LB7: 02 Duramax blowing oil out of breather pipe

Guns and Grease

New member
Apr 12, 2011
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0
Northern WI.
I just bought a 2002 silverado. The owner told me the injectors, pumps and regulator were replaced 5000 miles ago. Visually it appeared like the covers were off and new things installed. After getting it home and going inside to get my wife to show her what I just spent $10,000 on, I came out to see oil dripping on the driveway... a definite bummer. So after she inspected it and found literally no rust on the body or under the doors she says "How many miles are on it?" I says 320,000.... she asked me again figuring she heard me wrong... nope.
She goes in and I start looking for the cause of the leak. It's coming from the breather. I check the oil and it is at the top of full. I jump in it and drive for an hour and recheck the oil still the same. That's when I found this site and info on an old PI from GM about the PCV valve being stuck and not allowing the PCV reservoir to drain back to the oil pan. I ordered one and took the old one out and a cup of oil drained out and the PCV would not let me blow through it towards the oil pan, the new one does. So far no drops on the driveway tonight.

Sorry for the long story but I figured someone might just overlook this $20 of indigestion relief.
Thanks for the info!
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,258
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Mid Michigan
I thought the PCV system was non-serviceable. Nice to hear you were able to fix it.
 

Guns and Grease

New member
Apr 12, 2011
11
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0
Northern WI.
Nope not CA. The LB7's have a hose from the tee between the valve covers to the alternator bracket, which has a cavity in it, the drain to the oil pan has a PCV screwed into it and a hose going to the block. The breather pipe comes out of the alternator bracket at a higher point and then goes down and is open to the air at the right front of the engine. The cavity holds about a cup of oil. When the engine is off the PCV opens and allows the oil to drain into the pan. If the PCV is plugged the cavity will fill up and overflows out of the breather pipe. This seems to happen more after a hard run or pulling hard, at least on mine it did. So replacing the PCV. which you can see through the right wheel well. It looks like an oil pressure sending unit and has a hose clamped on the bottom running straight down. The part number is 97302067, list price is $41.34. This cured my oil leak from the breather, no leaks again tonight! So if you aren't making oil and leaking out the breather this might be the answer for you.
 

Guns and Grease

New member
Apr 12, 2011
11
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0
Northern WI.
Thanks for the warm welcome. I own a small auto and motorcycle repair shop...we also are a firearms dealer... hence the screen name, but up until now I had no interest in taking in any diesel trucks for repair, but I guess since I now own one there won't be any excuses, plus I might learn something. LOL
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
15,258
1,543
113
Mid Michigan
Thanks for the warm welcome. I own a small auto and motorcycle repair shop...we also are a firearms dealer... hence the screen name, but up until now I had no interest in taking in any diesel trucks for repair, but I guess since I now own one there won't be any excuses, plus I might learn something. LOL

You came to the right place for that. :thumb: Good find on the PCV valve.
 

elpski

New member
Nov 20, 2015
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0
2003 duramax spewing oil.

so i just bought an 03 chevy duramax. the day i bought it i drove it like 50km before i noticed oil puddle underneath the truck where ever i parked. i am fairly new with diesels. but was doing some reading on this site and most say injectors but i sniffed it for diesel and i couldnt smell diesel. neither could my buddies. the oil level is low and not high like it has fuel in it. also tried the oil on the paper towel trick and could only see oil. anybody have any info on this? would like to try avoid doing injectors right away. thanks in advance.