LBZ: Coolant Leak

[coldLBZ]

My truck is leaking coolant. It looks like it's coming from above the back of the starter. It's dripping off where the bellhousing meets the back of the motor and has formed a bit of a puddle. This must have just started in the last couple of days. The tab on the back of the headgasket looks dry, but I can't see good enough back there to tell where it's coming from. The top of the motor is dry and so are the connections at the firewall. Any ideas? Thanks for the help.

 

[LBZ]

Could be the cover on the top of the rear cover. It is just a plate with a gasket. As long as your sure the valley is dry the only other thing it could be is a headgasket or the coolant line for the turbo which is under it and tough to spot.

 

[JD4440]

That's how I noticed my headgasket starting. Is the upper hose pressurized in the morning/ cold ?

 

[coldLBZ]

Thanks for the ideas, I'll check it out more in the daylight.

 

[jraymer]

I know you said the top was dry but I would look at the coolant line for the turbo too, where the hard line turns to rubber line for a bit. The clamps corrode and start to leak. At least thats what happened to mine, it's wet where the intake manifold and valve cover bolt to the head and the coolant runs down the back of the block/trans, pretty much right under your egr.

 

[coldLBZ]

Is the turbo drain a small 90* rubber hose that runs from the driver's side to the front of the motor? It's sitting right next to the fuel rail on the pass side. If so it's dry, and I climbed under the hood and the valley looks dry.
The back of the motor where the pass side head meets the block looks and feels dry back there also. I gave the rad hose a squeeze after the truck was shut off for a bit. It was a bit firm, but still easy to squeeze. Is the upper rad hose rock hard usually if there is a head gasket issue?
Dale, that plate that you're talking about. Is it right above the back of the starter with two bolts holding it on? Kind of facing the pass side, and hidden behind the down pipe and up pipe? I can feel coolant right below the bottom bolt of what I think is that plate. The top of the plate looks dry.
Sorry for the long post.

 

[RENODMAX]

Is the turbo drain a small 90* rubber hose that runs from the driver's side to the front of the motor? It's sitting right next to the fuel rail on the pass side. If so it's dry, and I climbed under the hood and the valley looks dry.
The back of the motor where the pass side head meets the block looks and feels dry back there also. I gave the rad hose a squeeze after the truck was shut off for a bit. It was a bit firm, but still easy to squeeze. Is the upper rad hose rock hard usually if there is a head gasket issue?
Dale, that plate that you're talking about. Is it right above the back of the starter with two bolts holding it on? Kind of facing the pass side, and hidden behind the down pipe and up pipe? I can feel coolant right below the bottom bolt of what I think is that plate. The top of the plate looks dry.
Sorry for the long post.

Check the hoses coming from your egr as well if you still have it. If not check the hose that you used to bypass it going into the heater core through the firewall.

 

[coldLBZ]

EGR has been gone for a while, and the bypass hose is dry.

 

[Josh2002cc]

That's how I noticed my headgasket starting. Is the upper hose pressurized in the morning/ cold ?

YEP!!! This is the same problem mine had! Bad news but hey....it is what it is. Good luck.

 

[blk smoke lb7]

I just had that plate leaking on mine,what a pain with the motor in the truck and rdl uppipes and manifolds hard to get to without removing either the uppipe or the manifold

 

[ruffmanatv]

Pull the inner fender out on the passenger side and look at the front of the head too. I found that mine was leaking worse there than at the back.

 

[coldLBZ]

I pulled the inner fender out and took a look around. It looks dry all around the head gasket. I cleaned up all of the coolant to get a better idea of where it's leaking and I think it's that plate since the bottom of that plate was wet again after driving about 30 miles. Does anyone know the part number for that gasket? Looks like the up-pipe/downpipe may have to come out to fix this. And I assume the coolant will have to be drained as well. Are there drains anywhere? Thanks.

 

[JD4440]

there's a drain on each side of the block. They're painted yellow.

 

[coldLBZ]

After some searching I found: Rear adapter housing water cover gasket P/N 97229043. Does this sound right?

 

[coldLBZ]

Bump
Well I have the gasket, and it's looking like I will have to fix this sooner than later. It's dumping coolant every time I shut the truck off now. So a couple of questions: Will I have to remove the downpipe and the pass side up pipe? Looks like I will. And as for refilling the coolant, do I just refill through the overflow? Do I have to crack anything to bleed air out of the system? Thanks. Now to see if I can borrow some shop space somewhere as it's about -10C right now.

 

[Josh2002cc]

As to refilling the coolant, fill through the overflow and run the truck long enough to circulate through the system then check and add as needed. That's the easy part.

 

[GeorgiaDieselGTO]

I believe you will need to remove the downpipe, just wiggle it up out of your way you wont need to take it clear out. Had it happen to my truck. i just used sealant on it

 

[JoshH]

There is a bolt on top of the thermostat housing that is used to bleed most of the air out of the system.