Car Problem Reports

Mercury Mountaineer Coolant Leak/Overheating Due to Radiator Leak

Mercury Mountaineer Problem
10 Reports
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Model Years Affected: 2003, 2006

Engines Affected: 4.0L V6, 4.6L V8

Average Mileage: 104,077 mi (72,350 mi - 144,000 mi)


A coolant leak may develop from the radiator. Ford has released and updated radiator and powertrain control module (PCM) software update to address this issue. The software update includes revised cooling fan operating parameters. Failure to complete both service procedures may result in repeated radiator failures.

  • Visitor, , 4.0L V6, 144,000 mi

    I am now on my 3rd radiator for this vehicle. The first radiator failed within 4 yrs of the car's life and the second 3 yrs later. Each time I had to replace the radiator. I did not go to the dealership because they wanted close to $1000 to replace the radiator.

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  • randy9110, , 4.6L V8, 91,273 mi

    Having radiator replaced tomorrow

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  • Visitor, , 4.0L V6, 120,000 mi

    Haven't fixed it, just found out.

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  • Visitor, , 4.6L V8, 101,000 mi

    I am working on my 3rd radiator........

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  • Visitor, , 4.6L V8, 77,000 mi

    My radiator is leaking from the seam too so I have been investigating this problem to some level of detail.

    Firestone checked the problem (for a fee) and was told by the OEM provider of the new radiator about a Service Bulletin on the problem. The service bulletin ONLY lists the 4.0L engine but the OEM insisted that it applies to the 4.6L too. Paid money (again!) to my local Ford dealer who I thought would find the problem and the bulletin and hopefully repair it under warranty or some other provision. Bottom line ... the Ford dealer shows no record of the 4.6L having this problem and is confused by what the OEM is saying. Firestone trusts this OEM who insists that the problem is well known and reprogramming is required. Too bad ... who to believe?

    I just paid Firestone to do the repairs ... need my car. Told Firestone to flash the computer with the upgrade if it showed necessary. Why take the risk?

    But very disappointed in Ford to be honest. This appears to be a well-known problem (OEM said it popped right up on his computer when the part number was entered) that is fixed by a software upgrade to what sounds like an initial design flaw. But Ford disavows any knowledge of the problem for the 4.6L. Ogden Lincoln Mercury in Westmont, IL is the dealer by the way.

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  • Visitor, , 4.0L V6, 97,000 mi

    Antifreeze leak at lower left (driver side)bottom of fin tubes. I had replaced the radiator with a new radiator from NAPA. Need to have Ford re-program the PCM with a new fan strategy. Check Ford's TSB09-8-1.

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  • Visitor, , 4.6L V8, 72,350 mi

    Radiator just started leaking like crazy. Dealer said there was a "crack in the seam". No mention made of the PCM update. Had to replace the radiator.

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