This site has provided some great answers so I am hoping someone can help. I have researched this on the forum and have not found anything related.

I have a 2010 F-150 XLT, and I have been having AC issues for the better part of the summer. I noticed that the AC was not cooling, so I had the system charged by a shop. Within a week the AC system blew off and has blown off a additional times post being charged by shops. None of the shops can find a leak or issues with the system when they have it.

However after each time it has been charged, it will blow off within a week. One shop started to go down the road that the fans were not turning on (bad relay), causing the system to over pressurize, because it was getting to hot.

Before I can take it in to a dealer and get raked over the coals, I wanted to try and have an idea what the issue may be.

Thanks in advance!

 

By blowing off I assume you mean at the pressure relief valve on the compressor. If this is the case could be due plugged expansion valve, debris or bent fins on condenser, restricted air flow through through condenser, refrigerant over charge, to much oil in system, wrong refrigerant or possibly a bad blow off safety valve.

 

Those fans not only cool the trucks engine via the radiator, but they also cool the a/c condenser and is a primary cause for your symptoms. Once you get the fans working, provided everything else is ok with the a/c that should be all you need.

I find it hard to believe the shop couldn't figure that out, one thing I will say, NEVER go back to them if they cant do a simple a/c diagnostic.
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