Blow By Tube!!!!
#18
Leaking out of crank vent tube
My truck did the same after I had changed the oil to synthetic. It was blowing the water out of the test hydrometer about 18"hg. Other than that and puking oil and smoke out of the breather tube it was running fine. We changed the oil back to regular Rotella 15w/40 and ran her hard and hot. We then retested the crank pressure and it was back down to 4"hg. Problem fixed. After a lot of testing and head scratching it was just the oil. Don't use synthetic or even semi synthetic!
#19
Registered User
I'll have to look at my vacuum lines. Mine leaves marks everywhere it parks and my front differential is soaked.
#20
Its amazing what you hear come from the mouth of professional mechanics..... This is why I ALWAYS highly suggest that if you're going to have a mechanic touch your vehicle then make absolute sure that they are proficient in the vehicle you're wanting to work on. I was a mechanic before realizing that working on grandma's Cadillac wasn't what I wanted to do forever and just because someone works on cars does NOT mean they know anything other than how to turn a wrench.
As for the blowby, clearly torquefan's diagnosis is right on the money. This is a vacuum pump leaking and blowing all that air in the crankcase and keeping your vent selector from working. But that said, these engines are open loop and do vent their crankcase vapors directly into the atmosphere, so you will always see some air coming from the blowby catch bottle. The correct amount of blowby would be compared to about how forceful you could blow air out a 3/4" hose with your mouth. Also, after changing the oil you may notice more blowby stink, especially with certain oils. The 5-30 Mobile is fine and didnt hurt anything other than your pocket book. Same goes for the Amsoil. Although 5-30 is too light unless its really cold out.
I wont turn this into an "oil thread" but if you do a simple thread search about oil's and what to use, you'll quickly see that its all personal preference and those threads tend to turn into a heated and argumentative discussion. So the only things I'll say about oil is DO NOT use Fram filters. Other than that.....
As for the blowby, clearly torquefan's diagnosis is right on the money. This is a vacuum pump leaking and blowing all that air in the crankcase and keeping your vent selector from working. But that said, these engines are open loop and do vent their crankcase vapors directly into the atmosphere, so you will always see some air coming from the blowby catch bottle. The correct amount of blowby would be compared to about how forceful you could blow air out a 3/4" hose with your mouth. Also, after changing the oil you may notice more blowby stink, especially with certain oils. The 5-30 Mobile is fine and didnt hurt anything other than your pocket book. Same goes for the Amsoil. Although 5-30 is too light unless its really cold out.
I wont turn this into an "oil thread" but if you do a simple thread search about oil's and what to use, you'll quickly see that its all personal preference and those threads tend to turn into a heated and argumentative discussion. So the only things I'll say about oil is DO NOT use Fram filters. Other than that.....
#21
Registered User
fram filters? Does that include fuel filters as well? I'm just curious being that I had put one on. The orange drew me in.. my truck hasn't ran right though before and after that.. i been reading these posts and I'm gonna check my vacuum hoses. I got dead pedal. And hard starting. I need to fix it asap. Having no luck
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Diesel-Dan
12 Valve Engine and Drivetrain
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11-06-2016 12:31 AM