Condensation Under Coil Cover

[Ross]

Well, since I recently got my new 4.10's, I thought I would treat my MM to a new set of plugs. Didn't really think they were necessary, but I wanted to try something different. Never had any Bosch plugs, so I thought I'd try them out.
Took off the coil covers and my passenger side cover had a lot of condensation under it. When I took out my plugs, the two back plugs were very rusty where the condensation had apparently run down into the holes on top of the plugs. Tried to be careful not to knock any chunks of rust down into the engine with the plug out, but I'm certain that a little must have fallen in.
WTF? Driver's side was clean and dry.
Any clues as to what the problem is? Engine has been running OK, no obvious signs of anything wrong.
BTW: Let this be a lesson to all of us. Even though these engines are designed not to need new plugs for a zillion miles, it's good to take some things apart every now and then just to see if there's anything fishy going on.

[carfixer]

Ross, be sure the rubber gasket for the coil cover is in good shape and is in the groove all the way around the cover. Apply some silicone sealer around the wire harness where it goes through the opening in the cover. This will seal out any water from getting in.

We had a Navigator come in with an engine miss. We found the coil cover gasket on the right cylinder head was completly missing. It had filled the spark plug wells up with water. One of the coils were shorted out. The plugs were rusted so badly, one broke off as soon as we put a socket on it. Head had to come off.

Glad you didn't wait for 100K miles to check yours!

[fastblackmerc]

Ross, be sure the rubber gasket for the coil cover is in good shape and is in the groove all the way around the cover. Apply some silicone sealer around the wire harness where it goes through the opening in the cover. This will seal out any water from getting in.

We had a Navigator come in with an engine miss. We found the coil cover gasket on the right cylinder head was completly missing. It had filled the spark plug wells up with water. One of the coils were shorted out. The plugs were rusted so badly, one broke off as soon as we put a socket on it. Head had to come off.

Glad you didn't wait for 100K miles to check yours!
What he ^^^ said. Just a little dab of silicone on the harness works really good.

[SergntMac]

Typical side effect of assembly line/mass produced components. Slap it together and let the owner work out problems with the dealer.

I've seen this on 3 MMs now, one was the driver's side #5/6 cylinders. The problem is that the gasket is not properly seated in the coil cover and it gets mashed and twisted during the build. Thus water/ moisture seeps into the well and rots the sparkplug boot too, resulting in rough idle and an engine miss at cruise speed.

My advice for all, is to open it up both sides, check and/or reseat the gaskets correctly and restore the seal. As stated above, also check the seal at the rear of the cover. This too, has to be installed correctly, or, it leaks.

[Marauderjack]

Mine has had water in number 3 & 4 holes:argue: I tried the silicone thing but it wouldn't stick to the gasket??:confused:

I think mine came from washing the engine and not everyday rain.....I check it regularly now!!:beer:

Marauderjack:D

[Ross]

I was also concerned that the moisture maybe came from washing the engine, but I'm always careful to use very low pressure water. Still, even under low pressure I guess water could get under there if the seal wasn't fitting properly. The thing is, I haven't washed my engine for a couple of months. You'd think that any water in there would have evaporated by now due to the engine heat.
I guess the condensation just comes from the high humidity down here, coupled with the heating/cooling of the engine, and a bad fitting seal?