blow by
 

i happend to see that blow by was something to look at when buying a truck in another thred ..... my truck has some BLOW BY! like a good steady steam coming from the hose on top of the valve cover that leads to my intake .... i just took it off today and pointed it toward the back of the moter ... ha ha what does this meen?

It means you have got some miles on that rig.
All diesels have some but you are getting some compression in your crankcase usually going by the rings.

230klm is whats on it .... and it does blow blue when i start it up but goes away when warmed up i hope my frickin moter is not shot ...

The blue at startup is valvestem seals I have seen rigs run forever and not use much oil like that.

Mines gotta good bit of blow by, but hardly uses any oil.

That 22.5 to 1 compression is what gets ya, it doesn't take hardly any gap at all with that kind of pressure to get a little compression in your crankcase.

ooh I just remembered, have you serviced your CDR? Its whole job in life is to relieve the pressure out of the crankcase, so it may be real dirty, thus not letting the pressure out, thus causing some of your blowby.

Before you start worrying about blow by, look at this:

YouTube - 1985 Ford 6.9 IDI Blow By Take Two

That video shows normal blowby at the filler cap and thats nothing to worry about. If you can feel actual pressure under there while the breather system is hooked up, then you might have a problem. One of the old school ways to check for how much is too much is to leave the filler cap in place but not turned to the lock. If the blowby pushes it up, then its too much.

CDR??? haha what is that? and does anyone have pics of where it is located an idea on price and or if it can just be cleaned thanx



i have that much if not more blow by out of the filler i have not done the cap check yet tho but i got crazy amounts coming out of the end of the hose coming from my valve cover and now when i open my filler car it sounds like the inside of my moter is screaming at me kind of a high pitch i dont know if i remember it doing that before

The cdr is what your hose your talking about is hooked to. You can clean it soak it in gas and swish it around do not use compressed air as it will ruin it.
You will have some noise out of your oil filler cap as the gaers are noisy that is the only reasons most gassers had a timing chain instead.

thanx is there a way to tell if its not working and in need of a new one after i clean it?

There probably is bit I don't know it . I do know if you get pieces of rubber out of it you need a new one. It is basically the same as a pcv valve on a gasser.

All you can do with the CDR to make sure its working (after the mentioned cleaning) is inspect it and make sure the rubber diaphragm isn't falling apart.....or just replace it with a new one.

The vapors will come out of the valve cover with more speed because the opening is smaller. Again, thats probably not much to worry about. If you look closer at that video I posted, you will see that the vapors get pulled back in if the engine is revved up a little. If yours does that, then its normal.

There will be high pitched noise comming out of the filler cap from the timing gears, not really loud but enough to notice. I suspect what you are hearing there is also normal.

Well I cleaned it and no change. I could not see any rubber maybe its stuck open or closed...? And now I think I may have a rear main seal or pan leake this truck is really getting on my nerves

if there is no oil on the fly wheel and clutch is there a chance that it could be my main seal? or maybe just pan i have not had the chance to get underneath it with a wrench yet to see if maybe the pan is loose at the rear or maybe its just the gasket i cant remember can you pull this pan without pulling the moter ?

Any leak on the top or rear of the motor can and likely will drain down the back of the engine to the access cover of the transmission. If your CDR grommit in the valley pan of the engine isn't sealing perfectly, that can already send oil down the back of the engine during idle conditions.