skeet

Low coolant light or sensor not working. Changed anti-freeze and bled only the thermostat bleeder. After three cycles of going from 195 to 80 degrees the high mounted holding tank was always full. Does this mean there is no air trapped in the system?

jfb

Very likely there is no air trapped in your radiator, HOWEVER, Starting cool, turn the radiator cap off to the first stop, idle engine to the opening temperature of your thermostat, race engine and remove radiator cap and look into the filler neck. If there is no air, then you will see moving coolant right up to the neck of the filler. If there is air, then the coolant level will drop significantly. Replace the radiator cap and then let the engine back to idle.

Sam Lam

Sket: You can make a difficult job easier by drilling two 1/16 (.062 inch) holes in the base of the thermostat. DO NOT DRILL THEM IN THE PART THAT MOVES!!! This will allow the air to escape when you add coolant and you will not have to "pack the coolant". I have used this for years and my 89 has two holes in it. This little trick does not change the operation of the engine and makes a cooling sytem flush a breeze! If you need a picture of this, send me an email. Hope this is helpful!

sumoboy

What year do you have? I have a 94 and replaced my surge tank and had to bleed by both screws even though the tank was full. It's a pressureized system and still had some air even though the tank was full. The sensor is at the bottom of the tank.

skeet

Sumoboy - This is on a 95. I never could find the other bleeder (only found the one on the thermostat). Doesn't it make sense that if there was air in the system that each time I open the high mounted coolant tank it's level when be down some? It is now to the top of the neck.

Also, if the low coolant sensor (which mine does not work)is in this high mounted tank it would never indicate low coolant ( and thus air in the system) if the tank is full as mine is?

Also, if the low coolant sensor is bad would I still get a low coolant light when I start the car and all warning lights are tested?

RichS

You can get a new tank from Corvette Central for $50 that has a new sensor installed. As long as your not getting any air out of the bleed screw you should have it all out.

sumoboy

I only know of two bleeder screws if you have the LT1. One is at the thermostat housing and the other is located in a "tee" where the coolant from the throttle body connects to the heater return hose. They both have slotted heads which you can use a screwdriver to loosen. Try to put some rags around them when you do so the antifreeze won't run down the engine.

This site should help you.
http://h-body.org/people/projects/bu...t1%20info.html


:thumbs:

Red Dwarf

Fill the recovery tank to the "hot" mark" before you start taking it apart. Sometimes that will put out the light out & purge the system of air. Might take 2 shots.

Red Dwarf

Fill the recovery tank to the "hot" mark" before you start taking it apart. Sometimes that will put out the light out & purge the system of air. Might take 2 shots. There is another "bleed" on the pass/top side of the radiator under the rubber plug. Small dia. hose running to it.

UDLUV12

I suggest you follow jfb's answer, but when you get to the part 'where you are looking into the radiator neck, and see that the coolant has dropped significantly'...I think he meant to say, was: add coolant to the top of the fill neck, and then close the cap.

This is best done by having someone sitting behind the wheel, and pressing on the gas pedal (while in park or nuetral) to 1500 RPM's...and you doing the looking into the radiator, and adding coolant as required. Once you add coolant, close the cap at once, and have the person sitting behind the wheel ease off the pedal.

It may take you two or three times to purge the entire system. Whenever I purge my system, I let my engine cool down entirely, and then repeat the steps above.

sumoboy

He can't go by the radiator neck because on the 95 it has a purge tank by the firewall. That's where the bleeder screws come in and also it's a reverse flow system unlike the earlier years. :smash:

UDLUV12

Sumoboy,
I didn't know that about a '95.
Thanks for the reply. :crazy:

r15752

be sure the engine is cold ---not been run for a while---remove the radiator cap. set the emergency brake. start the engine . look inside the radiator when the thermostat opens you will see the coolant flowing inside the radiator. the coolant will drop in the radiator add coolant -I and 50% antifreese and 50% water- till the radiator is full. close the cap shut off the engine this should take care of your problem .them check your overflow bottle to make sure there is the right amount in there. if this doesnt't help maybe someone else has an idea. hope this solves your problem. :auto: :chevy

sumoboy

Hey, anyone who helps is a plus here. :thumbs:

Hmm...Glen Burnie, Huh.
I go by there all the time. I lived there last 20yrs


[Modified by sumoboy, 11:47 PM 3/17/2003]


[Modified by sumoboy, 11:47 PM 3/17/2003]


[Modified by sumoboy, 11:49 PM 3/17/2003]

r15752

when I emailed you I was refurring to a 89 l98. check with others to be sure the systems are the same in the 95 as they ae in the 89. thanks :auto:

skeet

I found that trick with the L98 also works on the LT1. Namely, when you speed up the engine to about 1500 to 2000 rpm the coolant level will drop and you can add more coolant than you could if the engine was at idle. Once you add the coolant you have to get the cap on fast or it will overflow out as the rpm goes down. Again, this trick does work on the reverse flow cooling system of the LT1.
Can anyone show a drawing or photo of that second bleeder valve near the throttle body. I am begaining to think I do not have one but I know the car is stock.
Lou- Thanks for the advice as well as the rest of you all.

Red Dwarf

The manual only shows one bleeder valve on the pump housing. Can't find a second bleeder valve near the throttle body. I can do a couple of scans for you of the system if you like, but can't get them off until tonight. Advise.

sumoboy

If you do it like you said on the L98...make sure you check the amount of AF in your overflow bottle because it will do what it's called overflow :nonod: If you fill it to the top while revving the pump draws it down but when pressure build up at idle the AF you topped off has to go to you know where.

sumoboy

This was posted for the ZR1 with an LT5 but basically the same way to fill correctly....nothing states to rev the engine up. :nono:

Drain, flush and refill system with new coolant as follows:

A. When engine and radiator are cool, remove pressure cap on coolant fill reservoir located at the right rear of the engine compartment by:

- slowly rotating cap counterclockwise to detent. (Do not press down while rotating)

- wait until any residual pressure (indicated by a hissing sound) is relieved.

- after all hissing ceases, press down on cap while continuing to rotate counterclockwise.

B. Open radiator draincock to drain coolant.

C. Close draincock and add sufficient water to fill system.

D. Run engine, drain and refill the system, as described in steps 1, 2 and 3, a sufficient number of times until the drained liquid is nearly colorless.

E. Allow the system to drain completely and then close radiator draincock tightly.

F. Remove and clean coolant recovery reservoir located at the right front of the engine compartment. Reinstall reservoir.

G. Add a 50-50 mixture of water and ethylene glycol antifreeze that meets GM specification 1825-M. Fill high fill reservoir to the base of the filler neck and add sufficient coolant to the recovery reservoir to raise level to the full "COLD" mark on dipstick. Reinstall recovery reservoir cap.

H. Run engine, with pressure cap removed, until normal operating temperature is reached; radiator upper hose becomes hot.

I. With engine idling add coolant until level reaches bottom of high fill reservoir filler neck.

J. Do not use pellets in LT5 cooling system.

K. Install pressure cap, making sure arrows line up with the overflow tube.

L. Check level in recovery reservoir and add coolant to full "HOT" mark on dipstick.

sumoboy

Go around to the drivers side of the throttle body and look directly below the center of it where the intake hose clamp to the throttle body is.