I finally got my nova to start. The car had starter issues that I think have been solved. Now to my next dilema. After firing up the car I heard a hissing noise and like rushing water going back towards the radiator. I have found no leaks from hoses and or fittings.
These parts are new, three row radiator, upper and lower hoses, themostat. The heater hoses from the manifold to the bottom heater fitting and the water pump to the top of the heater core. Here is a thing that I found odd. The temp gauge did nnot move after runniing for 5 mins. But did move when enginge was shut off. The gauge registered 140 degrees. Any ideas on what may cause this?

Thanks

Jerryt

now that it's cooled down, check coolant level again. might need topping off.

where's the temp sender located ?

Look at your A/C-Heater box water outlet under the passenger side inner fender. If the heater core has sprung a leak (not having been used in summer) having pressurized coolant running through for the first time in a while the water will exit there. The heater core is just a small brass radiator and subject to even more corrosion as it sets up unused most of the year.

Big Dave

I think Dave is right on this one. Mine does the same thing. My heater core has a tiny little leak, hisses a lot (must be mad from not being used for so long:eek:) but barely leaks.

Alex

The temp gauge is in the manifold. After running the temp registered 140 degrees. I will check the coolant level, and the heater core. Seemed kinda odd because previous starts it did not make a sound. Would a sticking thermostat be part of the problem also?

Thanks
Jerryt

jerryt,I don't think you let it run long enough to open the thermostat. If it only got up to 140, that isn't enough. Most thermostats are 180 or 190. It probably has air in the system and is not full of coolant. That is why you here hissing noise. Like Shifty said check your coolant level again.

I checked coolant level again and it was down. I topped it off. I also checked the heater core and found no leaks. Looked for any sort of water damage on carpets and all around the heater core . Sounds like air in system still. The temp gauge did not move while I ran the car. Then it moved to 140 degrees after I turned it off. I will start car again after charging battery. Any idea on how long I should run car till the air is out of system?

Thanks
Jerryt

let it reach operating temp... 180* minimum, 195* or so maximum, then shut it down and let it completely cool down. then recheck coolant level again. once filled properly/air out of system, start it up and let it run a while at operating temp...

also, after the initial run at 180/195* after it cools that'd be a good time to check/retorque exhaust & intake manifolds etc ;)

Will do. This is a great web site. Thanks much. I will let you know how it goes. Now if I can just get more time from the dwife and kids. haha

Thanks
Jerryt

I got my car to start today and bad things happened. I ran the car for about 5 minutes, and the temp gauge jumped from 100 to 230 degrees. I immediatley shut off the engine.
Then i saw transmissionfluid coming out of the filler neck (not a lot but enough). The motor and the manifold was hot, but not the radiator and hoses. The radiator was rebuilt into a three row. The waterpump and thermostat are new. When I checked water level it was only down about 1 inch. I had starter problems so I also had to replace the flexplate. The only recent changes are the radiator. Any ideas on this?

Thanks
Jerryt

You had it built into a 3 row? Did they loosen the trans cooler inside the radiator when they done this? I'm not sure about the temp problem, maybe the thermostat is stuck closed. Sounds like the radiator may need pulling and the trans cooler inside checked out or just put a external trans cooler on it. You may need to change the thermostat even if it is new. Check the trans fluid for water now.

the new thermostat, new or not, is bad. replace thermostat. you can check the thermostat on your stove in a pan of water and a thermometer... watch it as it reaches the rating of the thermostat... if it's a 180* stat it should be open by that temp...

recheck fluid level of trans, did you add fluid or change fluid at any time during all the work you've done... could be over filled.

Sounds like a ruptured internal oil cooler in the radiator (may have lost a solder joint in the rebuild if too much heat was used to solder on the tanks. Water (alcohol based coolant) in the tranny is bad; you need that checked out pronto.

If the cooler is bad you would have to plug the cooler holes as well as using an external cooler as if tranny fluid can escape into the tank then water can escape out of the radiator by way of the transmission cooler lines and boil in the trannies case (which isn't water tight above a fixed level).

Big Dave

It is also possible that you have the thermostat in backwards.

It is also possible that you have the thermostat in backwards.



yup, the pointy end points UP ;)

Well I got my car to start. And the same problem happened. But I did notice that there was water leaking from the bottom tranny coolier opening. This car has a external cooler on it now (previous owner). I replaced the themostat pointy side up.The car ran for 5 minutes and the gauge did not move. I checked the coolant temp and It was not hot. Any ideas I am going to pull the radiator after I call the shop that rebuilt it.

Thanks
Jerryt

Here is a thing that I found odd. The temp gauge did nnot move after runniing for 5 mins. But did move when enginge was shut off. The gauge registered 140 degrees. Any ideas on what may cause this?

Thanks

Jerryt

It is normal for temp to rise after engine is shut down. There is no fan moving air (unless it's electric) And there is no water moving thru engine.
As for the hissing sound. I think what you were hearing was the water going thru the empty heater core for the 1st time.

Let the car run with the cap off to see if the water is flowing thru the system. What is the outside temp. where you are at? It might take a very long time to get it to operating temp if it's cold out. You can try putting the car in gear with your foot on the brake. Sometimes it will get to temp quicker this way.

Also if you are running a mechanical fan try putting some card board in front of the rad to bring up temp.

Where is your sending unit located at?

Not sure if this sound is just water going thru the heater core. The outside temp was around 71 degrees. And the ssending unit is in the manifold. I am runninga mechanical fan. I figured that running the motor for about 5 mins would have made the temp read something.

thanks
Jerryt

I am still having problems with cooling. I just spoke to the shop that rebuilt my radiator, and they think the thermostat has not opened. I started the car and ran it for 5 mins. Then the gauge jumped to 210 and I shut it off. The bottom hose, heater hose were warm. The motor made a sizzling noise. But the top hose was cool. The radiator shop said sounds like a air bubbble is trapped and not allowing the dwater to go thru the therm and into the radiator. They said that 250 is the danger point. Waht do you all think of this?

Jerryt

i think you should remove the thermostat and test it as commented on in a previous post. if it doesn't open as it should then it should be returned/exchanged where purchased or replaced. prior to replacing IT should be tested to confirm it's working.

for the test of the cooling system, leaks etc then a thermostat isn't "really" required... but depending on your location, temperature wise, the engine may not actually reach operating temperature... the thermostat will be then needed.

i don't recommend driving a car without a thermostat... it helps the engine reach operating temp for optimal temp/performance etc.

JR

They said that 250 is the danger point. Waht do you all think of this?

Jerryt

I pegged an Autometer mechanical guage and broke it. The tech with Autometer said it was probably at least 280 degrees. Fixed the problem with the cooling system, replaced the guage and the engine was fine.

An old trick to keep an air bubble from getting trapped under the thermostat is to prop it open with an asprin. As the coolant level rises air can escape past the t stat. The coolant dissolves the asprin; you can also drill some small holes in the flange.

Phillip thats a pretty cool idea. I was thinking of testing the car without the thermostat. I have tested it for opening rate in a pot of hot water. I will let you know how it goes tomorrow.

thanks
Jerryt

I started my car up again. I ran the car for 7 minutes, and watched the gauge go to 205. Then the gauge dropped to 180 degrees, the thermostat finally opened.Also while dooing this I kept topping off the radiator. I then shut the car off, and still had the engine making sounds like the motor got hot. I checked the water level and found the radiator was about half full . Is this still normal? I never had a chevy do this before. I am going to wait until the motor cools and top it off. is there something I am missing?

Thanks
Jerry

half full is only half full... fill 'er up and see what she does ;)

I checked the water level and found the radiator was about half full . Is this still normal?

Thanks
Jerry


Because the t-stat opened it filled the block. That is why the rad was low.