Upper radiator hose replacement

[tbirdmike63]

My upper hose needs replacing, the shop manual says to drain the radiator, is this necessary, is there an easier way? Any help would be much appreciated. Thanks!

[jopizz]

How much coolant is in your overflow tank. If there's not much in there you can pull off the hose from the radiator and just let it spill into a pan. Since you're not reusing the hose you can also just cut it with a razor knife and let it drain out slowly to minimize the mess.

John

[scumdog]

You will have to drain it a bit to get the coolant level below the level of the hose you're replacing.

Thankfully there is a little tap gizmo at the bottom of the radiator about 15" below the top hose fitting on the radiator.

How you catch the resulting coolant I'll leave to you but a tray with a large surface area would be a good start.!

[tbirdmike63]

Thanks, do you think my local Napa auto parts will carry the hose that I need?

[jopizz]

Thanks, do you think my local Napa auto parts will carry the hose that I need?

They probably won't have it in stock but they can usually get most parts within a few hours. I would check with them.

John

[tbirdmike63]

Once I get the new hose on and top off the radiator, is there a process to purge the air from the system? Thanks!

[Ladysmith Bob]

If you drill 2 - 1/8 holes in thermostat it will allow air to burp from engine system.( in flat body of thermostat )

[jopizz]

Once I get the new hose on and top off the radiator, is there a process to purge the air from the system? Thanks!

Only fill the overflow tank with coolant until it covers the very bottom. Don't fill it to the top. Then run the engine with the cap off until the thermostat opens. Use a flashlight to look into overflow tank. You will see the coolant begin to rise and fall. Let it run for a few minutes until you see there are no bubbles in the coolant. After it cools off check the coolant level in the overflow again and add if necessary. It should be about 1/3 full. It's important not to overfill it. You need room for it to expand when it gets hot.

John

[tbirdmike63]

I put the new hose on, added some coolant, let it run, but I couldn't get the temp. To go over 181 degrees, I think I have a 190 degree thermostat, the coolant was bubbling and moving around, so I shut off the car, do you think it's ok? Thanks!

[Ladysmith Bob]

I probably should have made the rational behind drilling holes in thermostat available, but it was early in the morning and I wasn't quite sharp yet.
The common thought is that sometimes an air pocket will be trapped in motor cooling jackets and be dislodged by a sudden bump, roll, or angle of the car when driving. If this air pocket is large enough to fill the void of the thermostat temperature spring the water will keep getting hotter and hotter and the air pocket will not transfer enough heat to open thermostat.
By drilling these holes you allow this air to escape without changing the performance of the thermostat.

[jopizz]

I put the new hose on, added some coolant, let it run, but I couldn't get the temp. To go over 181 degrees, I think I have a 190 degree thermostat, the coolant was bubbling and moving around, so I shut off the car, do you think it's ok? Thanks!

You probably didn't let it run long enough. Let it run until all the bubbles are gone. If the coolant was moving then the thermostat opened.

John

[tbirdmike63]

Yeah, I replaced the coolant that i took out, it was pretty nasty, I figure I will drive the car, get it up to operating temperature and watch the temp gauge, then add more if needed.

[jopizz]

I probably should have made the rational behind drilling holes in thermostat available, but it was early in the morning and I wasn't quite sharp yet.
The common thought is that sometimes an air pocket will be trapped in motor cooling jackets and be dislodged by a sudden bump, roll, or angle of the car when driving. If this air pocket is large enough to fill the void of the thermostat temperature spring the water will keep getting hotter and hotter and the air pocket will not transfer enough heat to open thermostat.
By drilling these holes you allow this air to escape without changing the performance of the thermostat.

In Thunderbirds it's not much of an issue because the overflow tank is so far above the intake manifold and radiator. Air bubbles will always find the highest point. In modern cars it's a much more common problem which is why they have bleed valves.

John