Degrees of Damage
There are few things a driver can do to a vehicle’s engine that are more damaging than allowing it to overheat. From melting the oil cap to cracking the engine block, a wide spectrum of potential issues can arise as a result of an overheated engine.
After an engine overheats, there are several examinations that help determine how much damage may have been done.
Oil Cap
After the engine cools, twist off the oil cap and inspect it. If the cap is plastic and the plastic is melted, that could be a symptom of more issues. If the cap is metal, inspect the rubber seal inside. If the rubber is melted, that usually indicates the engine has even bigger issues from overheating.
Check the Oil and Antifreeze
If the oil is a tan or beige color and has a gummy consistency, that means there is a space between the head(s) and the engine block. When an engine overheats, it can warp the soft aluminum of the heads. Small waves are created along the surface of the heads where they rest on the block. Those waves create spaces and those spaces allow antifreeze to leak into the lubrication system.
Review the antifreeze. Through the same spaces between the heads and the engine block, oil can leak into the cooling system. Again, if there is a gummy substance that is light tan or beige colored, there is an issue on the threshold between the head(s) and the engine block.
Check for Bubbles
There are two types of bubbles that can appear on the surface when the radiator cap is removed and the engine is running – those from an air pocket in the cooling system line and those from engine problems.
When the bubbles are caused by an air pocket in the cooling system, the coolant fluid level will drop as the bubbles surface. However, if the coolant remains at the same level even though there are bubbles surfacing, it means the head gasket is blown, the heads are cracked or warped, or the engine block is cracked.
Major Issues Caused by Overheating
- Head gasket(s) blown.
- Head(s) cracked or warped.
- Engine block is cracked.
