VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 over heating

My 1928 Chevrolet fire truck over heated this weekend. When I arrived at my destination it unloaded a lot of coolant. It did this several times later in the day and the next. I kept adding water and it over heated and dumped the radiator fluid out. I think it came out of the over flow pipe. I tightened the packing nut, tightened the belt. Not being much of a mechanic I pulled the thermostat cover, to discover there wasn't one. I had a water pump installed about 6 years ago. I would appreciate any assistance. Also does anyone know the size of the packing for the pump?

I could really use some help. What could be the reason for it overheating? The fluid that came out of the radiator looked nice and clean, so I am assuming the radiator is good. Do I need to rebuild the water pump?

Well assuming it didn't overheat before this time, it could be:

A loose fan belt,
The baffle plate in the pump corroded though,
The head gasket leaking and pushing the coolant out,
Using too high a gear on long inclines which makes the fan turn too slowly,
Corrosion sludge blocking the water jacket behind no four cylinder,
Corrosion blocking the small holes at the back between head an block,
Rubber hose delaminating inside and reducing water flow,
Thermostat malfunctioning.
Are you sure it's not just overfilled and after a run heat build up after switching off makes coolant expand and overflow?

I'm sure there are other things that escape me for now but eliminating all the above will narrow things down a bit.

Good luck, let us know how what you find.

Bernard

Thanks, I will start the process of elimination.

When you say it is overheating is that because the you have a MotoMeter that is indicating that or is it that you see water discharging on arrival. Cars often run happily for a long time and then discharge on arrival simply because heat from the engine transfers to the water which then expands. You say "on arrival" so presumably you have travelled with no problems. Let's clarify that for now and see where it leads.

The cold coolant level should only just cover the radiator core. Any more will be expelled either during running or soon after the engine is shut off. All that heat generated when it is running has to somewhere and the coolant gets the majority. That additional heat expands the coolant and even more any trapped air or air bubbles in the engine. In most cases it is air bubbles getting larger with heat and less internal cooling passage pressure that push out the most coolant.

The moto meter is in the higher level but not all the way to the top. It expels radiator fluid after being driven for a half hour or so. When I stop it over flows. It has not done this in the 15 years I have owned it. Thanks.

It still might be the water pump packing. On my 29 if the pump can suck a few bubbles around the packing as it is pulling hard they get into the water and when they combine and expand with heat the radiator will overflow. Usually won't happen until the engine is turned off. The Filling Station sells packing for those pumps at a pretty reasonable price.

So it is running hot from start and after a while it basically boils. You say it has run fine for 15 years and this is a recent occurrence. Something has changed.Perhaps some maintenance needed. If it leaks anywhere it will run fine until the water drops and it starts to overheat, so check for leaks.The water pump can pull in air but when stationary it would tend to leak so if it doesn't leak it's most probably not pulling in air. Does the radiator need a flush or replacement? Did you put a thermostat in? That tends to slow down the flow so water spends more time in the radiator getting cooled. Checked your timing? Do a thorough service, plugs, points ,tappets etc so the engine is running efficiently. Do that and see what happens.

Are you seeing bubbles in the top radiator tank when the engine is running? If so it could be a blown cylinder head gasket, or worse still a cracked cylinder head.

franco

Thanks for your thoughts. Do you know the size of the packing?

The Moto Meter doesn't indicate it is running really hot when I am driving. It is on the bottom of the indicator for summer driving. Driving isn't a problem only recently when I stop it has released a lot of water. I believe it is coming from the over flow port. Thanks

Radiator overflowing on slowing or stopping the engine is a strong indication of air getting into the cooling system. Number 1 culprit is the water pump. Air will get past the packing on the shaft when no water will leak out. If there is a water leak you can be nearly 100% sure it is sucking in air. Those air bubbles expand with heat and even more with the pressure in the block from circulating water is reduced. That expanded space is the coolant pushed out the overflow.

What is the process of installing a new packing on the water pump?

My 1925 Superior K is experiencing a similar problem and I'm in the process of trouble shooting. If the concern is a blown head gasket there is a combustion gas detector kit to use on the radiator to check, it runs about $45

For adding some packing to what is already there, here's what AntiqueMechanic said about a 1928 water pump:


Cheers, Dean

I solved my problem on our '31 with 3/16 Teflon packing rop.

Hi all,

The other option is to think outside the square and fit modern water pump internals using a modified Chev 4 water pump housing, I did in 2009 and the benefits are

* No water use (using expansion tank)
* No water loss when engine turned off.
* Running Modern coolant
* I check water level about every 3 months.

Regards

Ray

before buying a test kit for exhaust gas, check with your local parts store, I know both Autozone and O'Reillys will loan you a tester and you only need to purchase the test fluid

I want to thank everyone for their responses. I tightened the pump packing and didn't over fill the radiator. I took it out last weekend and it ran very well. As for the packing issue. I don't like Teflon packing, it wears the shaft. I use a good pump packing pure graphite packing from either Garlock, Teadit or one of the major packing company's. It self lubricates and dissipates the heat. All the major refineries use this for their fire pumps. Thanks again for all your help!