Engine overheats when A/C is on

2005 FORD EXPLORER
100,000 MILES • 4.6L • V8 • 2WD • AUTOMATIC
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DAVE BIESENBACH
  • MEMBER
  • 1 POST
Okay, i have turn wrenches for along time so. short version; car overheats when A/C is on driving or sitting if i turn on heater bring temperature back down. just installed 2 radiators first one leaked GRRR, new thermostat, new water pump, new clutch fan and and new fan blade had a chip .3 gallons of Napa 50/50 anti freeze . ran car with pressure cap loose was worse .
Jul 26, 2020 at 9:54 AM
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KASEKENNY
  • ✓Experienced Mechanic
  • 18,907 POSTS
There are a number of reasons this could happen. Clearly what you have covered would be the first and foremost of concern. However, since you addressed them the next items are actually part of the A/C system. We need to start with checking the pressures of the system. This may point to the issue or give us a better idea where to go next.

What happens most of the time with the compressor is it is actually locking up and adds that additional load to the engine and it causes it to overheat.

Here is a guide that will help with this but let's start with what the pressures are in the system and then evac and recharge it just to make sure it is properly charged. Then retest the system.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system
Jul 26, 2020 at 10:49 AM
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