Blowing oil out the filler cab and pvc valve. HELP! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

skyhawk1 · 02-06-2003, 08:15 PM

My son's 70 K-10 is blowing oil out the oil filler cab and out around the pvc valve. Somebody please tell me why!

Project1970 · 02-06-2003, 08:29 PM

Sounds like mass blowby (piston rings) or a clogged PCV valve. Check the PCV valve first; hell, just replace it, it's about $2.

If that still doesn't do it, I'd look into adding another breather; say, as a replacement to the oil filler.

cableguy0 · 02-06-2003, 08:59 PM

do u have a breather at all on the motor now??

skyhawk1 · 02-06-2003, 09:03 PM

My son replaced the pvc valve and the oil filler breather with new ones, and it still does it. Oh by the way, we are not getting any smoke out of the exhaust.

casey · 02-06-2003, 09:36 PM

From what I understand blow by is from combustion getting past the rings into the crank case, Did this just start or has it been doing this for quit a while? I had a worn out blaser s-10 2.8 that had major blow by, and just to keep the oily mess out of the engine compartment, I ran a 2" hose from the oil filler , down the side of the block, so it would spray out under neath the truck, It was hooky, but it worked, that or rebuild the motor

greasemonkey · 02-06-2003, 09:58 PM

It's from a broken or extremely worn piston ring. Mine has blowby and no smoke out of the exhaust so it is possible. Some people try products like Restore, I tried unsuccessfully. Just put some 20W50 in until you can rebuild it, that slows it a bit.

Fred T · 02-06-2003, 09:59 PM

Is there vacuum to the pcv valve? If there is, do a compression check to look for the leaky cylinder(s).

da-burb · 02-06-2003, 10:05 PM

In the old days the auto manufacturers called the old hose trick a "road draft tube". My younger brother used 3 feet of garden hose on one of his old beater cars.

02-06-2003, 08:15 PM	#1
skyhawk1 Registered User Join Date: Dec 2000 Location: Oceana WV USA Posts: 184	Blowing oil out the filler cab and pvc valve. HELP! My son's 70 K-10 is blowing oil out the oil filler cab and out around the pvc valve. Somebody please tell me why! __________________ "The World's a Mess"! 71 C-10 72 Suburban 2WD Oceana, West Virginia

02-06-2003, 08:29 PM	#2
Project1970 14.1 @ 96MPH Join Date: Jul 2001 Location: Mesa, AZ Posts: 2,811	Sounds like mass blowby (piston rings) or a clogged PCV valve. Check the PCV valve first; hell, just replace it, it's about $2. If that still doesn't do it, I'd look into adding another breather; say, as a replacement to the oil filler. __________________ Project1970 - LS1 Swap Complete!

02-06-2003, 08:59 PM	#3
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	do u have a breather at all on the motor now?? __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

02-06-2003, 09:03 PM	#4
skyhawk1 Registered User Join Date: Dec 2000 Location: Oceana WV USA Posts: 184	My son replaced the pvc valve and the oil filler breather with new ones, and it still does it. Oh by the way, we are not getting any smoke out of the exhaust. __________________ "The World's a Mess"! 71 C-10 72 Suburban 2WD Oceana, West Virginia

02-06-2003, 09:58 PM	#6
greasemonkey Registered User Join Date: Dec 2001 Location: Pace, FL Posts: 2,155	It's from a broken or extremely worn piston ring. Mine has blowby and no smoke out of the exhaust so it is possible. Some people try products like Restore, I tried unsuccessfully. Just put some 20W50 in until you can rebuild it, that slows it a bit. __________________ 1942 Master Deluxe 1969 C/10 1985 Blazer CUCV 1987 Jimmy 2004 Tahoe 2005 Silverado 1500 2005 Silverado 3500

02-06-2003, 09:36 PM	#5
casey Registered User Join Date: Jan 2003 Location: Kelowna B.C. Canada Posts: 2,048	From what I understand blow by is from combustion getting past the rings into the crank case, Did this just start or has it been doing this for quit a while? I had a worn out blaser s-10 2.8 that had major blow by, and just to keep the oily mess out of the engine compartment, I ran a 2" hose from the oil filler , down the side of the block, so it would spray out under neath the truck, It was hooky, but it worked, that or rebuild the motor

02-06-2003, 09:59 PM	#7
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	Is there vacuum to the pcv valve? If there is, do a compression check to look for the leaky cylinder(s). __________________ Fred There is no such thing as too much cam...just not enough engine.

02-06-2003, 10:05 PM	#8
da-burb "Ochre Ogre" Join Date: Apr 2000 Location: Springfield, MN Posts: 3,558	In the old days the auto manufacturers called the old hose trick a "road draft tube". My younger brother used 3 feet of garden hose on one of his old beater cars. __________________ Bowtie Truck Stop Inc. Mid-West GM Truck Restoration Parts Supplier Your Key Parts, Auto Metal Direct, Dynacorn, and Goodmark dealer. like us @ www.facebook.com/BowtieTruckStop 1971 C-10 Suburban (Ochre) 1971 K-10 Suburban (Ochre) 1972 C-10 Suburban (Ochre) 1972 K-20 Suburban (Yellow- that just aint right!) Springfield, Minnesota 56087



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