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2007 FJ Cruiser-AC Blows Hot Air @ Engine Coolant Service

Home Forums Stay Dirty Lounge Service and Repair Questions Answered Here 2007 FJ Cruiser-AC Blows Hot Air @ Engine Coolant Service

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  • #992816
    Lisa PLisa P

      Toyota FJ Cruiser Base Model 2 wheel drive
      V6 (241Ci) 4.0L (1GR-FE), MFI
      Mileage: 100,800

      Hello All:

      Can the engine coolant system/fluid directly or indirectly affect AC performance? Or, can an engine coolant system service affect (good or bad) AC performance?


      3 weeks ago did some 100,000 mile maintenance on my FJ: Engine Coolant system service/fluid flush, Transmission Fluid Flush & replaced front/back shocks. After I got it back, my AC only blows cold air at night (60 degrees outside). And even at night after it’s been running a bit or on the freeway, it’s no where near as cold as it was before the service. During the day it’s worse (70 degrees outside). I can just barely feel cold air if I put my hand right next to vent & put the vents setting to blow only up top. Before the services I mentioned above, AC was blowing cold no matter how hot it was outside. It would even blow cold when idling, but blows very warm now when idling.

      I didn’t notice this problem till about 2 weeks later. After I got it back, had a cold spell outside & wasn’t using the AC. But had a couple warm days in a row this week, used the AC, & then realized the issue. However, it was very warm in the days leading up to the service so I had used the AC right before I took it in. (Live in So Cal by beach & in winter it can be 80 deg one day & 65 the next).

      When realized issue, called repair shop right away who did service. Was told the engine coolant service/fluid flush-replace has nothing directly or indirectly to do with the AC… that it was just a funny coincidence. So they want to charge me again ($152) to check AC/recharge it & add “freon” if it’s low. And more $$ if there’s a bigger issue (leak, etc).

      My Question(s):

      Is the repair shop being truthful that the AC problem is “purely coincidental” & has nothing to do with the engine coolant system and service they did?

      He also told me the “freon” for the AC is a separate fluid than the coolant for the engine. Is that correct?

      During the engine coolant service, could/should it have been discovered that the AC system had leaks?

      If AC “freon” is leaking, would there be a puddle under the FJ after it sat for a while?

      If I dont turn on AC, how long can I wait to get it fixed? I don’t have the money for repairs, so might be about a month before I can.

      Things I’ve Tried:
      Some experiments on the AC as described above (when it’s blowing all hot air, temp of day, changing vent settings, running the car on fwy, etc.) Nothing I try causes AC to blow at the cold temp like it did before service.

      Last thing I’m going to try is changing the cabin air filter… it’s due. I haven’t tried that yet before posting because don’t have the funds to buy one right now (was also going to try to change it myself). But if it was the cabin filter, I logically would have had this problem before the services?

      ***below is the engine coolant service portion of the repair that was completed:
      Coolant System Flushed with Extended Life Coolant
      -flush entire coolant system
      -check for any visual coolant leak
      -check drive belts & upper & lower hoses
      – test drive for proper coolant system temp.

      Thank you all in advance!

      FYI: I have no automotive repair experience – so am seeking advice on whether repair shop was truthful & then I can decide whether or not to take it back to them. I have only taken it in to them once before for spark plug replacement & had no problems.


      • This topic was modified 2 years, 5 months ago by Lisa PLisa P. Reason: punctuation
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    • Author
    • #992862
      Jonathan GabrielJonathan Gabriel

        Hi Lisa, You have a lot of questions and I think that I can help by narrowing it down to this. Yes, the coolant system and A/C system use different fluids, not to mention the A/C system has a secondary gas system which helps circulate the freon. The purpose of the coolant is to maintain the engine temperature at manufacturer spec. Now, during typical services, no one looks to see if an A/C system is leaking, why you may ask. Well because in order to accurately tell that it is leaking, they would need to use fancy equipment to measure the freon/gas levels in the A/C system OR insert a UV light activated detection liquid to the A/C system to see where the leak is happening IF any leak is even occurring. So thats just not something mechanics normally go out of their way to do, thats a service all on its own. To sum all of this up, if you suspect foul play, do not go back to this service station. Have the A/C system check by a shop that has the proper equipment to extract and refill the system. I think it would be fair to give the benefit of the doubt first before assuming anything. Also, the cabin air filter would not hinder cold air from being blown, it would affect air quality and even have a distinct bad odor when you turn on the cold/hot air. Hope this can point you in a better direction.

      Viewing 1 replies (of 1 total)
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