head gasket questions

[lb7lbz]

cralwed under the o1 dmax last night to check why my block heater wasnt working and discovered pass. side head gasket leaking at back corner:(.my question is just how hard are they to do? i have a little experience working on this engine(waterpump) and consider myself to be an average mechanic. do i need any special tools? how much are the parts? should i do anything else while its apart? its an 01 with 214000 and it runs well. just trying to figure out if i can do this one myself or if i have to hire it out. any help from anyone who has every done these would be appreciated thanx:D

[Mark Rinker]

Requires pulling the engine, or removing front clip and raising cab leaving the engine in place.

Either way, there is ALOT of labor involved to get to the problem.

Never heard of one leaking coolant externally due to head gaskets. Usually they pressurize the cooling system and puke coolant out the overflow bottle - especially in cold conditions where both thermostats close while attempting to maintain internal engine coolant temps. Seems like the 2001s were more prone to this problem than any other year. I had one go as well...

I'd make sure you aren't seeing coolant migrating from somewhere else like a heater line fitting. It would really suck to tear this down only to find that the gaskets aren't leaking...

[lb7lbz]

i'll look at it again tonight. ihad had just started it let it run for 2 min. then shut it off yes its cold her 10 below last night so i didnt look 2 long but it looked like head gasket 2 me .can the engine be pulled without pulling off the front clip?

[Duramaster]

:)I have replaced the head gaskets for external leaks. Head gasket leaks are more common on the earlier models. There has been a gasket update. The new gaskets are riveted together. The old ones were crimped. You do not have to remove the front clip for head gaskets. You do not have to remove the engine either. You do need a 12 point 12 mm 3/8 drive shallow socket for removing the turbo exhaust inlet bolts at the exhaust manifolds. You will also need a 17mm 12 point 1/2 inch drive shallow socket for the head bolts. There are three grades of gasket for the right and left ( right/ left and three different thicknesses). There is a tool for pulling the injectors which is a must especially if the injectors have been in place for a long time. Another thing is this engine is held together with Allen screws/ bolts all over the place (5mm, 8mm). Of course you will also need 7, 8, 10, 12, 13, 14, 15mm sockets. I'm sure there are a few more things you will need. Patience is a must. If you lived closer, I would offer to do the job for you at a reasonable rate! Good luck. If you have questions, ask away. :)

[Mark Rinker]

Thanks, Duramaster. How many total hours of labor would you estimate for a typical, skilled and equipped enthusiast that hasn't done this before?

Guess my dealership was setting me up for the big bill when they told me of the engine removal/front clip method. I ended up selling the truck 'as-is' so never had the leak fixed. Never heard from them that you could do this over the fenders.

Also, if you have an external leak as described here, measured in drops, what would the effects be of continuing to operate the truck and add more coolant as needed?

I bet it leaks worse on really cold days. In the summer - it might not leak at all.

[OC_DMAX]

Do you need to remove the turbo charger to pull the heads or can you leave it in place?

[Duramaster]

GM Service Information says to remove the turbocharger for the LB7 application. I have never removed the turbo for the headgasket replacement on the LB7. GM WARRANTY FLAT RATE is 23.9 hours!!! Keep in mind that warranty times are not what the REAL flat rate manuals say it takes to perform the repair. We do not have Chilton flat rate manuals (that is another story). My guess is a shop would quote 28 hours. As far as driving with an external leak goes............. How bad and how fast is the leak? If it's leaking externally, how soon until it leaks internally? :confused:

[lb7lbz]

well guys crawled under the truck again last night(only 5 below last night) and it is the head gasket for sure:(.the truck goes through about a half gallon every 2/3 months. just how bad is it to drive this truck,and when i say drive i mean towing 6000 pounds. also when it does start to lesk internally how bad is that. duramaster you have given me a lot of hope when i hear the engine dosnt have to come out,if i can do this myself it will save me a lot of $$$$$.its nice to have you guys:D

[Mark Rinker]

If it were me, I'd continue to monitor and drive in this cold weather.

I am certain that cold weather compounds the problem - regardless if the leak is into the cooling system or coolant outside the engine. Any time both thermostats are closed when the system is pressurized, the leak will be exaggerated.

If it starts making white exhaust smoke, or dilluting the oil, I'd park it until fixed. GM has a test where they pull all the glowplugs and put white paper in front of the holes, crank the engine over with no fueling (not sure how you do this) and observe the paper to see if there is coolant in the cylinders.

My guess is that you'd have to do that with a warm engine and both thermostats closed to see this one leak - and even then, it would probably be on the floor, not on the paper.

[lb7lbz]

that is basically what i am doing, however i know there will come a time when this needs to be done, so the more info. i can get on this the better. there is never any antifreeze on the ground, dosnt leak fast enough so i assume it burns off on the head.thanks to both rinker and duramaster for your info.oh yeah duramaster if there are any more specialty tools u can think of that i wiil need it would be appreciated i am going to start getting everything ready but hope to not have to do the job untill springtime. thanx again everyone:D

[madmatt]

Keep driving it but regular oil sampling would let you know if it gets worse and starts to leak internally long before you noticed milky oil and risk extensive engine damage.

[Duramaster]

You will also need the tool used for pulling and reseating the injector sleeves. Do you want the Kent-Moore part numbers for these tools? ;)

[lb7lbz]

that would be great duramaster thanks. i assume the heads need to go the machine shop to be checked, is this what u guys do? i wish i was closer too it would be nice to have someone i trust that could do the job at a reasonable rate,as i cant afford to pay a garage 2 grand in labor thanks again

[madmatt]

yeah I take'em and have them cleaned, pressure tested and checked for flatness and have the face resurfaced if needed.

[Duramaster]

Resurfacing of the heads is NOT recommended. Here is some text from SI.



Clean the cylinder head of all foreign material. Do not use a motorized wire brush on any gasket sealing surface.
Clean the threaded holes.
Clean the injector bores using EN-47909 .
Inspect the cylinder head for the following:
• Damage to the gasket surfaces

• Damage to the threaded bolt holes

• Cracks in the exhaust ports

• External cracks in the water chamber

• Cracks between the valve seats

• Restrictions in the intake or exhaust passages

• Restrictions in the cooling system passages

• Rusted, damaged or leaking core plugs

Measure the cylinder head for warpage with a straight edge and a feeler gauge. A cylinder head block deck with warpage in excess of 0.075 mm (0.0030 in) within a 516.5 mm (20.33 in) area must be replaced.


Measure the cylinder head exhaust manifold deck for warpage. A cylinder head exhaust manifold deck with warpage in excess of 0.1 mm (0.0039 in) within a 453 mm (17.83 in) area must be replaced.


Measure the cylinder head intake manifold deck for warpage. A cylinder head intake manifold deck with warpage in excess of 0.3 mm (0.011 in) within a 493 mm (19.41 in) area must be replaced.
:)

[madmatt]

may not be recommended by GM but if it's out of warranty and the only option is buying new heads,, I'd do it. I have and so have many others done it successfully. Ask All the guys w/ built engines and most are running milled heads w/ no problems. Call SoCal Diesel and ask what they do to their heads. I'd also stud'em down while they were off but if not be sure to use the revised torque spec and not the original 01 spec and be sure to use new bolts.

[madmatt]

this is from SoCal's site,,,,

LB7, LLY, LBZ and LMM CNC Ported Cylinder Heads.

These are CNC Ported in house using the latest in simultaneous 5 axis Cad/Cam technology on our own equipment. We have over 24 years of cylinder head manufacturing and porting experience and have worked with many of the top teams in Nascar and NHRA.

Stage 1

(For the budget conscious racer)

• Send us your complete cylinder heads and we will perform the following and reassemble with your valves.

• Simultaneous 5 axis CNC porting of the valve bowls only and radius of the intake inlet.

• Precision 5 angle valve job. We maintain the factory measurement spec from the deck to the valve.

• 32 New spring cup bases.

• 32 Chrome Moly retainers, specifically made for SoCal Diesel.

• 32 New Beehive "Ovate" wire valve springs. We designed these springs specifically for the performance needs of a Duramax. They are made specifically for SoCal Diesel and are not available from anyone else.

• 32 New Valve stem seals.

• Prior to assembly the cylinder head deck surface is given a clean up cut to insure flatness.

[Duramaster]

Injector puller:::::::::::: J 44639, Injector sleeve puller/ installer:::: J 45910, Valve stem seal installer::::::::: J 44640.

Good luck ;)

[lb7lbz]

thanks for all the info guys, for now i am going to drive it and send out the oil for a analysis. hoping to put it off till may but we'll see how that goes. i'll let u know then.thanks :D

[madmatt]

Good luck!