The vehicle is a 2011 L322 full size with the NA 5.0 engine. It's got around 80k miles on the clock. I've got it all stripped down and the right head removed to replace the head gasket. I'm looking for some thoughts about what I should replace while it's all apart as it's many hours of work to get down to the basic engine long block to do this work. The source of the head gasket problem appears to have been water loss from leaks at the plastic water "manifolds" at the front and rear of the intake manifold. These water manifolds are both assembled of two plastic pieces that are solvent or heat welded together, and they both show signs of leaking at the joint, particularly the piece at the front of the engine. So these water distribution pieces are going to be replaced with new ones, and here are some of my other thoughts:
- Replace the head gaskets on both heads, even though only the right head had the leak.
- Replace the timing chain tensioners with the latest version upgraded tensioners, and replace the plastic ramps.
- Put a new water pump and thermostat on it. Put all new water hoses on.
- Have the injectors ultrasonically cleaned and install with new teflon seals.
- New spark plugs.
- Replace the heated oxygen sensor in the right exhaust manifold. The other O2 sensors look to be replaceable from the bottom.