* Incorrectly routed hoses: The coolant hoses might be connected incorrectly, causing poor circulation and leading to overheating. The AC system also relies on a specific routing of hoses. A misrouted hose could restrict refrigerant flow, preventing the AC from working. This is a very common problem after engine swaps.
* Air in the cooling system: After an engine swap, air pockets can easily get trapped in the cooling system. This severely impairs cooling efficiency and can lead to overheating. The system needs to be properly bled of air.
* Faulty water pump: The water pump, which circulates coolant, might be malfunctioning or installed incorrectly. This would cause overheating.
* Faulty fan clutch or electric cooling fan: These components are crucial for cooling. If the fan isn't engaging properly, the engine will overheat. This is especially important when the AC is running, as the AC condenser adds heat to the radiator.
* AC system issues related to the swap: The AC compressor, condenser, or evaporator might have been damaged during the swap, or the lines might have been improperly reconnected or charged. A leak in the system is also a possibility. It's important to note that the AC system often operates at high pressure, making damage during the swap a distinct possibility.
* Timing issues: If the timing belt or chain was installed incorrectly during the engine swap, it can cause various problems, including overheating. A slightly off timing can affect the engine's efficiency and ability to regulate its temperature.
* Low coolant level: This seems obvious, but it's important to double-check.
What to do next:
1. Go back to the mechanic who did the engine swap: Explain the problems and strongly suggest they re-check all the items above. Since they performed the swap, they should be held accountable for any issues stemming from their work.
2. Find a different, reputable mechanic: If the original mechanic is unhelpful or dismissive, seek a second opinion from a different shop specializing in your car's make and model. They might catch something the first mechanic missed.
3. Thorough visual inspection: Before taking your car anywhere, inspect the coolant hoses and all cooling system components for visible signs of damage or misrouting. Also, check the coolant level.
The fact that both the AC and overheating issues started simultaneously after the engine swap strongly indicates the problems are related to the work performed. Don't give up until these issues are resolved. It's important to get this fixed to avoid further damage to your engine.
