VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Need radiator advice?

When I fill my radiator in my 28 Chevy and drive around for 20 minutes or so the radiator over flow starts releasing lots of water so by the time I stop the radiator is at least a gallon or more low and when I shut it off I can hear the radiator seathing and creaking like it's to hot? The moto-meter is usually near the boil point but hasn't boiled over yet but I haven't gone any real distance yet ( maybe several blocks)for fear it might overheat?Any suggestions?

Hi Entsminger,
You might want to double-check your motometer against a candy thermometer in a pot of increasingly hot water. I have bought two of the darned things and neither one is very accurate. Your car may be overheating. Have you checked your thermostat?

-R

I haven't checked the thermostat ? Would that make water vent from the overflow tube if it was overheating or could there be another reason it might squirt a gallon or more from the overflow tube? Maybe I should remove the thermostat to see if that helps? It's a new moto-meter.

Hi entsminger,

You didn't give us any history about your '28. Is the overheating a new problem or a recurring one?

Many things contribute to the overheating of car engines. The more obvious such as bad radiators, ect. Timing is a great contributor to overheating as is too rich or too lean carburation.

Give us some history of the problem and we will post more guesses as to the problem.

Check your water pump seal as I had a lot of problems with the system sucking in air and then blowing water past the seal and through the overflow tube, etc. This happened even on test runs around town.

Well I've only had the 28 chevy for a few months and I don't know the history of it but it seems to run good, drives ok with what I would think is ample power. The engine appears to be in good shape. I took out the thermostat and it still leaks out a bunch of water ( after I fill it) from the overflow tube after it gets hot. It's never steamed over but I'm trying to prevent that from happening.
Let me pose this question? Since this car doesn't have a relief radiator cap like modern cars, how does this type of arrangment handle the preassure once the engine heats up? My only guess is that some water is pushed out the overflow tube till it gets to a certain level in the radiator and then only air is pushed out?? I was told the water should be visable when looking down in the radiator but is that true or does the radiator need some air space ,( maybe a few inches or a gallons worth of space)for heat expansion??

When dad started working on his 23 grainbox truck he slapped in a engine from the "way back shed". Two months later when in our towns Rose parade (no not that one) the old 23 boiled BIG TIME. Mouse in the house
dads28

After I fill the radiator to the top on the 28 and drive it around for 20 or 30 minutes it overflows a little (50% distilled water and 50% Zerex) and you can reach the fluid level with an index finger after is sits for a while, I have short fingers. Then after driveing some more it only weeps a little coolant out the WP bushing when it cools ( about a table spoonful) and the motormeter shows a midrange red line mixture, I don't have a telescope to read the temp.

I agree with Ray, sounds more like timing BUT when you fill the radiator leave about 1" down from the top to allow for the expansion. Put the thermostat back in after you check it (boil some water on the stove and make sure it opens and then closes when cool) If you are dead sure the timing is right remove the lower radiator hose hold your hand over the hose and fill the radiator it should all run out very quickly and the water tower should reach approximately about a 1/3 of the height of the radiator (to confirm if radiator has a blockage) failing that knock out the rear welsh plug and see how choked up it is this could also be contributing to your overheating problems.

Does the 1928 chev radiator bubble or make noise while running?
My 1915 will over flow when filled to close to top. That is by design.
You don't have a pressuized system. Does a compression gasket leak force out water?
Rex

Well I took out the thermostat and drove it arounfd today . The radiator was already somewhat low from the day before . The motometer didn't go into the danger zone. When I shut it off alot of water squirted out of the overflow tube? Now I'm sure the radiator is at least 2 gallons low? Did it get to hot? I don't know? Does the moto-meter register right when the water level is low?
So far the best advice I've got is check the timing, check for leaky water pump or plugged radiator. Any other things that might make water flow from overflow tube?

Hi entsminger,

If I understand your situation correctly the car gets hot very quickly even though you have not operated it in a stressful manner. That leads me to believe you may have a blown headgasket or a cracked head/valve seat. I suggest you fill the radiator fully, right up to the top. Don't put your face directly over the radiator filler, but watch as the engine is started. If you see bubbles or major movement of the water I would go to a radiator shop and ask them to perform a test to see if this is a headgasket or break problem. If negative, a big sigh of relief and on to checking other causes of overheating.

I HAD THE SAME PROBLEM WITH MY 32 AT FIRST, HEATING UP, WATER BOILING OUT THE TOP. THOUGHT ALL KINDS OF DIFFERENT THINGS WERE WRONG. WHEN ALL WAS SAID AND DONE, COME TO FIND OUT THAT THE TIMING WAS TO RETARDED AND THE ENGINE WOULD HEAT UP QUICKLY AND BOIL THE WATER OUT THE RADIATOR. YOU MAY TRY ADVANCING YOUR TIMING A LITTLE MORE AND SO HOW IT REACTS. IT SURE SOLVED MY PROBLEM. GOOD LUCK :) :) :) :)

Hello,
I am also having radiator trouble. I have a 26 coupe. The engin is restored and runs great but it overheats quickly. There are no bubbles in the water, it just gets hot after 10 minutes. Does anyone know what the running temp should be? We think there is a block in the core. There are cool spots in it so we know the location of the blocks. Radiator repair shops are scared of this thing because they do not think they can fix it. Does anyone know where to get a new core or functioning radiator?
Thanks,
Mark in Baltimore

Hi kavic,

I assume you wish to keep the car original. If so, you need to contact the Filling Station 1-800-841-6622 and purchase a new honeycomb core. I have installed several of them and can report complete satisfaction.

The other option is a modern core. Just depends on your objectives.

Many years ago I had a 27 that was doing similar things. After many months of testing/changing things around/cleaning etc. I came to the conclusion that the radiator was partly blocked.

What happens is that the water pump pumps X amount of water and only 50%X can fit through the radiator, the rest disappears through the overflow pipe. All sound familiar so far.

An old guy told me (gee I've learnt a lot speaking to old guys) to put a resrictor in the top radiator hose to slow down the flow into the radiator, guess what? it worked.

Maybe worth a try, also carry the the flow test as Ozjim suggested, this will tell you whether your radiator is any good.

But remember that whilst your engine is running the fan or air flow cools the water in the radiator. When you turn your engine off the water heats up slightly and therefore expands. If you run the water level to about half way up your inlet pipe, it gives the water room to expand without overflow, if you run the level any higher, then it expands to above the overflow and you lose it.

Another point to rember is the fan blade. A lot of Aussies run a 4 blade fan hoping to keep the water cooler. (It gets pretty hot in summer down here, often over 100 degrees).
In fact a 4 blade makes it worse as it puts extra load on the engine and makes it work harder. When I was involved with race engines we got about 8% increase in horsepower by taking off the fan. The 4 blade fan is great for parades, but after about 8 mph the fan ceases to affect the cooloing and the airflow through the radiator takes over.

Chris

Hi chris,

Now do you see why Chevrolet installed a single blade fan, to include the 28s, in the cars and only put the 4 blade fan on the trucks?

There is some truth to the restrictor in the upper hose, however for better operation, find and fix the problem.

Make sure you are using a thermostat & make sure it is the right temperature.

The 1928 is the only 4-cylinder car to use a thermostat.

Well guys, gidday to you all. Just returned from the VVCAA (Aust) 35th Anniversary Rally. I had to fit another radiator cause the original sprung an unfixable leak. I had some of the problems mentioned above, but I managed to get a solid 1 hour of driving before it overheated, due to lack of water, which I guess disappeared out the overflow.
I was talking to Ozjim ( a real wizz on 28's) the other day and told him I might put a restrictor in. He asked me whether I had a thermostat, answer no!
Jim reckons that a thermostat acts as a restictor and should fix the problem.
I'll get around to this and post the results
Chris

Overheating…… been there, done that….. I have a ’28 LO truck and had a major problem with over heating. I did the normal things like checked the timing, rebuild the carburetor and water pump (make sure that you use a baffle plate or that the pump has a baffle plate) and even cleaned out the radiator.

When all else failed I even bought one of those new fancy radiators that The Filling Station sells… it really looks great but nothing worked.

I also tried using a thermostat and even tried the restictor in the radiator line.

The last thing that I did was to replace the distributor. Somehow the unit looked good and my truck always started fine, but after a very short while the truck would over heat. I replaced the distributor and all of my problems went away. I have been on a few long drives on warm days and the truck stays within normal operating temperatures. Not sure if this will fix your problem but it did mine

Thanks Oman, I'll give it a go, seeing as I have a reconditioned distributor sitting on the shelf
Chris

chevgruoo downunder,This is off subject but how did your 35th Annivarsary Tour go????Were there many from the US there this time???Our local friend Sondra went and I know the Halfords are spending some time downunder,Wish I could make the trip but the oldies just can make it that far.