I had to replace the alternator on my Toyota Tacoma V6 4L and I noticed an ungodly amount of gunk collected on and around the old one. The truck is 2007 with just over 100K mi on it. The old alternator had literally 1/2" of greasy, muddy, black gunk over it but also on other pulleys around that area (tensioner, idlers, AC pump etc.).

Is this something normal for a truck this old or is it a sign of some problem? Should the front part of under the hood (so the radiator and the serpentine belt hang-ons) be taken apart every once in a while and cleaned to prevent this?

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    Could you provide us with some photo? It could be interesting to see how bad it looks, to be honest, it´s good to clean also under hood sometimes (especially when you drive off road or in dusty conditions). Oil+grease+dust can create this substance on everything, I am using Arva to clean underhood parts, but I am not sure if you can get this, it´s kind of heavy duty grease cleaner (list of ARVA ingredients), but you shouldbe able to find something similar.
    – Mustafa105
    Apr 8, 2014 at 8:44

1 Answer 1


More than likely the problem is a leaky valve cover gasket. It's just something which happens over time. The old one becomes hard and cracks, thus oil starts dripping. Over time, this collects on the different parts with whatever amount of dirt is available and, voila! You have gunk all over the place.

First thing to do is thoroughly clean the affected area with heavy duty degreasing agent and plenty of elbow grease. Whatever you can chisel off with a putty knife before you start with the degreaser. This will save you a lot of cleaning and make less of a mess.

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