coolant in spark plug cavity

[supra1970]

2015 edge standard aspirated V6 with 18K miles coolant is leaking into the spark plug cavity (external to engine) causing a miss fire of # 5 cylinder.

Just started in the last 500 miles only warning was an misfire and check engine light that went on and then reset on it's own. Head casting porosity? dealer had it for 10 days still not repaired.

 

Any one hear about this problem

[WWWPerfA_ZN0W]

Hard to imagine where that leak is coming from without a seal issue. The location is pretty unusual. The closest coolant source is the crossover tube that runs underneath the lower intake manifold. The plug well is essentially sealed by the coil, so if there is coolant in the plug well, it has to be coming from a valve cover failure of some sort.

 

I HAVE heard of block porosity, but just don't see that causing an external issue like this one.

[macbwt]

Could be or cracked head. Trying to think how it could get in there through a gasket leak. Hair line fracture would allow coolant through. However this may be more than that since it gathers up enough coolant to cause a missfire. I would scope the cylinders to check for coolant the leaking cylinder would be essentially steam cleaned of any carbon deposits. Check oil also. Test the oil. If you have coolant in the oil then you will need major engine work.