Engine/Transmission (1994 - 1998) Help, blowing oil at 70 mph

[grease man]

my friends 96 4x4 2500 5 spd , is blowing oil out of a plastic tube that comes from the engine on the left side and terminates right at the front u joint

he sayes he changed the oil , fuel ,and the air filters and that it only does it when he drives at 70 mph or better, also he said that the oil pressure guage readings are normal , he thinks that something is pressureizing the crank case

what could this be ?

 

[Vaughn MacKenzie]

Hi grease man, how many miles on the truck? Did it start all of a sudden? Things that may cause it are a leaky headgasket or possible broken ring. Mine sorta does the same thing, it runs great but it's using more oil than it should and I can't figure out where it's going. At idle very little mist comes out the tube but when I drive it hard down the highway I get black specks on the back of my truck. I did a compression check and it's a little weak on cyl #1 but it was still 500psi, the others were 520-525.



Vaughn



Vaughn

 

[Smokey96]

Mine does the exact same thing. It blows oil all over the tailgate and undercarrige.

 

[Forrest Nearing]

mine does the same thing... 70ish? no problem... crank it up to 80-85, and it's all over the tailgate!!



I think the constant boost and the higher windspeed blowing across the road draft tube does it... I've got about 240k on it. really freaked me out when I bought the truck w/ 208k on it... but it runs like a champ. I keep meaning to modify a baby bottle to hang on there... drill some holes in the top, and wrap a sock around it, and see how it does.



Wes Snow was telling me that his truck used to do the same thing really bad, but when he put a baby bottle on the road draft tube, there was barely any oil in there... I think it's the wind speed over the road draft tube more than anything.



Cummins spec on oil consumption is something crazy like 1qt per 500 miles! LOL!



Forrest

 

[Smokey96]

It only takes 60 mph to be all over my tailgate but I have 4:10 gears so it might do it just over a certain rpm. I'm using a gallon every 300 miles!!!!!

 

[Forrest Nearing]

yeah, the higher the RPM, the more the oil is gonna get whipped up in the crank case... a gallon every 300 miles is excessive... you SURE you're not overfilling it? I did that for a while when I first got the truck... I kept overfilling it because it was putting so much oil on the tailgate... I studied the oil level a little more closely, and noticed that it would fall to a certain point and then just hover there...



and when I bought the truck, the kid had just done a new timing cover and oil pan gasket, so the oil wasn't leaking from anywhere else... just vapor from the road draft tube.



also, if you're towing heavy, that'll make a difference, because you're going to have more blowby under steady moderate boost.



Forrest

 

[Smokey96]

I'm positive that I'm not overfilling it and it does it even when I'm not pulling

 

[Vaughn MacKenzie]

Forrest, Grease Man, how much oil are you guys using?



When I went on a trip across the US late this fall I towed a trailer from the NW to Maine, Florida, Texas then home. In 9000 miles I used only 4qts of oil, and often I drove dozens of miles on end at 20+ lbs of boost.



Starting about 2 months ago my oil consumption suddenly more than doubled and that's when the black specks on the tailgate appeared. I use a quart every 500-700 miles. I did have a few droplets that landed on the trailer and tailgate during the trip but very little. Not sure why. Truck had 353k miles when I set out on the trip in September and I'm at 367,935 now.



Vaughn

 

[WMonroe]

I'm using about 2 quarts every 3000 miles but I have a leak from the oil pan gasket, timing cover gasket, and/or front oil seal.

Will

 

[Jeff H]

I thought I had a real problem till I saw this post. My oil level will be right at top of dip stick marks. By about a 1000 mile or so it would be at the half way mark on the dipstick and stay there till my next oil change.

On cool or cold days I can see the vapor coming out of the tube pretty good.

This year I pulled the tube and cleaned it out. I just took some degreaser and wadded up some paper towels. Then shoved it through the tube.

One thing if you think you have really exesive blow by. You can have it measured with a mamometeter. Then go from there.

 

[Forrest Nearing]

Vaughn,



honestly, I quit really paying attention to how much it takes vs. distance traveled... this truck has led a hard and heavily fueled life... I can't afford an engine refresh right now, so I try not to think about it



it still runs like a scalded dog, so I just check the oil whenever I fuel up. if it's low, I top it off... if not, I leave it alone.



Forrest

 

[RVPILOT]

oil leaks

Air Sep of Sun Valley, Ca. This might be a good option for high milers like mine, Air Sep makes a device that closes off the crankcase creating a vacuum and recycles the oil back into the oil pan. I installed one on mine in early Dec and it eliminated the oil leaks. It's expensive but it's cheaper than replacing the pan gasket which I was contemplating. Stormy

 

[WMonroe]

How does it create a vacuum? I always thought if you seal off the crankcase pressure would build up till a seal or something blew.

Will

 

[RVPILOT]

oil leak

If you get on their web site, www.walkerairsep.com their is a complete descriptiion of the product and how it works. Stormy

 

[WMonroe]

I understand now. I guess I just needed some pictures.

Will

 

[Swayse]

I got my blow by going into my exhaust. Welded a pipe into my exhaust pipe at a 45 degree angle, it sticks into the exhaust about an inch. It has a little bit of suction on it like this. I stuck a vacuum guage in the dipstick tube and run it down the road. I got just a very little bit of vacuum in the crank case at a normal cruise. At 60 psi manifold pressure, I've got like . 1 psi in the crank case. I really like it. I have fixed all the oil leaks on my truck, and my blow by don't leak, feels like a better than new truck.



The only bad things about my set up are that it has an exhaust leak sound coming out of the exhaust pipe, and after a hard run, the exhaust smells like burning oil.

 

[Rdunkin]

My KDP cracked my timing cover and I am getting oil spots on the rear bumper and trailer. I'm going to fix that sometime... ... ...