Carbon buildup on the top of the piston is common. Over time this can lead to symptoms varying from light ticking to knocking noises. Performing a fuel injector cleaning procedure can often help the condition by removing some of the piston top deposits.
Engine Knocking Noise From Carbon Buildup on Chrysler Town & Country
Average mileage: 142,274 (128,000–167,000)
5 people reported this problem
2005 Chrysler Town & Country 167,000 mi, Visitor
The van ran hot and started making a knocking noise. The running hot issue was a thermostat sticking. We just replaced the thermostat. I do not know why it is knocking. We have tryed changing the oil, the oil filter, and an air screen. It hasn't helped
2001 Chrysler Town & Country 135,098 mi, Visitor
2002 Chrysler Town & Country 139,000 mi, Visitor
Loud knocking from tio end of engine when under load.