Alternator leaking coolant? I am not familiar with the 4.4 but alternators usually don't have any fluid running through it (anyone feel free to educate me if I am wrong). Depending on where the alternator is located, I suggest looking at coolant hoses that are above the alternator and make sure it's not leaking from there. Also have checked you coolant level lately? You may already know this but the expansion tank is known for having a hair line crack and leaking coolant which could drip on the alternator.

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2001 BMW X5 3.0 Sold
2008 VW jetta S
2006 Lexus Rx400h