Hello, everyone. I did a blow by test today on my 2007 F-150 just for the heck of it. I unhooked the PCV tube from the manifold and plugged it off with a napkin. These are the results I got. Is this a normal amount of blow by gasses? There didn't seem to be any pressure puffing out at all when I put my hand on it, but just a steady flow of steam. Just curious to see what others think. Thanks.

https://www.youtube.com/watch?v=FGcg6c48AqE

 

@07F150Lariat5.4 Your test caught my fancy as a inexpensive and logical way to compare the health of my '04 5.4L (w/ 211 k mile) engine to the engines of my high school / hot rodding days of the 1960s.


So I replicated your test - with one minor thing you may have done but didn't mention. (I also plugged off the PCV filtered air intake line from the TB/filter box to the Bank 1 valve cover).


RESULT, IDENTICAL to yours. It would have looked like I just copied your video, I had videoed it.


I did note that if I sealed the oil filler spout with the 'heal' of my hand - for say 30 seconds or so, I could feel, and hear, a 'poof' of pressure built up as I removed my hand. Of course these sounds and feels are difficult to describe - but I would describe it on the order of Inches of Mercury, not PSI. I was pleasantly surprised as compared to the "blow by" I remember on engines of old with many less miles on them.


Thanks or the idea.

 

Thanks for the reply! I actually forgot to plug bank 1 when I did the video, so I redid the test today plugging both banks off and once again, still the same results. I did this because of the other videos I saw on YouTube and I wasn't exactly sure how much was normal because most blow by test videos are with diesels, but I didn't feel any puffing or anything. Mine also builds up pressure like you said yours did if I hold my hand over the filler cap neck for a bit.

I guess this is normal, then. I currently have 135,000 on it. Thanks, again.

 

Does not appear to be excessive to me. Does anyone else remember cars with 'road draft tubes' sitting at a light with a thick fog of oil smoke coming out from underneath? Now that was blow-by.

 

Yes I remember that, accompanied by the hot oil smell - because we all had 4/70 A/C back then.