Cooling System

In this article, we shall tell you how to maintain a classic cooling system in classic cars. The main thing that you need to know is that for the large part of the 1940’s cars and the later cars, the cooling systems are pretty good, but unless you are putting in a bigger engine, or adding air conditioning to a car that previously didn’t have it, your stock system should ideally serve you well. But it might be the case that the cooling system of your classic car isn’t performing as well as it should, even after 50 years, so we tell you how to maintain a classic cooling system.

First of all, you need to think about the radiator. The radiators from that time were designed for low, or no pressure radiator caps, and straight (preferably distilled) water, with a rust inhibitor for all times except winter. But don’t make the mistake of running coolant on a system intended for straight water – it’ll run hotter! Some people recommend a 50-50 coolant-to-water combination, with a high pressure radiator cap. The coolant would prevent corrosion in aluminum blocks, and would raise the boiling point of the coolant, in any high pressure system.

Now think about the leaks in classic cars. Sometimes, if you have a radiator rebuilt, the shop would detach its tanks, hot-tank it to clean it, rod out the core to remove the scale, and then solder up the leaks. However, you should know that this is only a temporary situation. The stuff would clog the tubes, and you would probably be let down at the worst moment possible.

Let’s talk about clogs now – sometimes it might be the case that you have a problem of overheating, and you think it’s a clogged radiator, so you fill the system and run the engine till the thermostat opens. You know when it’s open because the water in the upper radiator tank start moving – you can see this through the filler neck. But you know you have a faulty thermostat if the water doesn’t start moving. So here’s what you do next – feel carefully the front of the radiator with your hand. It should be cooler at the bottom and hot at the top – there should be no cold spots anywhere. You know your radiator is clogged, if you find cold spots. So ideally, back-flush it, and then test it again.

Now about back-flushing – ideally you could remove the radiator for this operation, drain it, disconnect the hoses, unbolt it from the frame, and lift it out. Then wrap rags around the end of your garden hose to stifle the leaks, and insert it into the lower opening on the radiator. Turn the water on full blast. Since you are reversing the normal flow of water through the radiator, you would get behind the scale and rust, break it loose, and force it out. Until the water becomes clear, keep flushing. However, before re-installing the radiator, back-flush the cooling system too. Do you want to avoid a mess? Then attach a radiator hose to the water pump inlet to direct the rust and discharged water down and under the vehicle. The thermostat housing should be removed, then take out the thermostat, replace the thermostat housing, and then put it in the rag-wrapped hose in the thermostat housing, and force the water back through the engine and the water pump. Similarly, keep doing this till the water becomes clear.

Now we shall tell you how to maintain a classic cooling system of classic cars. If you see damage and corrosion on the lower end of the tank, the classic radiator needs to be replaced. You should check the coolant – if it’s rusty, back-flush the system. The radiator cap should ideally be changed every 2 years. Don’t install a cap with pressure rating of more than original. You could blow out the water pump seal if you do.

The old side valve engines don’t cool so well anymore, but if you keep the system clean and drive the car well, it will be fine, don’t worry. The thermostat of classic carsshould be changed every 2 years, and make sure you install it facing the right way.