Close
Mercury Mountaineer Problems

Coolant Leak/Overheating Due to Radiator Leak on Mercury Mountaineer

Problem Description and Possible Solution

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.

(35 people reported this problem)

Mercury Mountaineer Vehicles With This Problem

RepairPal Fair Price Estimate
$420-$636
RepairPal Verified
Average mileage: 121,066 (13–220,000)
Engines affected: 4.0L V6, 4.6L V8, 5.0L V8
5 model years affected: 1998, 2002, 2003, 2006, more2007
Not Your Mercury Mountaineer Problem?
Brake problem? Or maybe a faulty head gasket cylinder?
Learn About Your Car Problems
Search For a Specific Car Problem
Viewing 1-19 of 19 comments
After replacing the radiator at a dealership, and putting on new hoses, the car still is overheating. I've been back to the dealership 4 separate times....they seen confused about what's causing the problem.
What should I ask them to try....reprogramnming the PCM ?
Appreciate any insight you could give me.
Radiator replaced October 2014 August 2015 new radiator started leaking same as other radiator at this time has not been repaired waiting to see to make sure I can get the problem fixed permanently this time
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.
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.
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.
This is ridiculous. I'm on my third radiator on this vehicle and I'm irate about it! The 3rd row seats stopped working and the dashboard lights go out and the horn just stopped working on day and the back rear whipper doesn't work anymore. WTF.
had a continual problem with leaking fluids never was really fixed I finally added stop leak which I had to do many times finally it blew my head gasket had to pay over $1600 to get engine repair & bought a new radiator nothing but continuos problems since I bought it in 2010 leaking etc even after that the hoses went TWICE to the radiator bad workmanship on this vechicle
Radiator constantly leaks. Had repair done. Worked for about 18,000 miles and I'm back where I started. Don't know what to do!
Yesterday I had the third new radiator installed in my Mountaineer. My dear brother found this service bulletin which I will take to the local Ford dealer. Just hoping the fix doesn't cost more than a fourth radiator.
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.