Here's why:
* Material: Cylinder heads in those years were often made from cast iron, which is susceptible to cracking under extreme temperature changes. Overheating causes rapid expansion and contraction of the metal, putting stress on the head.
* Design: The 22R head has a relatively complex design with internal water passages. Coolant loss leads to localized overheating, putting extra stress on these passages, making them more prone to cracking.
* Pressure: Overheating can also lead to a build-up of pressure within the cooling system, further stressing the cylinder head.
Other potential points of failure:
* Head gasket: While less common, a blown head gasket can be a consequence of overheating and can also lead to coolant loss.
* Radiator: A damaged radiator can cause coolant loss, but it's less likely to crack due to overheating directly.
Important Note: It's crucial to address coolant loss promptly to prevent serious engine damage. If you suspect overheating, stop driving immediately to prevent further damage.
