Hey I have an 04 f150 with the 5.4 I drive for an hour everyday to work but after the drive I have an excess amount of condensation build up under the oil cap and my dipstick is rusted I'm just wondering why so much build up and how can I fix it

 

My first thought is your PCV needs to be replaced.

 

Ok guys so my truck is 5.4 and I'm getting excessive milky oil under the fill cap I'm not losing coolant and I checked out my pcv valve and it tested fine I'm fairly new to mechanics and am stumped any suggestions

 

If you think you're stumped, I'm right next to you . How did you manage to test it if it has a calibrated spring. Your best bet is to just replace it with a new one from Ford. When cold air gets into the engine the moisture in it condenses on the inside of the valve covers and fill tube. I would make sure the oil fill cap is not allowing cold air to get sucked into the engine. Those 5.4s are pretty fussy about the oil you feed it. Use only what the manufacturer recommends. Many 5.4s have bit the dust due to the incorrect oil being used in them. I realize your vehicle is 10 years old and you must be doing something right or you would have had bigger problems.

 

I understand the pcv has a calibrated spring from what I understand about it the spring isn't the main fail point but the element that heats the air before it goes to the engine. So I followed fords pinpoint test to determine if it was working properly. Also if the spring was not allowing the crankcase to vent would it not blow a seal or leak at a weaker point? My oil fill cap is a tight fit I too thought it might be the cap allowing cold air past so I took some fresh oil and put it all around the cap and no oil was sucked in. This is why I'm stumped

 

If the engine has a vacuum leak that the computer is able to compensate for you would not notice anything unusual. One way you can check this out is get the fuel trim numbers and that will tell you if the PCM is covering up a different problem.

 

it could be from the humidity in the air while driving to and from the job, may sound really stupid but the air filter doesn't stop the vapor going through it and when it mixes with the temp of the engine it condenses up under the valve covers making appear milky