Radiator Coolant: Proper Level?

[theslawdawg]

Hello Everyone,

Can someone please tell me what the proper level that my coolant should be?

I've checked my manuals (one is the 1972 repair manual) and they say two different things (at least I think it does). One says it should be an inch from the top and the other says it should be 3 inches from the top but there should also be a little arrow telling me where to fill. Of course, I didn't see an arrow anywhere but that doesn't mean I didn't miss it.

I've included some photos to assist.

Thanks in advance for the help.

[kgt]

one inch is fine. Or you can install a overflow and a new rad cap and forget all about it and not have to worry about it making a mess on the driveway...

[capev86]

first off...if you don't have an overflow bottle....get one installed pronto.

use demineralized water (dehumidifier is a cheap source)

i always fill it to the top because it will drop or run into the overflow if too high.

if filling an empty system, i use (green) coolant while it is cold and then just add demin water to refill the rad as the level drops while it is warming up. you can squeeze the upper hose (slowly and gently) to work the bubbles out.

[theslawdawg]

Thanks for the advice. Much appreciated.

Is there any place online that sells the radiator bottle? I've seen some innovative ones in this forum. Also, what cap do I need? I link or pictures would help.

Thanks again.

[Tx Firefighter]

There's no reason to get too excited about installing an overflow bottle. Once it burps and finds it's level they don't drain anymore.

[theslawdawg]

I think that's the question I've had. I have not consistently checked my radiator level since I purchased this truck in December. I admit it, I'm new at this stuff but I've learned my lesson. However, since my truck has been running great, my coolant level has obviously not been an issue. I just want to make sure I don't damage anything in the future. I filled it up an inch to the top so we'll see.

[Tx Firefighter]

Just fill it up close to the top. After the truck runs and warms up and cools a few times it will pee some out the overflow hose. After a few hot/cold cycles it will have found it's happy level and not pee anymore.

[cdowns]

overflow bottles r overrated// but if you really must , then just go to local autoparts store they carry the complete conversion , cap bottle and tubing , should b less than twenty bucks/// just keep in mind the truck has done just fine without it for 40years

[Leviticus]

Originally Posted by Tx Firefighter

Just fill it up close to the top. After the truck runs and warms up and cools a few times it will pee some out the overflow hose. After a few hot/cold cycles it will have found it's happy level and not pee anymore.

This^^

And it will let you know if it is low on coolant cause your temp gauge will have this little guy in it. Just be sure to watch your gauges like a hawk and regularly check your fluids. There is no idiot lights/bells in these old gems.

I top mine off to the bottom of the fill neck and then drive it and let it burp itself, check it again, top it off again. What it doesn't want goes in the overflow bottle.

[theslawdawg]

Got it. It's filled up. I'll let you guys now how it works out. Once again, I'm grateful for the help. Now...off to my next project.

[Legolas894]

On the back of my rad ('67) there is actually embossed lettering saying FULL COLD about 3" down from the top of the rad. I have an overflow bottle as well. Never had an issue.

[capev86]

overflow bottles r overrated

ok....i want whatever you are smoking.....

i found my radiator kept getting low on coolant until i put a bottle on. now it rarely needs fluid added. you want the system full of coolant for proper operation and the overflow bottle gives the extra room needed as the coolant warms and expands. GM was a cheap skate back in the day that's why it was an option for the few enlightened people. i will be trailer towing with my 72 burb and i don't want any issues....

[Shyguy]

Originally Posted by capev86

ok....i want whatever you are smoking.....

i found my radiator kept getting low on coolant until i put a bottle on. now it rarely needs fluid added. you want the system full of coolant for proper operation and the overflow bottle gives the extra room needed as the coolant warms and expands. GM was a cheap skate back in the day that's why it was an option for the few enlightened people. i will be trailer towing with my 72 burb and i don't want any issues....

X2 on I want whatever you are smoking, lol. It has been a long while since I had had any "Smoke".

Back in the day, mid '70s, I use to tow a travel trailer or 26' cabin cruiser with my '72 3/4 ton GMC and was concerned about coolant lose so I put a universal over-flow bottle on the truck.

I have not used one since then on any of my trucks, of course I don't use them to tow with.

I guess it is personal choice to use an over-flow bottle or not.

Danny

[Stocker]

I'm a great fan of overflow tanks... barring any problems, the radiator is always full -- more coolant (no air in the system) equals a bit more cooling capacity. And you don't even need to remove the rad. cap to check the fluid level (yes, I know it's not that hard), it just takes a quick glance at the tank.

As to the trucks not coming with tanks.... well, a lot design improvements have happened over the years. Vehicles didn't always have clutch fans (or electric fans) or fan shrouds. I remember when overheated vehicles were a relatively common sight in summer, especially in the mountains or the desert. Pretty rare to see that anymore.

[cdowns]

there is no additional cooling capacity involved// at operating capacity a properly filled radiator with a dump tube has the exact same amt of coolant in the radiator as a system with an overflow tank// the amt of coolant in the overflow tank doesnt go back into the radiator till the operating temp goes below normal and isnt needed to lower the temp