HunterFL772

Hello all, I have done a ton of reading and more or less understand that the 5.4l 3v does not have a PCV valve that you can replace and "doesnt need to be serviced". However, I removed the PCV hose on the driver's side of the engine and found it dripping with oil.

My truck burns oil like nobody's business and will die at idle. I have been just feeding it oil and riding it out. However, I believe a bad PCV system is to blame and is causing the truck to run rich. So how does one replace this PCV valve? Do i have to pull the valve cover and replace it?

Please help! Thanks, Hunter

techrep

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adrianjwalsh

Hello. This is an issue that I have thoroughly researched. I posted in this forum a not long ago asking for help in understanding the PCV system. I ended up getting a detailed explanation of how it works. The way that I understand it, the PCV system of the 5.4 3V works by connecting a hose between the valve cover and intake manifold, so that any crankcase pressure created by blow-by is immediately neutralized by the vacuum of the intake manifold. If the engine is burning oil through the PCV system, it is most likely because the engine is losing compression due to a problem with the piston rings. According to my research, there are two schools of thought. Some people believe that worn piston rings and cylinder walls are the only possible explanation for losing compression past the rings (blow-by). Others believe that hard carbon deposits can form around the piston rings, causing excessive blow-by.

FordTechMakuloco is a Ford mechanic that uploads videos to YouTube, and he has a very deep and thorough understanding of the 5.4. I emailed him regarding the oil burning issue, and he suggested that I try a product called BG 109. I've tried it a few times and it doesn't seem to have helped my oil burning issue. But regardless, there does seem to be some legitimacy to the carbon deposit theory.

Some members of this forum use a device called a catch can to reduce the amount of oil being sucked into the engine. But ultimately, oil consumption does seem to be a fairly prevalent issue with this engine. I believe I've covered about everything that I know about the issue, but please don't hesitate to ask for any clarification. Here is a link to the thread I created in March:

https://www.f150forum.com/f4/positiv...on-pcv-409981/

Mark Cameron

Hi
Have you carried out a cylinder leak test. This is different to a compression test. If so it will identify what cylinder or cylinders and blow by or may be non have it and it is something else. Either way if i were you i would get this done first to identify the exact problem.
A cylinder leak test is when you put a cylinder on top dead centre, remove the spark plug and fit an adaptor into the plug hole. This then connects to a machine that will put air pressure into the cylinder and the gauge on the machine will indicate how much leakage you have. You can then listen down the exhaust, intake pipe or oil filler cap to see were the leak is coming from. If the noise is from inlet then possible inlet valve area, exhaust pipe would be exhaust valve area and oil filler cap would be rings or bore. You carry this out on all cylinders and that will tell you what cylinder and what area of that cylinder has the problem
Hope this helps
Mark

HunterFL772

Thank you all for your input! I appreciate the help. No, I have not done a cylinder leak test, but I will look into that for sure.

To be clear, replacing the valve cover or the heated pcv unit wont solve my issue? The cylinder is for sure the source of the oil blow-by, but the pcv system should filter some of it out.

Again, thank you all for your help!