eschoendorff

Hey guys,

I went ahead and drained my cooling system so that I could install new heater hoses. Hoses went on just fine. No real issues until it was time to refill with coolant. I checked all my hose connections and started slowly pouring coolant into the surge tank. I opened the T-stat bleeder and kept slowly filling the system. I got coolant all the way to the top of the fill neck and still no coolant was coming out of the T-stat bleeder. So I squeezed the lower radiator hose and I could hear air moving through the bleeder.

I needed to check on a couple other things, so I left and came back a few minutes later. Coolant was very slightly low, but even after topping it off, no coolant came out the bleeder!

No matter what I do, I cannot not get coolant to come out of the bleeder. I seem to be completely filled up.

BTW -
The brass bleeder screw at the throttle body is a little deformed and I am afraid that if I get it open, that I won't be able to close it down again. Anyone know why they went with a slotted screw instead of the 7mm hex like the other one? Is it a big deal if I only open the T-stat bleeder and not the TB bleeder?

Thanks!

Ed

don hall

The LT1 is self-bleeding...... forget about the bleed screws.
Just fill the reservoir, and the overflow bottle to the 'low' level.

Run the vette at op temps for a few minutes, or until the fans operate (225)..... shut the engine down.... check the overflow bottle dip-stick to see if expanded coolant entered the bottle. There is no pressure in
the overflow bottle. Let the engine cool, then check the overflow bottle dip-stick again to see if a siphon occurred which would reduce the coolant level in the overflow bottle.

Remove the reservoir cap to see if coolant needs to be added. Fill as necessary. Done.

From the following link: "The pressurized reservoir is mounted at the highest point in the system, and provides a place where all air can be continuously scavenged from the coolant. Any steam and bubbles are allowed to rise to the surface, eliminating foam and providing pure liquid coolant back to the engine. Pure liquid coolant is returned to the system via the heater outlet hose connection. The pressure relief/vent cap in these systems is rated at 15 psi and is located on the reservoir rather than the radiator.

http://www.fierolt1.com/lt1_cool.htm

Ozzstar

Have you started the engine and allowed the water pump to circulate the coolant? then crack open the bleeders? If your afraid the bleeder valve that is deformed is going to break, then order a replacement. Most of the Corvette part places sell them and are readily available. Soak it with penetrant like PB Blaster or Liquid Wrench to help crack the bleed valve open. The trapped air needs to be expelled.

eschoendorff

No, it's just the throttle body bleed valve that's an issue. The Thermostat bleed valve works without issue.

For the record, I have not started the engine since changing out the hoses and refilling. The way I read the FSM, the bleeder valve is opened and coolant is added until the coolant comes out of the bleeder valve before starting the engine.

Thanks Seabright. Gonna check out that link.

eatmydst1234

Sometimes you get a hydro lock situation in the water pump. Close off bleed valve and start engine for a second or two so that the water pump turns. Then open bleed screw and finish.