LS1GTO Forums banner

1 - 8 of 8 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
Good morning folks. I'm a longtime reader and first time poster.
I'm having an overheating issue that is absolutely baffling me. Help. Please help me brainstorm this thing.
Three weeks ago, after backing out of my parking space,I noticed a pool under where the passenger side was. I pulled right back in, popped hood and started hunting. Discovered a leaking heater bypass valve. Ordered part. Loaded car up with water, drove it home and parked it. A week later the valve came in. Replaced it. Now here's where stuff starts jacking around.. fill system up. Start it up. Begins to slowly warm up, not feeling much heat from the vents with the heat running after about two minutes. 🤔 odd. Temp Guage climbs to midway by 4 minutes. Then Temps begin to climb higher and get near 75% of the dsplay and the fans come on. That has never happened before. I have done at least 10 bad radiators, one water pump, and two thermostats on this car over 5 years,and have never had this symptom before. So I decided to start replacing my parts that have warranties. New water pump, new thermostat, new ECT sensor, same problem continues. Thinking i may have missed a connection somehow i break it down again, I confirm that I've got a pump that moves fluids, a thermostat that does open with a boil test, no visible leaks . Ie Water pump weeping, radiator leaks, etc. I reassemble with no thermostat, top off, and the same results happened. In an effort to start eliminating sections, I've pulled my line that runs from the upper radiator to the heads, poured water in there and it fills system, ive pulled each hose to do the same and all my hoses are able to flow water. I've shot a bunch of water into the block through the upper ports behind the water pump and get a heavy return from its corresponding lower. I really feel like I've got circulation. However I still don't get hot air from my heater, nor do my hoses get warm.
I have no confidence in my local tech who was not able to help with a key programming in the past. Im stumped. What do you guys think?
 

·
Registered
Joined
·
6 Posts
Discussion Starter #2
SMH. This was an air pocket.
So i decided to remove and reattach everything. I filled the system using the hose from the radiator to the heads, elevated it and began to fill. As the water level in the block rose to the upper output on the water pump, i attached the hose and continued to fill, once the water level made it up to the lower input on the heater core, i filled the heater core with a hose, then attached the lower hose, topped off hater core attached upper output hose, then filled system using that head hose until the level topped off the radiator. Attached final hose, radiator cap, and then ran it all to start hunting down which hoses needed tightening down. Ran all for about 20 minutes with heat blowing hot as he'll, and no overheating signals. My guts telling me I had a bubble in the heater core and another in the driver side head that were corrected when I filled using that goofy technique. 🤷‍♂️
 

·
Registered
Joined
·
1,111 Posts
Glad u found it. Was gonna suggest that. Usually having the car on an incline and filling the block through the upper hose gets it in the first try
 

·
Registered
Joined
·
6 Posts
Discussion Starter #4
What kind of blows my mind is that this is the first time I've ever had that symptom, and I've had the cooling system dry at least 15 times in 5 years, but never touched the heater core before. With quantity of post available for that topic, I'm kind of surprised I've never encountered it before. I guess my lucky streak ran out. 🤷‍♂️
 

·
Worthless reject member
Joined
·
45,479 Posts
I wonder if holding the heater control valve open and running the engine while topping off the radiator or surge tank would have helped.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #7
Perhaps it could've. But I just topped off again and ran another heat cycle. Feeling better already.
So I've had a little time to think on this one. I do not believe it would have made any difference. The valve itself has a default position of being open and feeding the heater core. It stays open, unless the interior temp dial is rotated to cold. At that point a vacuum is pulled from somewhere that closes the valve and causes the coolant to not be directed to the heater core. A Bypass. I think I had a Ford that required that process though....

4th heat cycle now, no top off at the radiator required this time. Repair is doing fantastic 👏.
 
1 - 8 of 8 Posts
Top