just had an ignition coil go on the car at 91,xxx miles and noticed the front of the engine has a a lot of build up on it. Curious opinion and feedback if someone thinks I have a problem and should start searching the engine.
To me that looks like oil seepage from the valve cover. Can get kind of messy (follows the law of gravity), but if your oil level stays about the same between changes you could wait to replace the valve cover gasket.
On my 2014 there is a little seepage right near the right hand side by the water pump, but nowhere else. I would more than likely think it is a leak with the RTV that is used to seal the front cover.
You might just want to use a torque wrench and tighten down all the front cover bolts. The torque spec for those fasteners is really low, so I can see them allowing some seepage over time. Personally I am going to retorque mine in the next month or so. I have no "liquid" oil on the outside of the cover, just discoloration like it happened at some point.
I will say that it is quite disconcerting to hear that coils are going out with less than 100k miles and less than 6 years on the engine.
Normally on direct ignition systems the coils are just fine for 150k-200k miles AT LEAST. Just sad that things have gotten to where they are at in manufacturing. I mean age is usually the big issue for ignition coil systems. Even then I have coils from a 2001 Acura that operate like new still at 230k miles. I also have ignition coil pack from a 2002 Mustang that were bad with only 79k miles and a 1996 Explorer that had only 42k miles with a bad coil pack. All OEM coils for reference.
Makes me wonder if it wouldn't be worthwhile to just pickup a set of MSD aftermarket coils to put on my 2014. I have no ignition issues as it stands, but why wait if they are prone to fail.
I Have the same thing on my 15 CTS. This is not a leak as long as oil level is normal. A small spacing in the RTV. Not an issue! Clean the area and observe the frequency and intensity, mine is very minimal so mechanic told me just to ignore it.
I did buy a set of MSD coils. I ran the car before swapping them out, taking note of how it ran, accelerated, any noises, etc. I even felt the engine block itself and it had what I would consider to be a "regular amount" of engine vibration.
I let the car cool a bit and then put the MSD coils on. Started it up and immediately noticed how much smoother it was. I mean it was REALLY smooth. I took it for the same drive I did earlier, came back and did the same engine inspection while running. All I have to say is by feel of the engine block it was completely glass smooth, not even a hint of mechanical vibration. You still had the fuel pump noise at the back, and could hear the PCV valve doing it's thing, but as for vibration, none. I will also state that acceleration was completely smooth as well. Amazing difference, considering I thought it ran well prior.
For reference I changed plugs a few thousand miles prior to doing the coils.