Blowby with good compression???!!

[F35008]

I went to a diesel shop to get the #2 injector change because it was weak and it was throwing codes only for that cylinder, while he was running the laptop to confirm that it was really my #2 injector that was bad, he did a compression test and there was 3 cylinder that were a little low, #5 was 2% down, #6 was 5% down and #8 was 2% down, the rest was 100% good. Then he open up the oil cap to check blowby and he said that there was more pressure than normal. How can that be??? Cylinders are barely worn, 5% down doesn't seem low to me, is it?? Plus the truck runs really strong and I have 71000 miles on it. What you guy's think?

I will try to get a video of the blowby when i get a chance.

[dieselflash]

I would be checking the air filter,inlet hose,and turbo fins for wear, it may be getting dusted. Dirt inside a diesel engine will cause lots and lots of wear.

[Dylan08]

I have blow by at 78k miles and it almosted made me not buy it but my dad has a 08 with 40k easy driven highway miles and it has blow by as well

[08stroker250]

How much blowby are we talking about? A haze or is there enough pressure that if you set the cap on top without tightening, it is blown off? 6.4's have a decent amount to begin with.

[F35008]

My buddy did film the blowby cumming out of the oil cap, he said that he didn't want to let go the cap because he didn't want to lost it behind the engine but he feel that there was a little to much pressure for the cap to just sit on the tread, doesn't look good...


Here is the link:F350 2008 6.4 engine blowby - YouTube

[Eric@PTP]

All of the 6.4's I've worked on do that, its normal it seems for a 6.4 but I'm honestly not sure why.