what is the usual cause of overheating? I drove my 24 roadster a few miles yesterday, and it started steaming at the bottom, any ideas?
Steaming from the bottom sounds like it could just be that the radiator was overfilled and the hot fluid is coming out of the overflow pipe. The other reason is not good if the radiator is clogged or has a pin hole in the lower section or if the fins are coming detached from the tubes. need more information and maybe pictures.
Sounds like a leak to me. I'm not a fan of pouring stop leak products I to the rad but, Model T rads are expensive so I usually try that method first. I've had very good luck all my life with Gunk brand stop leak or any powdered aluminum type and no luck at all with Bars Leak pellets. Might as well try that first before you trash an otherwise good rad.
Overheating is when the overflow tube starts pushing out large volumes of water, and the car loses power.
Steaming from the overflow tube is not overheating, it is normal for a bit of steam to come out for a minute or two after stopping.
Overheating can be caused by:
A plugged / internally corroded engine or radiator.
It can be caused by improperly set timing.
It can be caused by lean mixture.
It can be caused by worn engine components.
It can be caused by bands adjusted too tight.
It can be caused by parking brake adjusted too tight.
Then theres the 30 cent fix
"it started steaming at the bottom"
It sounds like you mean it's coming out the overflow tube?
How much water and/or "coolant" is in the radiator? It should be at least an inch or so over the top of the tubes, but not right to the top. If it's not over the tubes it won't circulate w/out a water pump.
If it's filled right to the top when cold it will expand when hot and spit out the excess through the overflow tube.
A little steam coming out the bottom of the overflow tube on a hot engine is normal.
The coolant should be at about the level of the Ford emblem which is pressed into the front of the radiator. If it is higher, the water will expand and go out the overflow pipe which is on the left (as you sit in the car)side. If the fluid was too high and steam comes out that pipe, it is perfectly normal and will stop when the coolant reaches its own normal level.
Other causes are as posted above, a small hole in the radiator, tubes separated from fins, or clogged radiator. A clogged radiator or small leak can be corrected by a good radiator shop. Be sure to check with local club members for a shop familiar with brass radiators, especially old ones such as Model T.
Still other causes can be too lean fuel mixture, or retarded spark.
On a very hot day it could get hot after pulling a steep grade and then stopping such as for a signal. You need a working fan if it idles for long periods, such as a 5 minute signal or slow traffic. When going along at a reasonable speed, the air blowing in from the front of the car should be enough to keep it cool.
Last resort, but a very good one, is to buy, about $1,000 a new radiator.
How hard did steam come out of the overflow tube? Be more specific about everything that occurred.
A bit of water and/or some wisps of steam can be normal. Steam that blows out with force, and can even be heard hissing out, is not normal.
The possible causes are listed above.
Most new, inexperienced Model T owners make the mistake of filling the radiator all the way to the top of the fill neck. The T will only use what it needs and will spew any excess it does not need out the overflow pipe once the car reaches operating temperature. The correct level is about even with the inlet hose connection where it enters the radiator. Jim Patrick
PS. After you stop your car and the radiator dries off, check the front and back of your radiator for wet spots or wet streams running down. A leak would be located at the top of the stream. Also, check your hoses for leaks and clamps for tightness, as well as the steel inlet pipe for rust through leaks. If you have a petcock on the bottom of your radiator, make sure it is fully closed.