Community Forums

Varyk · 08-02-2021, 09:33 AM

Quote:

Originally Posted by neub

As rusty as that petcock is I personally wouldn't mess with it but rather pull the lower radiator hose to drain and flush the radiator. At least this way you dont risk damaging the radiator and have to pull it to be repaired or replaced

Removing the lower hose is a great suggestion, thank you. I was planning on taking off this hose when I just lucked out and it looks like repeated sprayings of WD-40 since yesterday finally loosened it.

I was very careful with the petcock and just tried a few times to gently turn it since 6 o'clock, but just now when I went to check once more, it turned out very smoothly and coolant began draining, and turned back in smoothly and the draining stopped.

Can i ask, the lower radiator hose, it's the large, maybe 2-in. diameter rubber hose plugging into the bottom of the radiator?

Thanks for everyone's help, WD-40 is fast becoming my closest friend on these little jobs.

Varyk · 08-02-2021, 09:35 AM

Quote:

Originally Posted by Chelu

And after successfully draining the old coolant, I would recommend replacing that rusty petcock valve before filling your radiator with fresh water/coolant.

I'd like to replace it. I should just be able to unscrew the fastener behind the handle that holds it onto the radiator, right?

thanks

carybosse · 08-02-2021, 09:38 AM

Quote:

Originally Posted by Varyk

Removing the lower hose is a great suggestion, thank you. I was planning on taking off this hose when I just lucked out and it looks like repeated sprayings of WD-40 since yesterday finally loosened it.

I was very careful with the petcock and just tried a few times to gently turn it since 6 o'clock, but just now when I went to check once more, it turned out very smoothly and coolant began draining, and turned back in smoothly and the draining stopped.

Can I ask, the lower radiator hose, it's the large, maybe 2-in. diameter rubber hose plugging into the bottom of the radiator?

Thanks for everyone's help, WD-40 is fast becoming my closest friend on these little jobs.

Yes, roughly 2" diameter hose is what we are talking about.

Typically, radiator is going to have a fairly large hose at top and bottom for flow of coolant. You may see some very small lines also feeding the bottom of the radiator, these typically are for automatic transmission cooler and maybe an oil cooler? Much smaller lines, may be hard piped (tubing) or hard piped to the radiator but convert to a short piece of small diameter hose to allow for the vibrations to not break a hard pipe.

carybosse · 08-02-2021, 09:42 AM

Quote:

Originally Posted by Varyk

I'd like to replace it. I should just be able to unscrew the fastener behind the handle that holds it onto the radiator, right?

thanks

The fastener is part of the petcock. Hopefully this link can help you understand what you are looking at.

https://www.autozone.com/cooling-hea...E&gclsrc=aw.ds

The fear all of us have is that you go to unscrew it, and it is so rusted to the radiator that you damage the radiator beyond repair.

Be VEWY, VEWY, careful.

Roy-c · 08-02-2021, 09:48 AM

Looking at the pictures, the lower section of some of the radiator fins are corroded away. I would suspect that the radiator is on its way out. Have a competent radiator shop look at it. That rusty petcock may be the least of the problem. At least run your finger lightly across the fins. if they crumble then the radiator is toast. But be ready for a radiator replacement as it could start to leak. If that happens it was really toast.

tcg · 08-02-2021, 09:49 AM

If the drain is working and doesn't leak I would also not mess with it unless you knew a replacement radiator was readily available.

There are radiator shops that could easily rebuild the one you have if you can get the radiator out easy enough. Now might be the time or be sure you know where to get one should the need arise.

TXiceman · 08-02-2021, 09:58 AM

A very rusty petcock to drain the radiator. You will need to remove it and replace it with a new one. With some WD40 or PB Blaster you may get that one to work. You should open it with the wings and probably a pair of channel-loc pliers. The fluid will drain through the center hole.

If you can't get it open, use a open-ended wrench on the hex behind the wings. Put the new one in with TFE tape and put a little grease on the pet-cock threads.

Ken

R.Wold · 08-02-2021, 10:05 AM

Quote:

Originally Posted by Old-Biscuit

YES....but they are left-hand threaded
Turn counterclockwise and they screw IN to Open
Turn clockwise and they screw OUT to Close

Think of it as a really cheap, flimsy, delicate, rusted faucet. Maybe give it some penetrant lube before trying to open it.

And it falls under the old axiom: Lefty loosey, righty tightly

And yes, I am certain without reading this thread that I just repeated about 80% of the responses.

carybosse · 08-02-2021, 10:59 AM

Quote:

Originally Posted by R.Wold

Think of it as a really cheap, flimsy, delicate, rusted faucet. Maybe give it some penetrant lube before trying to open it.

And it falls under the old axiom: Lefty loosey, righty tightly

And yes, I am certain without reading this thread that I just repeated about 80% of the responses.

Been a long time since I messed with an old fashioned petcock. The threads that attach it to the radiator are righty-tighty, lefty-loosey. However, to drain the radiator, I believe the drain function has left handed threads.

I guess the other thing I would suggest is that if you decide to open the petcock and drain out that way, put a wrench on the hex portion of the petcock to prevent any stress on the radiator.

Another thought - a radiator that old probably has a lot of corrosion inside, that corrosion could block the drain at the petcock and end up requiring the removal of the entire petcock to drain.

I almost always like to flush my radiator with lots of fresh water, but this old of a radiator may not take kindly to an internal bath and may create all sorts of other issues.

jonmurray · 08-10-2021, 04:36 PM

Quote:

Originally Posted by Varyk

I'd like to change the engine coolant in my 1980 Winnebago Brave. When I looked at the bottom of my radiator, I found what I assumed was the drainage bolt, and it has a small bowtie like protrusion coming out of it.

1) What's this little bowtie(pictures attached)? Did it use to be the branches for a heat sensor.

2) Does that look like the drain bolt? It looks like I should be able to get a small wrench in there and undo it so that I can drain the old coolant.

3)Thanks for any help.

I recommend some penetrating oil before you try to move the drain Cock. That's what it's called. It screws in to drain

Old-Biscuit · 08-10-2021, 05:08 PM

SEE POST #15

OP Opened/Drained/Closed Petcock---worked just fine

Kenvb · 08-10-2021, 05:18 PM

i would remove the rad and take to a rad shop for a rebuild..unless your not going far and have a real good towing membership. In 2018 when i rebuilt 72 Winny Brave,,i bought a new rad from Amazon for a 73 Dodge 1 ton truck. for $150 not sure what your powertrain is.like Carybose says,theres not many rad shops around anymore..

TB673 · 08-10-2021, 05:35 PM

Not knowing the age, but it might be a good idea to replace the upper and lower hoses while the cooling system is empty.

Tim

NeilV · 08-10-2021, 08:05 PM

When concerned about the stability of an old radiator and deciding to disconnect a lower hose to drain the system sometimes your better off disconnecting the hose from the more sturdy connection on the engine block rather than the sheet metal fitting on the radiator. Watch out for the loose coil spring that some lower radiator hoses have inside them to prevent them from collapsing when the engines are running at high rpm since the lower hose is usually connected to the suction side of the water pump.

A light flush with a mild mix of white vinegar and distilled water may be helpful too as on an old radiator you may not want to resort to one of the more caustic commercially available flush products on the market.