Help: Head Gasket suspect failed

Danimal

New member
Nov 5, 2011
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Saskatchewan, Canada
So I just got my truck back after basically upgrading everything in it. It took me 17 hours to drive the thing home and up until the last leg of my journey everything ran beautifully. My DSP5 has a big tune that should run me around 1100hp and the whole truck was designed and built to handle it but I am still getting used to the truck and haven't even flipped to the 4th or 5th stages yet. I found an open stretch of highway with no one on it and did a short run on the third tune (less than a 1/4 mile). Then I came to a stop at an intersection and my oil pressure dropped to zero.

I shut the truck down but could find no oil leaks and my oil levels were right where they'd been all day (every fill station I made sure to check oil). I started it back up and the pressure was ok.

In the morning I did some troubleshooting, my oil pump is fine. I found that pressure only drops to zero at low idle at or under 800RPM. I took the truck home and changed the oil and the pressure seemed to hold better although still a bit low. I took it for a drive and as soon as I got back it started doing the same thing. I could smell something coming off the engine but couldn't see anything in the dark. This morning when I started it I had white exhaust, I drove it 20km's and when I opened up the hood I found that the breather is venting vapor on the driver side. This is a pretty clear indication to me that the head gasket has failed.

Is it possible to replace the head gasket without pulling the engine?


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TeaBagger2006

Im a Garrett Nut Swinger
May 11, 2008
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Bis ND
Do a compression test on all the cylinders. How is the truck running? When you crack a piston the engine runs like garbage
 

TeaBagger2006

Im a Garrett Nut Swinger
May 11, 2008
3,123
15
38
Bis ND
Is there any fuel in your oil? Can you check the balance rates on the injectors? Shouldn't have blow by that is visible. You have a built motor, right? Is your cooling system getting pressurized?
 

Danimal

New member
Nov 5, 2011
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Saskatchewan, Canada
No fuel in oil that I can tell. I have no means to check the ratios. The venting vapor on the breather tube was definitely visible though. Ya this is on a built engine.


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JoshH

Daggum farm truck
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Feb 14, 2007
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I've never seen a head gasket blow between a coolant and oil passage. Every one I've ever seen it pressurizes the coolant so that when you go out to the truck when it it cold, it still has lots of pressure on the upper radiator hose.
 

JoshH

Daggum farm truck
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Vendor/Sponsor
Feb 14, 2007
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I can't give you any insight on the oil pressure, but the white smoke and vapor coming out of the crankcase breather can easily be explained by the brand new built motor. Most built motors run lower compression and larger injectors that will normally white smoke especially when the engine is cold and it is cold outside. The vapor is probably a little excess blow by from new rings not being fully seated yet.
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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I can't give you any insight on the oil pressure, but the white smoke and vapor coming out of the crankcase breather can easily be explained by the brand new built motor. Most built motors run lower compression and larger injectors that will normally white smoke especially when the engine is cold and it is cold outside. The vapor is probably a little excess blow by from new rings not being fully seated yet.

x2. mine would puff white on first start up even in 100+ degree weather till she finally start breakin in. took about 3,000 miles. Danimal, watch your oil level too. it will eat some oil till shes fully broke in. I have 6k on my motor and its finally starting to stop using up oil.

Danimal, have you done the paper towel trick to see if its fuel in the crankcase? have you given trent a ring for some ideas?
 
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Danimal

New member
Nov 5, 2011
45
0
0
Saskatchewan, Canada
x2. mine would puff white on first start up even in 100+ degree weather till she finally start breakin in. took about 3,000 miles. Danimal, watch your oil level too. it will eat some oil till shes fully broke in. I have 6k on my motor and its finally starting to stop using up oil.

Danimal, have you done the paper towel trick to see if its fuel in the crankcase? have you given trent a ring for some ideas?

Ya Trent and I have been working together over the phone to try and figure this out. I'm not familiar with the paper towel trick though?... I'm headed up to work for a week now but when I get back I'm gonna change out the oil again and replace the sensor. See if i can see anything in the oil And if it is just a sensor. My levels don't seem to be changing much but the oil pressure still drops to zero when the engine is warm and I come to an idle.


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Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Ya Trent and I have been working together over the phone to try and figure this out. I'm not familiar with the paper towel trick though?... I'm headed up to work for a week now but when I get back I'm gonna change out the oil again and replace the sensor. See if i can see anything in the oil And if it is just a sensor. My levels don't seem to be changing much but the oil pressure still drops to zero when the engine is warm and I come to an idle.


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the paper towel trick, you pull your dipstick out of the engine oil and let a drop of oil drop onto a flat peice of paper towel. After the oil seeps in, you should either see like a little halo around the oil spot or no halo. the halo means you have fuel in oil but being you have an LBZ, it really would only indicate something with injectors as all the hard lines are outside the valve covers unlike my LB7. i wouldnt use it as a difinitive answer to anything but may help point to something else