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Discussion Starter #1
My first duramax, and hasn't been a great start.

I bought the truck with the last owner installing new grade c head gaskets, and arp studs. He works for a garage, and seemed to do good work. He assured me the heads were surfaced, and reinstalled correctly.

I recently have come across blow by. Puff-puff-puff from oil fill tube, and a steady pressure from the dip stick. I got a cyl 3 misfire code, and cyl 1,3,5 distribution/balance rate codes.

I figured cracked/hole in lo piston 3. Pulled all 4 glow plugs on passenger side, cyl1 had oil on the glow plug tube, and cyl5 had coolant on it. All 4 cylinders were 340-360lbs except for cyl 1 which was 390ish which I figured would be the difference of oil in cyl.

With that gasket being replaced so recently... what do I do... pull it again, install a new gasket... and retorque the studs? Would the engine side deck be so warped it could fail that quickly? I have enough experience to do the job, just dont want it to fail again after a short period of time.
 

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Discussion Starter #2
I havent filled sig out yet. Truck fully deleted, with exhaust, h&s mini maxx on performance tune
 

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Discussion Starter #3
Does anyone know how oil gets into the cylinder to coat the glow plug tube?

The cylinder tested good on compression. Just trying to figure out if I need to replace a head gasket, or if its cups leaking.
 

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What is a glow plug tube?
 

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Discussion Starter #5
The tube of the glow plug... not the element, but the tube that the element protrudes from. Maybe I should have said the shaft of the glow plug, where all the part numbers are located.
 

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Discussion Starter #6
I've got everything off the valve covers. Pulled all injectors and man are they dirty.

The po who did the head gaskets last time reused the copper washers and body o-rings.

How does the coolant get to the injector body to bake itself to the injector like this?
20200707_193756.jpg
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20200707_193805.jpg
 

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Discussion Starter #7
Is there any write up about removing the head from the intake without removing the turbo? Or can someone point me in the right direction for a starting point?
 

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Is there any write up about removing the head from the intake without removing the turbo? Or can someone point me in the right direction for a starting point?
Are you trying to remove the intake runners without pulling the heads? If so, it's probably difficult but you might be able to do it without removing heads or turbo. If you are removing the heads, you don't need to pull the runners or turbo to do so. The heads and intake runners would come off as one piece.
 

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Discussion Starter #9
I'm trying to pull the passenger head. In order to separate the head from the intake plumbing the easiest... do I disconnect it at the y-bridge? Somehow get that lower turbo side bolt out... that was my confusion with whether I need to pull the turb or not.

But thankyou for the reply, I was starting to lose hope with getting any help on this forum. I guess I was exceptionally spoiled on the cummins forum with a plethora of people looking to help.
 

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The Y-pipe would need to be disconnected along with fuel lines and fuel rail.
 

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I’ve got mine pulled apart right now. I’ll be glad to help with any pictures you need.

If you’ve got oil on your glowplug, it’s either coming in thru a bad head gasket, or you have bad valve seals. My guess would be bad seals. If he didn’t take the time to replace the injector coppers, I really doubt that he had the heads pressure tested, or put in new valve guides and seals.

Injectors and fuel lines need to come off. Accessory bracket and coolant crossover pipe. Should be pretty obvious once you dig in what needs to come off.

What is your current plan for repair?


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Discussion Starter #12
Plan as of now is pull the head and pressure/flatness check it and see if it can be machined (again) if it was even done the first time. Only have the pulley system, y bridge, and rail to pull off as of now. Top valve cover was never removed by the PO. Only lower by the looks (grey rtv sealant).

I have the injector seal kit.

New fuel return line. (slipped wrench)

I've got the 9th injector delete stuff.

Gonna put in that updated mpfp or whatever sensor on the cp4. Also check for metal on the screen while I'm there.

C MLS gasket is on its way.

If everything runs fairly cheap, I'll go with a lift pump and oem filter head delete since its problematic.

And the shop will further guide me with the running condition of the head. They're good, and reputable around here. North East Performance diesel is who I believe I'll use.
 

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With the discoloration, it looks like it saw a good bit of heat sometime. I personally wouldn’t want to put it back together without decking the block too, but YMMV. Should at least check the block deck for flatness with a straight edge if you have a true straight edge. Check your cylinder walls for scoring.


Upper valve covers really never need to come off.

Plan on doing drivers side as well?


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Discussion Starter #14
Yes, good point I did mention the block deck earlier so I surely plan to check that.

It's always hard to tell how thorough someone else is when they work on something... and his lack of injector seal replacement leaves me in question.

I do not plan on doing drivers side. Upon pulling glow plugs, they were all clean. I however do plan on doing the injector seals for sure.
 

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Discussion Starter #15
Were you referring to heat discoloration on the injector somewhere? The other 3 on that side were very clean and didnt show any signs of excessive heat IMO. I'll post a pic later n see what you guys think.
 

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Discussion Starter #16
Does that rocker arm shaft come off as easy as it looks? 5 bolts and then sinply remove spring bridges and push rods?

Just dont want to remove anything that may be under tension.
 

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They are under tension, but yes, 5 bolts and the rocker arms come off. Pushrods and bridges come off as well. A few more bolts for the lifter holders, and you can pull the lifters out too.


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I was referring to discoloration on the block.


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Discussion Starter #19
I picked up the head today. Shop tech said he spotted a clear leak on cyl 5, and 1. Which makes sense from the contaminated glow plugs I found.

He also mentioned almost every valve seal was split in half.

I told him I was concerned with whether or not the head could be machined again, and he said he would mic it to make sure. He said with the valves fully open, that the measurement was well within spec to the point where it could be resurfaced again if need be.
 

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Discussion Starter #20
So here is my next question. Once I get the head torqued down... at that point do I set the valve lash, and confirm that the pistons dont contact the valves? That would be done by rotating engine by hand via crank pully?
 
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