4.7 L heads
I have a 2004 GC with a 4.7L engine and have owned since new. The jeep has 120K miles. About 4 months ago, I had an exhaust manifold leak on the drivers side. The leak was repaired by a local shop. Since then, I have started loosing anti-freeze a little bit at a time. When the car was driven 70+ mph, the anti-freeze leakage was much greater. Now the leakage is greater all of the time with rough running and an engine code that states a problem with the #3 cylinder. I am told that it is the heads and a new engine is required or rebuiding the existing engine. I am told head gaskets are not replaced and the heads are not replaced due to this will cause problems in the lower half of the motor due to higher compressions. I have never heard of this in the past.