Whats going on here?

motoking_1990

motoking_1990

Active member
May 9, 2011
1,957
5
38
Terre Haute, IN
I must be getting blow by or something. Im starting to leak oil out of what looks like lower valve cover. I have been through the pcv valves and cleaned out the box under the fill neck. It still leaks oil pretty bad out the vent tube.

The oil around the valve cover has leaked on to the glow plugs and I can see bubbles coming for the center of them. Is it normal for air to come through the glow plugs? Something doesnt seem right and I dont know where to start.

My boost gauge is only showing 20 psi also. I thought it was a boost leak but its not. No shaft play and a rebuild turbo about 200 miles ago. Yes I have put 200 on it in two weeks.

Engine noise seems to louder than normal. Im talking about the usual diesel knock.
 
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motoking_1990

motoking_1990

Active member
May 9, 2011
1,957
5
38
Terre Haute, IN
Thinking I need to do a compression anyway and see where its at. Anyone find out what kind of pressures these things are putting out in the crankcase? Moparkxracer was looking into this, not sure what he found.
 
Dmax87

Dmax87

Member
Dec 3, 2013
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You could have a turbo issue. Kinda odd no issues then 200 miles after turbo was rebuilt this occurs and you're also low on boost. If oil seals fail in turbo it can put boost into the crankcase. Unfortunately it would be a bear to do on the dmax but on cat engines we have block off plates for oil supply and drain and then we hold the compressor wheel nut via vice grips to keep turbo from spinning and then test. Remove your oil cap and verify your blow by. If it's puffing then you more than likely have a cylinder issue, if you have a heavy steady haze I would be looking into a turbo issue. Hope this helps.
 
motoking_1990

motoking_1990

Active member
May 9, 2011
1,957
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38
Terre Haute, IN
The vent tube from the pcv has been leaking for some time now and the lower valve cover was leaking before I did the port and polish. I thought it was fuel coming from the filter housing. I rebuilt the housing and new filter. Its definitely oil from the lower valve cover. The gasket doesnt look blown.

It puffs blow by out of the fill neck but it doesnt push your hand if you put your hand over it.
 
OregonDMAX

OregonDMAX

NOT IN OREGON, NO DURAMAX
Apr 28, 2013
3,964
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Goodyear, AZ
Set the oil cap upside down on the fill tube, does it blow it off... If not then its what gm calls "acceptable blow by" which is horseshit but whatever.

I had a lot of the symptoms you describe and after doing a compression and leakdown test my results confirmed. I have roughly 275-310 psi across all cylinders and leakage was above 10% on 2-3 cylinders and 5-8% on the rest.
 
Yngdmax92

Yngdmax92

Active member
Sep 26, 2013
962
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take a video of the blow by and post it. a good duramax engine will have 400-450 psi if still healthy. check that as well
 
Yngdmax92

Yngdmax92

Active member
Sep 26, 2013
962
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OregonDMAX said:
Set the oil cap upside down on the fill tube, does it blow it off... If not then its what gm calls "acceptable blow by" which is horseshit but whatever.

I had a lot of the symptoms you describe and after doing a compression and leakdown test my results confirmed. I have roughly 275-310 psi across all cylinders and leakage was above 10% on 2-3 cylinders and 5-8% on the rest.
Click to expand...


do your truck still run? would be pretty impressive if you still daily drive it.
 
Yngdmax92

Yngdmax92

Active member
Sep 26, 2013
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that's crazy and impressive. I am starting to think that i don't give my stock block bottom end enough credit for what it is.
 
OregonDMAX

OregonDMAX

NOT IN OREGON, NO DURAMAX
Apr 28, 2013
3,964
8
38
36
Goodyear, AZ
Yellow Jacket said:
I've gotten 400-430 psi on engines duramax's before, but 350-400 is more common...
Click to expand...

Yeah see I'm not crazy. I knew 350-400 was more common I've done 3 now and never seen over but real close to 400 on the other two I did.


Here was my leakdown results, first time i ever had a shop touch my truck because I didn't have a leakdown tester and of course they break the aluminum heater hose and then have the nerve to tell me I have a leak...
Anyway my compression #'s correspond to the leakage #'s lowest being 275 and highest was 315
 

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motoking_1990

motoking_1990

Active member
May 9, 2011
1,957
5
38
Terre Haute, IN
I cant seem to find my compression tester. I bought a new one last year and loaned it to a buddy and i think he lost it. Gonna have to buy a new one I suppose.
 
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