Ford 5.0 engines in the trucks and Bronkos mainly during the 9X’s had a unique problem that would a lot of times get diagnosed as a leaking head gasket or warped heads. The problem was the PCV (Positive Crankcase Ventilation) valve would get plugged up or more often the vacuum port that it was connected to would become blocked by deposits of carbon and oil sludge. What you would find when you changed the oil is a brown foamy mixture on the inside of the oil cap. You may even see water drops in the cap. Now every mechanic out there knows this is most likely just a plugged port but it is quite often reported to the customer that they have a leaking or blown head gasket or a warped head. The reason is simple it costs about $45.00 labor to clean the port and depending on the cleaner used $10 to $40 for supplies. Now head gasket jobs go for around $1500.00 to $2500.00 shop dependent.
There are two ways to tell if you have a serious problem or just a dirty engine. If you have the same brown foam in the over flow bottle or on the inside of the radiator cap then I am sorry but you do have a serious problem. The second way is to ask to have your engine block checked. This is done using a solution that changes color from Blue to Yellow if there are any combustion gases found in the coolant system. The mechanic will let the engine cool totally and then remove the radiator cap and drain enough anti-freeze from the system to prevent contamination of the test. He or she will then start the engine and place the block tester in the place of the radiator cap. As the engine warms up samples of the air in the coolant system will be taken and as long as the fluid in the tester stays blue you have no problem between the cylinder and the coolant system.
Now remember that I already said that if you had oil in your coolant your engine had serious problems so that is a primary check. Just remember that water under the Ford 5.0 oil cap especially clear water does not mean major problems. It needs to be checked further to save you from a very costly and unnecessary repair.
