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Username Post: Am I Crazy        (Topic#357855)
Posts: 73

Loc: Arizona
Reg: 03-13-09
08-28-19 08:27 PM - Post#2774360    

Last month I was bragging how I had nothing leaking under my 74 K-10. Took it out did a little 4 wheeling, my spare is a little to worn to 5 wheel. Came home on the freeway doing about 70 MPH for around 35 miles. Did a little more bragging as I pulled into the drive way about no leaks. I got out and oil had poured from the whole right side of the truck. I'm sure it came from blow by. over a qt.

I first ran a compression check and it was fine. I pulled the valve covers and made sure I had no restrictions in the oil passages. I rebuilt the 1990 350 a couple years ago and my emission readings are near zero. It hasn't done it since then but does anyone have a clue as to why it happened? My bragging?

Member #271 Senior Chevytalk Moderator
Posts: 25177
Loc: Austin, TX 78748
Reg: 05-09-00
08-29-19 05:01 AM - Post#2774372    
    In response to badbob85037

Where did the oil come out? Check the intake rear. At steep angles, a small gap there will spill oil. Is the dipstick in place securely? Is the PVC valve working properly?

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles
'08 GMC Acadia 3.6L SLE

"11th Year" Gold Supporting Member
Posts: 2123
Age: 70
Loc: south texas
Reg: 08-04-12
08-29-19 12:37 PM - Post#2774417    
    In response to badbob85037

motor oil, or ATF?


if you're gonna be a bear..................

1960 Biscayne (the 6T)
2005 Yukon XL
2007 GMC Sierra Classic 8.1
2009 Silverado
2011 Escalade ESV

Posts: 1246

Loc: Mission,BC
Reg: 02-03-05
08-29-19 02:15 PM - Post#2774423    
    In response to beagrizzly

Is it gear oil from the front diff?
Where is the vent ran to?

69 Canadian Pontiac 2+2 Convertible
Factory L48 350 Chev,TH350,PW,PT
99 Silverado RCLB 4.8 NV4500 14BSF 4.10's locker 6" Procomp 35'S
07 Town Car Loaded,Tinted,Getting Bagged

Whitetail Hunter 
Posts: 214
Whitetail Hunter
Age: 52
Loc: Green Bay Wisconsin
Reg: 03-28-15
08-30-19 08:09 PM - Post#2774534    
    In response to badbob85037

We're all crazy. It's not a competition....

Posts: 73

Loc: Arizona
Reg: 03-13-09
01-07-20 09:20 PM - Post#2783958    
    In response to 2plus2

My front differential vent is ran up passed the left headlamp. I'm sure it is coming out the right side dip stick or around the PCV valve. The PCV valve has been replaced because that is all I knew to do. I have never had blow by on a sound engine. The left valve cover is where I add oil. The rear hole in the cover is plugged as is the rear hole in the right cover. I'm 100% sure it's motor oil. It doesn't do it all the time and a couple days ago it did it for the first time driving in town going no more than 45 mph and it left a pretty big spill covering the frame half way back the truck. I'm going to install a vacuum gauge in the cab and see if I will notice any big changes while driving. I installed a new Edelbrock intake last month and have plenty of vacuum at idle. Timing at 8 degrees, new distributor.

Edited by badbob85037 on 01-07-20 09:35 PM. Reason for edit: No reason given.

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