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Discussion Starter · #1 ·
I've had problems with having to refill my coolant reservoir tank a handful of times now after a few days or week. The issue at hand is that once the coolant runs out to a certain point on the tank where you can barely see it right above the hoses, it will remain there and never go any lower. The truck has never ran hot,...always runs right under 200. Its making me think there may be a small crack somewhere in the tank just leaking out enough to make me refill it that slowly. Or if it were a bigger problem, a head gasket...but i really am having a hard time believing thats it since it never runs over a certain temp. and no white smoke/blow-by or anything. Any help or ideas would be much appreciated, would like to have this problem fixed and solved so i can flush all water out and put antifreeze in before winter rolls around in a few months. Thanks.
 

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Look at your lower radiator hose. There could be a pinhole leak that doesn't allow it to hit the ground. I just had my water pump leak and it got replaced under warranty. It was leaking out of the weep hole. If it is leaking out anywhere, there will a build-up of antifreeze where it is leaking. You just need to take a look around and see if you find anything.
 

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Discussion Starter · #3 ·
Well see thats the deal, is after it reaches a certain point in the tank it will not lower anymore which is making me think it is the tank, just didnt' know if anyone else had any insight if this was an irregularity or anything. I guess i'll probably just end up takin the tank out and seein if it leaks anywhere.
 

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If it were the tank, you should see some antifreeze build-up on the fenderliner. I am betting it is either the hose or a waterpump. My theory behind that is once your cooling system can't build enough pressure it won't leak anymore. Kinda like when the cap is loose it shouldn't leak any out. There is enough airspace in the tank once it gets down to a certain point that it doesn't force out the coolant. If it is leaking from somewhere, there will be residue from the coolant even if it doesn't reach the ground.
 

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Discussion Starter · #5 ·
Alright,... so how detailed is a waterpump removal and install, other than havin to bust the harmonic balancer off from what i hear....? B/c i'll be doin it soon
 

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Discussion Starter · #6 ·
And another question,...if it were to be a head gasket or injector sleeve issue so that it would cause white exhaust moke, being such a small "leak",..how much white smoke could i expect to see at an idle rev?
 

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I e-mailed instructions on how to change the water pump to you. If it were a head gasket problem, your coolant tank would have almost instant pressure on it after you start the engine. I think the injector cups would leak coolant into the oil. from what I have read on other forums, if the injector cups or injectors go bad you will just about smoke out a parking lot.
 

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I e-mailed instructions on how to change the water pump to you. If it were a head gasket problem, your coolant tank would have almost instant pressure on it after you start the engine. I think the injector cups would leak coolant into the oil. from what I have read on other forums, if the injector cups or injectors go bad you will just about smoke out a parking lot.
I'm about to replace my water pump. Could you send me those instructions too?
 

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I have a leak too it looks like it's coming from the water pump as well. Is your lby water pump instructions the same for a lly if so could you send them to me?
 

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Not for the faint of heart for sure!!!!:rof:rof
 

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I have had GM diesels for over 30 years. The key word was "problems" with all of them. My LB7 with 158K has had 4 sets of injectors, 2 high pressure injection pumps, 2 fuel filter mounts (cracked), 1 hydro boost hose, leaking trans inter cooler coupling, 1 alternator, 1 starter, 1 water pump, head gaskets both sides, 1 A/C compressor (bad clutch) 3 complete sets of idlers, drive shaft center bearing, 3 sets of brakes. It started doing the "low coolant" in the expansion tank trick about 1,000 miles back. The LB7 has a nasty trick with the injector tube seals leaking small amounts of coolant into the engine. GM did have problems with defective coolant tanks. A pressure check quickly revels that with a coolant trickle out the cracked area almost immediately. The injector tube problem is more subtle. Bring the coolant level up to the full mark cold. Remove the glow plugs. If you fail to you will have a hydraulic lock when you try to start the engine. Then your in real trouble, the glow plug getting hit with coolant can be disastrous. Pressurizer the cooling system and leave it for the night. Check the pressure on the gauge and check for any loss of coolant. Even if the gauge had barely dropped in pressure or you can see almost no loss of coolant, the fall in pressure is a clue. With the glow plugs out turn the engine over at least one full revolution. A very good chance you will see coolant come out one of the glow plug holes. 99.9% of the time your injector lock tight sealant has failed. Continued operation of the engine and the coolant loss will increase. When you least expect it crack goes a head, or catastrophic failure of the engine will occur. Our other LB7 with 127K has a little better track record. Our 2006 LLY is a little bit better. Electronic problem with the fuel system seem to be common with all three of them.
We run a fleet of 60 series power Peterbuilts inter cooler problems and some electronic problems with all of them. Mechanically they have turned a million miles with no engine failures or problems. Tear down at 1 mil miles finds no real sleeve, piston, rod or main wear, the engine mics out as in spec. For the med duty trucks we are presently trying the Hino/Toytas, the Duramax just don't seem to be an engine yet. We still have a stack of 6.5 blown engines in the pile next to our shop. That choice was a disaster for us.
 
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