Head gasket leak???

[chessy56]

2001 LB7 with 333,338 miles. While doing a front end lube I noticed I've got some wetness near the #1 cylinder (front of engine, passenger's side). There's a streak of orange and dark (oil) mix seeping from what appears to be the mating surface between the head and the block. A check of my oil and coolant bottle shows that I was down a little on both- about a pint or so, which I added. I see a little smoke from the tail pipe when cold, but it smells more like diesel- so, I suspect I've got an injector or two that is staring to degrade. My initial plan is to take it to the dealership in the morning to confirm my suspicions, but perhaps some of the experts on this page can confirm my findings. The engine runs quiet, the oil is dirty (it's due for its periodic change) but I'm not seeing any foam in the oil. The engine surges a bit at idle when it's up to temperature, but my guess is that it's the FP regulator.

Head gasket going? If so, can anyone drop me a ballpark estimate on getting it replaced at the dealership? I wouldn't mind attempting this myself (can do with a good manual and any specialty tools required), but after reading some of the threads on this site I'm beginning to wonder if I'd be better off having a professional pound this out? Would the dealership have to pull the cab in order to do this or can this be done under the hood? Are replacement head studs really $800 for a set (or is that for both heads)? I'd rather have just the one side done now, as I'm still contemplating upgrading to a newer DMax (undecided). The driver's side appears dry/clean and I don't pull anything of substantial weight. It sees a lot of highway miles (about 600 a week).

Any comments appreciated!

[DmaxMaverick]

It really should be properly pressure tested, but..... If it's only a slight seepage, I'd be inclined to try the Cadillac pills, first. That's what they were designed to handle.

The $800 stud kit should be for both banks. But, it wouldn't surprise me if they weren't. Shop around, if not.

[rapidoxidationman]

Cadillac tabs and a month to see if they work... but if they don't:

The dealer will soak you for better than $5,000 and won't do nearly the quality of job you can do yourself for half that price.

You can get 90% of the parts you need from Kennedy on this site, including ARP head studs for about $700 (both sides). They cost twice as much as the stretch bolts the dealer will use, but they're better than the stretch bolts and they're reuseable. Removing the heads will likely show plenty of crud built up in the intake manifold and head ports, so this is the time to bring it all to your machine shop and get the heads cleaned, resurfaced (mandatory), valve guide seals replaced, valve seats ground, valves cleaned up, etc. Count on another $700 for that service (that the dealer wouldn't be doing for you) Good time to replace the water pump, especially given the miles.

I found the only really tough part to be removing and installing the intake manifold. The turbo was in the way but didn't need to be removed. The rest of it was just patience and KEEPING THINGS CLEAN CLEAN CLEAN ON REASSEMBLY.

Lots of pictures helped and lots of notes too. I took a couple of hundred (yes, a couple of hundred). Alldata DIY gave me the how to. Count on 50-60 hours if it's your first time in; I think book time is just less than 40.

Oh, and these:


Not just for freelance proctology

[chessy56]

So far, interesting comments. I had the water pump replaced somewhere around 190K, so it might be close to needing a replacement again. The FPR needs to be replaced as well. Being that I put on 600+ miles a week (250 miles one way, twice weekly, every week), I need a reliable ride. I see dollars going out the door on this, and I supposed it would make sense to do it myself. At 50-60 hours for a first time in, that's about 4-5 weeks of down time being that I only have 1.5 days/weekend to work with. That also suggests a need to buy a 2nd ride to get to/from work. Looks like I'm hosed either way and it'll cost more to fix the truck AND buy a second ride. If the dealer does it, at least it'll have some warranty (and they provide a rental car for the week it'll be down- big deal, eh?).

Unfortunately, I don't think the leak is just a "seep"- losing a couple of pint of oil and a pint of coolant (+/-) in 3600 miles seems like a whole bunch, given I usually don't lose any. It's been suggested that I just do the one leaking side to get me by since the ride is only used on the roads without towing any loads beyond an ATV or a duck boat. Maybe this would be a reasonable time to look for either a new truck or a low miles used ride.

Anyone else who's done this swap or have a preference either way? Can the heads be pulled without pulling the cab?

[DmaxMaverick]

You can do the heads without pulling the cab. If I had a proper hoist and a few extra pairs of hands, my opinion may be different.

Much of the job is getting TOO the heads, so doing both at the same time is beneficial, overall. I don't think you can do them in 1.5 days, first time or not. Maybe if you worked around the clock with little rest, but that lends to sloppy work, then you still have to go to work on Monday. It's more time consuming, rather than labor intensive. You will want a hoist for the heads, as there's little room to work with, and you only have 10 knuckles. Studs are different, as you can't lower the head onto pre-installed studs (cab gets in the way), although it can be done a different way. Many competent shops are capable of this job, and significantly less expensive than the dealer, most of the time.

A pint or two loss of coolant or engine oil is not a lot, and within GM spec. 1 qt of oil between changes (7500 miles) is half of what GM allows, normally. It can still vary depending on conditions, use, and brand/grade of oil. If you are loosing 1 pint of coolant in 3600 miles, the "leak" is not significant. A pint in 10 miles may be. If you aren't mixing fluids (coolant in the oil) I'd try the Cadillac pills for that very little bit.

[Kennedy]

The biggest concern that I have is coolant in the oil. Have an analysis done.

The second concern is corrosion/erosion and crystalizing of the coolant. Dex Cool is great in the absence of "air" but let the air interface with it inside an engine and it makes orange candy. It also can pit and corrode metals quite aggressively. What I'm saying is prepare to possibly replace the head casting(s) if they have been like this for too long.

We've been doing the engine out on a stand method for these. I'm not to fond of the cab lift, but we have discussed trying it. We were all geared up to do this last time but the truck in question had a bulkhead tube attaching the cab to a toolbox in the bed. Through this tube ran stereo wiring so there was no way to lift w/o removal.


Studs are mandatory in my opinion. A skim cut of the head surface is also mandatory. We don't use the cheap hecho en Mexico gaskets that GM went to a few years back. We use the newest version of the old style gaskets that GM used to use. The new ones have no "fire ring" in that they expose all the layer ends to the fire. I just don't care for this design and refuse to even try them.

[Kennedy]

duplicate

[More Power]

I'd rather have just the one side done now, as I'm still contemplating upgrading to a newer DMax (undecided). The driver's side appears dry/clean and I don't pull anything of substantial weight. It sees a lot of highway miles (about 600 a week).

Any comments appreciated!

Doing just one side would be my recommendation. Before deciding whether to do it yourself, put the right front frame rail on a jackstand, remove the tire/wheel and then remove the plastic inner wheelhousing. From that vantage point you'll get a better idea what the work will be like, and you'll be able to judge whether a cab lift or engine out strategy is even necessary.

However, if you're considering a trade-up, now's the time. I know some who were facing a 5-6K$ Duramax repair, and decided in the end to just trade up.
Jim

[chessy56]

Well, I opted for the head gasket change and (right/wrong/otherwise), had the local dealership do it. The heads were sent out and surface ground, new valve guides and valve job. I requested new springs, but the shop received the wrong ones. I requested a test of all springs and was later informed that they all met GM specs for force across the compression range (preferred new, but didn't want to piss away another week in a rental). They did pull the cab to work on the engine. Frankly, I needed the truck and, knowing that the newer ones don't get as good of fuel mileage as my LB7, I opted to keep it for a few more miles. Being a GM employee, the dealership cut me a few price breaks and kept the cost to nearly $5K even. And they popped for a week's rental car as well. I suppose I could've done worse and had I attempted this myself, I'd be parsing this work out over roughly 5 weekends (that's the only time I can get to work on it). That, and either renting a ride for 5 weeks or buying a beater as a second ride (with registration/insurance/yada, yada). Gotta hand it to the dealership as they worked late and early hours to get this thing done for me in a week's time. The original gaskets showed a oil & coolant leak exiting the outer seam near the #1 cylinder- not in danger of anything getting into that cylinder. However, additional wear was observed near the #7 cylinder which was due to fail soon. Dealership would've saved me ~$1200 if I had them only do the right side only, so I set screw it- do both. Hope the SOB lasts for a few thousand more miles until I decide on what I want to do.