97 RedSS

Been working on an overheating issue with my car and I've followed shoebox's tech page to a "T" and I'm not having much success...

I opened both bleed valves and filled the radiator to the top until all bubbles were gone and made sure the overflow was to the FULL COLD line..

Then I started the car and I had to put the radiator cap back on because the coolant started coming out of the radiator after 30-45secs...(possibly due to having an electric WP??)

I let it idle for about 15mins and nothing came out of the bleed valves. The temp was around 190 and fans were running. Temp stayed there until I started holding the rpms to around 3k for about 3-5mins, then the temp went to around 200-210 and I started seeing small squirts of water coming out of the lower bleed valve but it would never come out a good steady stream. No water ever came out of the upper bleed valve, which makes me worry????

After about 7-10mins after holding the rpms at 3k, I started seeing coolant and steam coming out of the overflow tube cap...keep in mind the temp never went far above the halfway mark(210 or so). I went ahead and turned the car off and I could hear the coolant "boiling" in the radiator and near the overflow resevoir.

Anyone have any suggestions/opinions to solving my issue?

I have already installed a new 18lb cap.
I'm thinking I should check the thermostat and make sure it is opening...

Thanks

Cody

shoebox

There is really no point in you holding the RPMs high. It's not going to make any difference in flow with an electric pump. If there is nothing coming out of the bleeders, you still have air in it.

Check the radiator level when cold. If it is not to the top, open the bleeders and fill to the top. Close bleeders. Put cap back on. Run engine to operating temp and check for air with the bleeders. Keep repeating until coolant comes out of the bleeders with it at operating temp.

97 RedSS

Thanks Shoebox....

powerslide350

DONT open the bleeders while the engine is running. Im not sure if thats what your doing
, but if you are... DONT or your just sucking air into the system.

Is it the original radiator?

rbaksi

when I did mine I let the radiator cap sit open as it ran and when it went down a bit when the thermo opened I topped off the radiator. Bubbles came out from there and eventually the bubbles slowed and no more bubbles came. Put the cap back on and cooling system works awesome now. (this is what I did after I changed out my water pump)

97 RedSS

Did as shoebox stated and it ran for about 30 mins and never got above 170.

removed cap, opened bleeders- filled with coolant and let the bubbles evacuate.

closed bleeders and placed cap back on

started car and let it run 5 mins until it got to operating temp.

opened both bleeders, at first it spit alot of air bubbles but after a few mins it starting spitting alot more water.

It never spit a steady stream out of the lower bleed valve and the upper never spit anything after 15mins of runtime, so I went ahead and shut the motor off and will go at it using the same method again tomorrow after it is cooled.

Temp NEVER went above 170 though..

Hopefully tomorrow I'll be able to top the radiator off and get it up to run temp and open the bleed valves and get a good steady stream of water coming out..

shoebox

Nope, you're not sucking in any air when the system is at operating temp and under pressure.

96 Z 28

I can tell you I had to bleed mine about 10 times over when I changed my Thermostat & Sensor....

I even got a steady stream through the bleeders a few times, but there was still air pockets

But just keep bleeding until you get the air out

MislMan

Just a quick recap .... at last attempt you bled the system, ran it for 30 minutes and temperature stayed below 170.

Sounds like things are working to me. I'd drive it around and see what the temperature does. I see no pressing reason to worry about water coming out of the bleeds.

Later ... Larry S.

97 RedSS

Update from today-

opened bleed valves and added water until radiator was full, closed bleed valves and replaced cap

started car and let run for 10mins until it got up to operating range(temp stayed below 175)

opened both bleed valves, after a few seconds, the lower bleed valve spit out some bubbles then it shot out a good steady stream of water until I closed it off after 45secs.

the only thing that concerns me is the upper bleed valve still hasn't spit ANY water out at all. I even removed the bleed screw and still no water came out. I don't think it's clogged because I could shine a flash light in the hole and see water.

Although temp is staying below 175, I want to be 100% sure I get all the air out of the system before I head out in the Dallas stop and go traffic!

Thanks everyone!

Cody

6SpdLT1Z

You said you added water.... does it have a 50/50 mixture? if not it could boil quicker and/or crack your block in the cool.

so it seems to be running good now that you bleed the air?

97 RedSS

I add close to the same amount of coolant vs distilled water so I have a proper mix ratio.
I don't see any issues with it overheating but then again, the temp has dropped into the 80's here so it won't be pushing the cooling system hard like it was a few weeks ago when it was 100

97 RedSS

Arghh...Been driving the car 1x every 2wks or so for the last 8mnths and haven't had any issue, until today! Temp was 96 here and I drove it to work. The whole 20min drive the temp never went above 185. When I got to work and parked, it waited about 15-20secs after I turned the key off and it proceeded to boil-over at the overflow resevoir I could hear it bubbling in the radiator..

Anyways, why would it do this only when I park the car?

When I got home I let the car get up to running temp and opened both bleeders again and it spit some air out and would start shooting a stdy stream ever now and then. Still, the other bleeder on the smaller hose will NOT spit any coolant out of it.

Anymore tips?

I will check the level again tomorrow and repeat the bleeding procedure but not sure it will help because I can never get anything out of the other bleeder. I believe it runs to the heater core, could it be clogged up?

Thanks

Cody

97 RedSS

Think I found the issue!! Came from an old post! If you are having this problem check this out...



I have seen this happen before when a new radiator was installed on an LT-1. Check the coolant hoses that are under the radiator cap to be sure that you didn't mix them up. The upper port should have the hose going to the overflow tank connected to it. The lower port should be connected to the throttle body or to the vent tube that runs to the back of the head if you have performed tha throttle body bypass. If these hoses are mixed up, the overflow tank will get pressurized coolant from the engine and cause it to boil out. Just my 2 cents...

Brian