so i have tried researching nad reading up on the issue and i just wanted to ask you all what you thought. I believe i have some blow by as stated before on my 6.9L. Its an 84 and everything is original,and from what i was told it has only 118000 miles on it. My questoin was is blow by a very serious issue? or can it be slightly overlooked and just keep driving the truck? i dont have money to have all the rings/etc replaced. I looked at autozone and saw some stuff on the shelf stating it helped seal up gouges/scrapes in the cyllinder walls and reduced blowby or my money back. Has anyone ever tried anything like this and had it work? Is any of the Lucas brand stuff good for adding to the coolant to help with head gasket cracks or oil additives to help with lubrication? sorry for such a vague question, but just want to know what you all use so that i can try to mimic and keep my baby running for many more miles!!!

 

well first of all i think it would be appropriate to ask what causes you to think that you are experiencing blowby?

 

Good point, my apologies. When I take off the oil filler cap, I have smoke puffing out. It isn't like the tailpipe, all thick, but a good wispy cloud. I was told that was a sign of blowby. Is there anything else I should look for that might indicate blowby or am I dead wrong? Haha

 

That is 100% an excessive blow-by situation. It could be a number of things including.. Worn cylinder walls, worn pistons and/or worn piston rings. basically whats happening is either your cylinder walls are worn and the space between the cylinder walls and piston is too large causing this blowby. or piston rings are worn and have became slightly smaller.. this will allow your compressed gases to freely travel past the piston and into your crankcase. It could also be your CDR valve. CDR stands for Crankcase Decompression Regulator. It's purpose is to recycle the exhaust gases that manage to get past the piston rings and into the crankcase. You could have a faulty CDR valve.

Referring to your initial question of using an additive to fix this blowby problem I personally wouldn't suggest it would do much good. I also wouldn't know, because I have never tried to use any of them. maybe someone else who has experience with them can chime in? good luck!

 

What Fordownsall says. But you still haven`t said why you are worried about it.
If it is not using excessive amounts of oil then just keep the CDR valve good and forget about it.

 

Thanks for the help guys. Its much appreciated! I was told by friends of mine and kind of got the impression it was a downhill slope if u have blowby. But I replaced the cdr valve this morning, old one leaked some oil, im hoping this new one doesn't!

 

Could you put a video up on youtube??

 

cool beans! let us know!

 

I can try to get one in the morning. At work now and will be too dark later. But definitely tomorrow ill get a video up. Y'all are a big help

 

Will do man!

 

the biggest test you can do is when it is puffing like that, you rev it, if it can suck the smoke back in and doesn't chimney anymore then it isnt too bad. They are normal when they look like a gasser that is worn out, its just they way they are but mine barely smokes if my oil is changed regularly.

 

I second what wreckinball says.

 

ill give it a shot in the morning. god only knows when the PO had this oil changed so im thinking a new project in a ffew days. oil change

 

wow yeah, bet that is more the problem than anything esle. Worn out oil will not help that situation and neither will a bad or gunked up CDR. Dont jump to rings and cylinder walls before the routine maintenance!

 

You got it chief. Try gettin all the goodies today. Not sure the wife likes my money spending lately. Hahaha