Thread: Coolant

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I'm getting ready to drain the coolant and install a formed upper radiator hose in place of the current universal hose. I'll also install a proper thermostat since it seems there isn't one, or it's stuck open.

Can anybody tell me about how much coolant I'll need to replace the old stuff? '32 ford with a SBC. I do not know what the radiator is.

Thanks

General rule of thumb is 2 gallons.. We won't know how big your radiator is either. Or if there is a heater.

Originally Posted by 34_40

General rule of thumb is 2 gallons.. We won't know how big your radiator is either. Or if there is a heater.

Yeah I realize you can't give me anything close to an exact figure. I appreciate your response. There is no heater. I'll start with 2 gallons and go from there.

Is there anything I need to look for in the old coolant as far as compatibility goes? There's so many types on the market now, and I don't know what's in the car now.
Thanks again.

If the old stuff is red, you'll need to match that color or do a total flush a couple times.

Any of the name brands are good. If you have aluminum parts (such as a intake manifold) make sure you read the bottle to verify it's compatible and will protect it.

Might sound crazy but how about measuring how much you drain out and then use 1/2 the amount in coolant & 1/2 distilled water , I'm not trying to sound like a smart ** but that's what I'd do. Best of luck Matthyj

Originally Posted by 34_40

If the old stuff is red, you'll need to match that color or do a total flush a couple times. Any of the name brands are good. If you have aluminum parts (such as a intake manifold) make sure you read the bottle to verify it's compatible and will protect it.

Thanks, I appreciate your time.

Originally Posted by Matthyj

Might sound crazy but how about measuring how much you drain out and then use 1/2 the amount in coolant & 1/2 distilled water , I'm not trying to sound like a smart ** but that's what I'd do. Best of luck Matthyj

I was wanting to purchase the antifreeze before I drained it.

And I thought most coolant these days was premixed?


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In my area, we can still buy concentrate. If you go to a "big box store" like autozone or pep boys etc., they have the premix primarily.. at least up my way.

I save about 40% buying one gallon of pure coolant vs two of premixed.

Originally Posted by rspears

I save about 40% buying one gallon of pure coolant vs two of premixed.

Good to know. I'll look into it. Thanks.

OK, so I drained the coolant. It was surprisingly clean. But I had already purchased a Prestone "flush product" so I decided to use it before I put new coolant in. I changed the upper radiator hose from the universal accordion hose to the preformed hose that I got a part number for on this forum (thanks!), and installed a new thermostat. I was surprised that there was a thermostat already in the engine and it was indeed closed, not stuck open. After sealing the system back up and filling with distilled water and the "flush" product, I took it for an extended drive. After about a half hour of driving and several full throttle runs, the temp was still showing only about 140-150 degrees. Same as before. So I'd have to assume the old thermostat was working, and the new thermostat is working and the 140 degree reading is false.

So what's wrong? Bad sending unit or temp gauge?

This car has what I consider to be cheesy Dolphin gauges. They are on my list of changes, but it would be simpler and cheaper to just do the sending unit now.

Thoughts?

Thanks...


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Where is the sending unit located?

Originally Posted by Henry Rifle

Where is the sending unit located?

Top front intake manifold.

That's where mine is located, and it reads a solid 180 with a 180 thermostat. I'd suspect the gauge before the sender. It's possible to verify a sender by reading the resistance of the sender (with an ohm meter) - if you can find the temp vs. resistance curve.

Get somebody to check the temp with an infra-red temperature gun just to see how accurate you guage is.

Seems to me, before you could verify sending unit (by measuring resistance) you would first need to verify temperature. So the afore mentioned heat gun is a good start.

Once you know the actual operating temperature, you could then test resistance of the sending unit to know which is bad, the sender or the guage.