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Duramax head gaskets....RESOLVED

rpf500

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Location
Evansville, IN
I'm hoping someone here has experience or some knowledge to share.

Driving home today with maybe 2k on trailer. 5 hours running 75mph average. Got home and noticed wet inner fender liner passenger side. Narrowed it down to the coolant overflow tube. Started reading forums and sounds like head gaskets. Could be rad cap or thermostat, but since it's my luck, it won't be easy or cheap like that.

1 thing to note...I recently installed an edge programmer. When I got fuel an hour from home I apparently switched from level 2 to 3. I guess while I was looking at some info while waiting on the slow pump. May or May not be a factor but I'm sure it's not ideal.

Any thoughts? Has anyone done gaskets on these trucks? I'm reading on Duramax forum people pulling the engine to do the job!!!

Apparently I should be able to squeeze the upper radiator hose in the morning and if it's still hard/ pressurized, that's a tell tale sign of head gaskets??

2006 GMC with 126,xxx miles.
 
Re:

TBItoy said:
The radiator caps are notorious to stick on these. I'd look there first before assuming the worst.

I'll buy one tomorrow and try it for sure. Will a bad cap cause the upper hose to stay hard too I guess?
 
Re: Re:

rpf500 said:
I'll buy one tomorrow and try it for sure. Will a bad cap cause the upper hose to stay hard too I guess?
Not sure about that, mine sticks and won't let air back into the system when it cools off, so the hoses get sucked down flat.

I assume the hose staying hard (pressurized) would be from residual cylinder pressure bleeding into the cooling system after the engine is cut off. In that case, a properly functioning cap (or stuck closed) would hold pressure in the system.

A stuck open cap would let the system boil over/push fluid out

Hope it works out for you, I haven't rallye heard of any common Duramax head gasket problems, except for maybe overboosted/overfueled engines
 
Re: Duramax head gaskets???

You might have just gotten her hot and didnt realize it. I've done that with my 07 f250...pulled off on an exit and noticed a wet wheel well...but i knew id been hard on it just before taking the exit.
 
Re: Re:

TBItoy said:
I haven't rallye heard of any common Duramax head gasket problems, except for maybe overboosted/overfueled engines

05/06 LLY trucks have an issue with Head gaskets.

Do you know if you have an early or late model 06? in late 06 they changed to LBZ motor which usually didnt have that issue.
 
Re: Duramax head gaskets???

I thought 04.5-05 were lly motors and all 06-07.5 were lbz. Lb7 and lly have bad head gasket designs from the factory and are notorious for going out especially running hotter tunes. Lbz rarely have gasket problems unless your always running a hot tune and beating the piss out of it. I have a 06 and I was losing coolant. It was from a block off plate that served absolutely no purpose and the gasket went bad. It's right above the bell housing on the passenger side and is an absolute bitch to get too.
 
Re: Duramax head gaskets???

What was the build date on your truck? Early production LBZ's had the gen1 style crimped design head gaskets. The engine assembly plant switched to the new gen2 riveted style HG's sometime in December of 05 to fix gasket failures popping up in LLY and early LBZ trucks. I have 195k on my LBZ with no issues but my build date is July of 06 so my motor should have the newer style gaskets.

A friend of mine had to change the HG's on his 05 lly earlier this year. He had the same symptoms you're experiencing, truck ran fine under normal conditions but under load when towing he'd start blowing coolant out of the overflow bypass tube. This all happened shortly after bumping up his PPE tune to level 3. Basically combustion pressure was getting by the gaskets and pressurizing the coolant system causing it to blow fluid out of the bypass tube. He ordered ARP studs and the new riveted style gaskets from Merchant Auto (I believe) and all has been good since.
 
Re: Duramax head gaskets???

Jacksonwolf39 said:
I thought 04.5-05 were lly motors and all 06-07.5 were lbz. Lb7 and lly have bad head gasket designs from the factory and are notorious for going out especially running hotter tunes. Lbz rarely have gasket problems unless your always running a hot tune and beating the piss out of it. I have a 06 and I was losing coolant. It was from a block off plate that served absolutely no purpose and the gasket went bad. It's right above the bell housing on the passenger side and is an absolute bitch to get too.

Nah like Chevota said the early 06 trucks were LLYs also.
 
Re: Duramax head gaskets???

Ok, I wasn't sure so that's good to know. But I had a lly blew a HG at 150k running edge programmer, put the new style riveted HG in it and while your in there May as well throw some arp head studs in there as other have said. I ran mine till 200k and sold it with no problems.
 
Re: Duramax head gaskets???

Thanks for all the replies. I don't know build date but I will know when I get home tonight and look. Tallnate is correct, 12/5/05 is the date they switched to the new gaskets from what I have found. I know from the VIN that I do not have the LBZ, but I do have an 06, with a 6 speed.

I did pick up a cap today and will try it tonight. When I checked this AM, the hose was not that hard to squeeze. But, when I took off the radiator cap there was a small hiss that came out. No fluid, just air pressure. So, I am trying to hold out hope that the cap is in fact bad and not letting off pressure at the correct rate, thus causing the issue I had.

For those that have done this or known someone who has, what kind of time are we talking here? I have read various things on line some saying as much as 37 hours of labor and shops charging upwards of 5k!! I guess the method you use to clean the block is critical as well as having the heads reworked while they are off. I prefer to do this myself but the more I read, the more I wonder what the hell I'll be getting in to. A/C and transmissions, I take for repair, the rest I do at home. This one has me worried though.
 
Re: Duramax head gaskets???

Drove around last night for a bit and came home and parked it. Went out this morning, hose was not hard, but not really soft either. Slowly loosened radiator cap and heard a small hiss. No fluid loss, but it burped a little.

So from what I can tell, I'm going to have to put head gaskets on this truck. I'm going to try and drive it a little more over the weekend and see what it does but I'm thinking I'm screwed.
 
Re: Duramax head gaskets???

Since you have already changed the cap drive to operating temp then park for 1 hour go back check upper hose after an hour if hose has pressure on it more then likely it is head gaskets another check you can do if you know someone with a pressure tester hook it up and let the truck idle make sure to do it while the engine is cold because heat can cause a leak to slow or dissappear if you build up pressure at an idle before the truck has Reached operating temp then it is a headgasket
 
Re: Duramax head gaskets???

Well unfortunately with that build date you do have the old style gaskets. Do you see any black sooty particles floating around inside the fluid chamber. When my friends lly started purging fluid we noticed this.. basically black exhaust particles seeping by the gaskets and getting into the coolant system.

As far as the time involved in the replacement, it's every bit of 40+ hours for a 1st timer. We started out pulling everything off with the motor still in the truck but if I remember correctly there wasn't going to be enough room between the firewall and the rear of the engine to drop the studs in so the whole engine came out and was reassembled on the floor. Definitely have the heads checked and cleaned at a reputable shop. Prepping the block before reassembly is important too. You'll want an overhead creeper for sure, they are a lifesaver in projects like this. There's also a flywheel key tool you need to buy to lock the flywheel so that you can break the harmonic balancer nut without rotating the crank. It inserts through a slot on the driver side of the allison. I'd go ahead and change the water pump too while it's out and easy to access. Merchant sells the upgraded replacement pump with the impeller tig welded to the shaft.

There's several really good HG swap posts out there. Just do a lot of research first so that you know what you're getting into and if it's something you're willing to tackle. If you want, PM me your email address and I'll send you some info I found before we started on my friends project.
 
Re: Duramax head gaskets???

Thanks for the info Tyler and Nate. There are no particles in the tank that I can see and no bubbles while the truck is running either.

I'll do a compression test just to be 100% sure, but I am already confident that it's the gasket.

I'm probably going to let this job go to a shop. I read some posts about doing it and I just do not have the motivation for it. Maybe it's the cold weather or maybe it's the memories of doing this 2 winters ago on my other truck with a 454 and that being a bitch. Visually, this one looks 10 times harder and from what I am reading, it is.

One other question....Am I good to drive this thing a distance? I have no shops in my area that I'd let do this job. I want it to go to a diesel shop once I find one. I assume I can still drive the truck there, maybe just take it easy? No coolant is getting in the oil like you'd usually see so that is good I guess.
 
Re: Duramax head gaskets???

rpf500 said:
Thanks for the info Tyler and Nate. There are no particles in the tank that I can see and no bubbles while the truck is running either.

I'll do a compression test just to be 100% sure, but I am already confident that it's the gasket.

I'm probably going to let this job go to a shop. I read some posts about doing it and I just do not have the motivation for it. Maybe it's the cold weather or maybe it's the memories of doing this 2 winters ago on my other truck with a 454 and that being a bitch. Visually, this one looks 10 times harder and from what I am reading, it is.

One other question....Am I good to drive this thing a distance? I have no shops in my area that I'd let do this job. I want it to go to a diesel shop once I find one. I assume I can still drive the truck there, maybe just take it easy? No coolant is getting in the oil like you'd usually see so that is good I guess.

Told ya to go with an 8.1 :stir:

I wouldn't even worry with it if it is that small... I wonder if GM cooling tabs work magic on a dmax like they do on a Northstar?
 
Re: Duramax head gaskets???

muddinmetal said:
Told ya to go with an 8.1 :stir:

I wouldn't even worry with it if it is that small... I wonder if GM cooling tabs work magic on a dmax like they do on a Northstar?

I was wondering where the hell you were at and when you would post something!! I would have went 8.1 if there were not IMPOSSIBLE to find in a white crew cab and not a ragged out base model.

I really like this truck and I am glad I got it. I wish this would have occurred before the exhaust, leveling kit, and 6 brand new 285 tires I just put on it. :wtflol:
 

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