Needing some major help! I have a 2008 Maxima with 129,000 miles. I replaced both camshaft position sensors which fixed the check engine and traction control system lights. However, I am now experiencing overheating issues. I have replaced the radiator and cap as there was bubbling in the coolant reservoir. The fan is turning on and I bought a new one just to check and it was working exactly the same so I took the new one back. I bought a water pump, thermostat, and non-related, a valve cover gasket as it has a small oil leak. I took it to the shop to have the parts put on and the technician claims there is too much pressure on the upper radiator hose and told me it was the head gasket. This has me confused because there is absolutely no coolant in the oil or oil in the coolant, and no smoke coming from the exhaust. Motor runs like an absolute champ. I really don't feel its the head gasket but maybe I am wrong. Can anyone help me figure this out please?

 

probably head gasket. oil and coolant mixing is very rare with MLS gaskets.

based on your diagnostic procedure for the cooling fans id be inclined to trust the professional. if you dont like his answer you can always go get a second opinion at another shop. or you could ask anyone with subaru experience to smell the cooling system. anyone who has done more than a a couple subaru head gaskets will know exactly what a blown head gasket smells like to the nose. they dont usually trigger combustion leak fluid but have a very distinct smell to them. also a 5 gas analyzer in the cooling system will very quickly pick up HC and CO in the cooling system that wont be present in a properly running engine.