn't gone past that point, though. Whenever I stop, I open up the bleeder screw and get some coolant/bubbles and some steam.

I thought I had it earlier today, because I had it parked on a nice incline and I got a few seconds of bubbles followed by a nice gentle gush of fluid with no more bubbles. Tightened it back up, filled to the cold line, and then ten minutes later while I was driving it was running hot again. Opened it back up (not on an incline this time) and got bubbles and steam. Then just steam. Expansion tank was nearly dry. Filled it up to 3/4 full. I can see why this radiator has such a reputation for being a PITA to bleed.

Best part is, I get to take the whole thing apart again this weekend to finish my timing chain job!

[Chuck C]

Are you getting the little stream of coolant, from the overflow, into the neck of the expansion tank when the engine is running? What happens to the heater output when the temp gauge starts going up?

[immajackuup]

i used to have this problem turn out to be a hair line crack where the bleeder screw into.

[Massimo]

Sounds like your water pump is shot or you have a blown hg.

[immajackuup]

pressure test your coolant system.

[gearheadE30]

Do the pressure test, and there is a test that can be run to check for exhaust gases in the cooling system. Most shops can do it, or you can buy the kit via Harbor Freight, I believe.

Part of this could just be that you're letting the cooling system heat up too much before you bleed it. What happens is when everything gets hot, the cooling system ends up being under pressure. I'm not quite sure how much exactly, but I think it's in the neighborhood of 10 psi. This pressure raises the boiling point of the coolant, so if it's already running hot and then you let some of the pressure out, you will pretty much get instant boiling in the head. This causes rapid expansion, and because steam is much, much hotter than hot coolant before it starts to boil, you get something of a chain reaction, which will leave you with lots of boiling and no more coolant. When I was fighting the issue, as soon as I saw it start to boil like crazy, I just tightened everything down and let it cool off so I didn't lose all of my coolant.

So short version: park on a hill, front of the car higher than the rear. The steeper the better, really. Open the bleed screw, put the key in the run position, and turn the heater on. Slowly fill the system with coolant/water, and keep filling until it gets to the top of the expansion tank. The top of the tank is actually above the bleed screw, so you can almost completely gravity-bleed the car before starting it. Turn the car on, let it warm up bit, until it is about half way up the temp gauge, bleeding periodically as it warms up. This should get you bled. If not, you've probably got an HG issue. Mine had a very slight leak that didn't show up under cooling system testing or the exhaust gas test, and I couldn't see where it failed when I fixed it. But it was just enough to put air in the system and eventually make it boil. Turbo boost was lifting the head, I'm pretty sure.