Loud pop, no power, low coolant LLY

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10-04-2012, 19:25
220cummins

Loud pop, no power, low coolant LLY

So I think I blew a head gasket tonight. I was merging on the local highway (parkway-Pittsburgh) when I heard a loud pop and then loss of power. I immediately pulled to the shoulder and looked for what I thought would be a turbo hose or piping that poped off to and no sign of any leaks of fluids. I get back in the truck and drove about an eight mile to try to make it to the next exit only to see the low coolant light flash and smoke in the mirrors. I immediately pull back on the shoulder and shut it off. I'm sitting on a very good hill and the dipstick shows some over the full line plus it's water there too. So after a quick phone call to my dad to grab my Mack B-61 and some chains he's on site and were hooking up the chains for a pull back to the shop. So back we go hooked up 4 feet apart with the flashers going. We go past 2 police officers bullsiting in a parking lot without and care then pass another police officer right before we get back to the shop. I guess the couldn't see the chains and didn't think twice about the truck behind the old Mack since it has a utility body on it. BTW the truck is a 2005 GMC Sierra k3500 with 138k miles on it. I am the second owner with the first being a fleet. This is my second LLY in the past 6 years. I sold my last one before it turned 100k then i bought a k3500 silver ado with a gas job in it before purchasing this truck on Monday 10-1-2012. That right less than 5 days in my possession. I'm pretty sure I'm it's the head gaskets which I plan on replacing along with the studs. Ive worked on class 8 Mack, Cummins, Cat engines and even smaller Waukesha and allis diesels. My questions are as follows. Is there anything I need to know before I go and pull the heads off and send them to the machine shop and it is a standard head gasket replacement?The next question would be does anyone think the turbo would have been affected or harmed since the load pop and loss of power immediately?? Thank you
10-05-2012, 07:44
rapidoxidationman

In my experience doing the gaskets on an LLY:
The center intake manifold can be tricky to remove and install - there are 4 fasteners on either side of it and the ones under the turbo are difficult to get to. The driver's side head is harder than the passenger side only because the rear head bolts or studs hit the firewall before they come all the way out. A rubber band to anchor them in the head will help make it easier. There's an exhaust heat shield on the driver's side that needs to be removed to get the exhaust pipe off the manifold. Small hands are an asset.

Of course, if you remove the cab from the truck all these problems go away...

I'm curious to hear what you found the loud POP to be and will be following this thread. Hopefully you won't find that a ton of water got into a cylinder and bent a rod...

I found Alldata DIY to be a great help, especially with torque numbers and valve clearance specs.

Good luck!
10-09-2012, 18:53
220cummins

Thanks for the alldatadiy tip. I've used it in the past with good luck and have already used it to check the egr cooler on this truck. The loud pop was as I suspected a lower intercooler hose that the clamp broke off. That's one problem fixed. Now to the head gaskets. I checked the egr cooler first since it had to come off anyways. It's carboned up by still working. I have the engine about half way tore down so far. I'll keep this tread updated. From what I seen and heard, head gaskets are a common thing around this mileage.
10-21-2012, 05:32
220cummins

Finally got the engine pulled. It was a bit tight on the dowel pins but a little bit of pb blaster and a screw driver in the slot at the bottom of the bellhousing separated the allison from the duramax. I decided to pull the engine the conventional way since I do not have a lift to just take the cab off. I also need to fix a wet rear seal and check the bearings since the pan was filled up with coolant.
10-26-2012, 15:26
More Power

Thanks for keeping us updated. Be careful with the dowel pins that the transmission is keyed to. They can sometimes come loose from the aluminum adapter.

If I were doing this I'd look the head gasket over carefully, looking for an obvious coolant track that would indicate the source of a coolant/oil situation. Knowing how that happened would add confidence that re-assembly with new gaskets and head bolts will cure all ills....

Jim
10-29-2012, 11:30
lmholmes11

Do you HAVE to pull the engine or cab to do head gaskets? Or does it just make it easier? Do you have to with the lbz?
10-30-2012, 08:57
220cummins

I had to pull the engine because I do not have a lift to pull the cab. I can't figure out how I would have got the bolts for the uppipes on the turbo and the bolts for the turbo off without pulling it. I did have a dowel pin that suck in the engine. I soaked the crap out of both of them too. Since the engine is on the stand I'm replacing the drivers manifold with the LML manifold that I got from GM for $75.00. I am also doing the pcv reroute, egr delete but keeping all the egr setup there (Tig welding up the ports on the cooler) and splicing in the Finger Stick, ported stock mouth piece, and mbrp 4" turbo back
exhaust with muffler. I am also debating doing ARP studs. I have no plans of adding more boost than stock.I just got the heads back from the machine shop. They check out good and were milled only to clean up where the gaskets were. I plan on going with the grade "c" hg from gm. Since everything is easy to get to should I replace the water pump? I've seen some posts on other sites pointing to the water pump as issue contributing to head gasket issues with the LLY.
01-23-2013, 08:25
220cummins

Quote:

Originally Posted by 220cummins

I had to pull the engine because I do not have a lift to pull the cab. I can't figure out how I would have got the bolts for the uppipes on the turbo and the bolts for the turbo off without pulling it. I did have a dowel pin that suck in the engine. I soaked the crap out of both of them too. Since the engine is on the stand I'm replacing the drivers manifold with the LML manifold that I got from GM for $75.00. I am also doing the pcv reroute, egr delete but keeping all the egr setup there (Tig welding up the ports on the cooler) and splicing in the Finger Stick, ported stock mouth piece, and mbrp 4" turbo back
exhaust with muffler. I am also debating doing ARP studs. I have no plans of adding more boost than stock.I just got the heads back from the machine shop. They check out good and were milled only to clean up where the gaskets were. I plan on going with the grade "c" hg from gm. Since everything is easy to get to should I replace the water pump? I've seen some posts on other sites pointing to the water pump as issue contributing to head gasket issues with the LLY.

I ended up replacing the water pump and did all the mods except the mbrp turbo back. I put everything back together and the truck fired right up! Its been 3 months but I finally have the truck on the road after closing on our first house. WOW what a process, I mean the house!