Cooling system is driving me CRAZY STILL!!!!!

[Nightmare Bronc]

I did not read all but do you have the reverse rotation water pump?

 

[Socal Tom]

Sounds like a leaky head gasket to me. The fact that it continually bleeds off pressure and leaves the radiator low says that you probably have a small leak from a cylinder. It should not be running 210 without a thermostat.
Tom

 

[DirtDonk]

All cylinders tested between 130 and 135
Did the block test and it come up negative
Removed t-stat and tested ok

Ok, so far so good.

I put everything back together but left out the t-stat. I have great flow coming into the radiator.

Good again.

I am now getting coolant overflowing the overflow tank, and a steady stream of small bubbles coming up in the overflow tank.

What? Why is it flowing into the overflow tank? This is with the cap off, or on? When you say overflow tank, you're referring to a separate expansion tank hooked to the filler neck, right? Or are you talking about the side tank of the radiator, looking down through the filler hole?
First off, if you're talking about a separate tank, the coolant shouldn't even be flowing into it.
And the steady stream of bubbles does not bode well either. With luck, it's just air that you've got trapped somewhere. If not though, not good...

With n t-stat I drove it around for a while and the temp got to about 210 and stayed there.

Did you mean to type "no t-stat"? Or did you mean to say that you put the thermostat back in?
As was said, 210 is a bit high for no stat, but it's not that big a deal if you have one in. Still on the high side, but you don't even know if the gauge is correct yet.
You should verify the gauge while you're doing all this, just so you know what you're dealing with for sure.

Nothing is making sense to me. What should I be looking at now?

Was the upper hose getting sucked inward, or pooched outward, before, when you were experiencing that pressure issue? And was this with the cap on, or off?
If off, then you've got some kind of blockage in the radiator itself. With the cap off and the radiator at ambient pressure, your pump would have to be sucking the snot out of things to get a reaction on the hose.
Or the hose would have to be old and totally decrepit, which it doesn't look like it is.

Good luck. Keep pluggin' away. But you may need to re-do that gas-test to see where the bubbles are coming from and why you're losing a gallon and a half per ride. White smoke and missing coolant "usually" means only one thing.

Paul

 

[kinder]

A couple of months ago I went through the same troubles and had similar symptoms; too much pressure, bubbles, higher than normal temps. The exhaust gas in coolant test may take a couple of times before it pops positive. Run the test after you've driven it with the coolant system closed and put the test kit on immediately after removing the cap. If you've run the pressure test as well how long did you leave it on, 1-2 hrs or overnight? My 2nd leak only showed with a warm engine, so the cold pressure test didn't reveal anything. Additionally, pull the plugs and get a good look at the pistons, do any of them look cleaner than the others? The small leak I had steam cleaned a small spot on the piston. If it ends up being the head gasket, replace both of them at the same time even if you think only one side is leaking. A good piece of advice I wished I would have heard earlier.

 

[forestguy]

OK, I will try and answer all the questions

I am still running with no t-stat. Doesn't seem to be getting warm at all, stays about 120. I only got the small bubbles out of the overflow tank after it got up to 210 with the t-stat out.

 

[Broncobowsher]

I am thinking head gasket as well. Leakdown tester is a good thing. Not really looking for leakdown numbers, but put the highest pressure you can on top of the pistons and hold it there for a few minutes. Do this with the radiator filled. When you get to a cylinder that you start getting water to rise in the radiator you have found where the cylinder pressure is making it to the cooling system.

Really that is the only way that you can be forcing air (the steady stream of bubbles in the coolant) into the cooling system.

 

[75junebug]

If you recently replaced the heads, and followed the service manual guide to torquing, instead of Felpros guide that comes with the head gaskets, you can get a leak as it warms up, but not when it is cold.
It sounds to me as though you may have a waterpump with the wrong rotation installed. You may want to check that out. It took me forever to burp my 351 when I first put in in. At idle, you should be able to leave the cap off, and see a steady flow thru the radiator, after the Tstat opens

 

[forestguy]

I didn't know there was a different torquing sequence for different gaskets. That is exactly what it is doing, once it warms up, it acts like a head gasket leak. But when cold, no issue.