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So recently last month purchased a 77 Corvette stingray recently got home for a small trip less then 40 miles one way wife parked it I went to go to the store couple hours later there's a squealing sound it sounds like the heater core is rattling itself to death after parking it there is radiator fluid on the wheel wells and other areas no fluid in the radiator it looks like but the reservoir is still full
Last edited by Kdavis2271; Jul 31, 2025 at 09:53 PM.
I had the same problem on my 77 . If you pull the top of the overflow bottle off the siphon tube can fall off . Then the rad can't pull it back as it cools .
I've never heard of a heater core rattling. But I'm kinda new at this.
I've owned a 77 Corvette since Christ was a Corporal.
I personally have never had the pickup tube inside the overflow bottle come off. But certainly its possible.
Easy enough to check.
My advice, fill the rad. Run the engine with the rad cap off and heater turned on full hot until the thermostat opens. Top up as necessary. Make certain that tube inside the tank is indeed in place.
If the overflow bottle is over filled it will spit coolant onto the inner fender.
Once everything is filled as it should be. Drive car and keep an eye on everything.
As per a heater core rattling??? Air in the lines perhaps? I just don't know. Make certain that the vacuum controled hot water shut off is properly connected and working.
see what happens. Doesn't sound like you have any history with this car.
Difficult to trace noise on these cars. A squealing sound? Better check play in your water pump. My low mile original '75 started to make a racket under the hood recently, which turned out to be the (original) water pump. Not a bad lifespan for a 50 year old pump. I had it rebuilt by a guy here and the noise was gone. pretty easy to replace. FWIW, it never leaked. The only leaks I had were the heater hoses, which I blocked off at the water pump, and the coolant reservoir which had a crack at the base.
I have never heard of a heater core making noise.
Seems OP owned this '77 C3 about month or 2; (understandably) probably KNOWS little of its true-complete history.
All corvette water pumps have bearings & seals which Require lubrication.
Antifreeze is designed to provide that Lubrication (as well as boil-freeze protection).
If/when cooling system overheats, it may boil over or push most volume into overflow bottle; which ends up wasted on ground. If, (as smilie suggested above) the siphon tube is broken or dislodged, the coolant system may run dry. If pump runs without lubricant it will likely squeal. And, if pump's bearings & seals are dry and seizing, the pump's fan belt also may squeal.
Suggest OP perform a complete flush And heavy-duty chemical cleaning of entire liquid-containing cooling system. Also, replace water pump, thermostat, radiator cap and any damaged or missing parts of the coolant overflow-recovery system. Refill with a 50-50 mix of quality antifreeze concentrate and distilled water.
As you can see, some posters like to throw parts at problems using a blank check, from you.
Diagnose. Diagnose. Then diagnose some more. It's free.
You have no coolant in the Rad.
Where did it all go? Is the carpet on the passenger side soaked?
That would explain a lot.
You mentioned wheel wells. Which one? Do mean inner fender wells?
If the right front is saturated, you likely blew a heater hose. When that coolant sprays, it makes all kinds of racket hitting fan blades, A/C comp, belts, etc.
I have discovered it was the water pump and have been working with my veery limited supply of tools (deff using some MacGyver status tools ) for a half day waiting on parts an some new wratchet an socket set......now bigger issue while giving the thermostat the attention it very much so needed i may or may not have smacked my pinky knuckle off the Lil sensor thing on the top while trying to loosen the bolt an it suddenly snapped fml
That's OK. I see a few things that are not factory stock in your engine bay. Just delete the stupid thermo vacuum switch and move forward.
here's my 77. See any thermo vacuum switches?
When the pics were taken, had you already started disassembling the fan from the pump? If not, where are the nuts holding the fan clutch to the pump/pulley? Speaking from experience, even if the clutch hub is just loose it can make quite a rattling racket.
when the pics were taken, had you already started disassembling the fan from the pump? If not, where are the nuts holding the fan clutch to the pump/pulley? Speaking from experience, even if the clutch hub is just loose it can make quite a rattling racket.
(The fan pulley nuts and locking washers laying on chrome air cleaner lid)
I still think you blew a hose on the passenger side.
Control arms are flooded with green coolant.
Waterpumps usually do not do that. But the surrounding hoses will.
When a W.P. is dyeing, usually the weep hole under the shaft dribbles.
Then, the shaft bearing starts to play games. The fan will have excess play in the blades.
And sometimes the gaskets between pump & block will weep.
But never seen one spray. (like a hose)
Last edited by HeadsU.P.; Aug 3, 2025 at 05:51 PM.
When the pics were taken, had you already started disassembling the fan from the pump? If not, where are the nuts holding the fan clutch to the pump/pulley? Speaking from experience, even if the clutch hub is just loose it can make quite a rattling racket.
yes I had its been replaced not i have a few more issues such as that noise still coming from the heater core area I have a video but it won't let me post it an now my wife has found an unknown fuse of power relay underneath the passenger side console
(The fan pulley nuts and locking washers laying on chrome air cleaner lid)
I still think you blew a hose on the passenger side.
Control arms are flooded with green coolant.
Waterpumps usually do not do that. But the surrounding hoses will.
When a W.P. is dyeing, usually the weep hole under the shaft dribbles.
Then, the shaft bearing starts to play games. The fan will have excess play in the blades.
And sometimes the gaskets between pump & block will weep.
But never seen one spray. (like a hose)
It was all over the bay and coming from underneath
That's OK. I see a few things that are not factory stock in your engine bay. Just delete the stupid thermo vacuum switch and move forward.
here's my 77. See any thermo vacuum switches?
I've attached the updated photos since I've done the pump the heater core area still makes a god awful noise tho This is after i broke the lil nips off the thing that was on the thermostat This is where the noise is i have a vid but it wont let me post it
I've attached the updated photos since I've done the pump the heater core area still makes a god awful noise tho
This is where the noise is i have a vid but it wont let me post it
Post it to your YouTube account and link back to here.
As pspicci mentioned way up in #6, the heater core noise may be the heater/AC motor or squirrel cage fan. Try pulling out the Heater A/C fuse to see if the noise goes away.
Post it to your YouTube account and link back to here.
As pspicci mentioned way up in #6, the heater core noise may be the heater/AC motor or squirrel cage fan. Try pulling out the Heater A/C fuse to see if the noise goes away.
Could use some help with cooling system problem
