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2013 Chevy Silverado 2500hd LML 6.6
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Discussion Starter · #1 ·
Has anyone else out there with an LML had an issue with their coolant reservoir? For whatever reason my truck keeps drinking coolant and I can’t find a leak. I always have a consistent amount of coolant in it that sits just below the minimum line so it’s not eating coolant or burning it. It has no excessive pressure in the lines either so I know that it’s not head gasket related. The weird part is that it constantly sits at that level and when I fill it there are no obvious leaks and the coolant seems to disappear and go right back to that level just below minimum. I’ve heard from diesel shops around here that the reservoirs tend to be faulty in those LMLs but I don’t want to just throw a new reservoir at it for $250 if I don’t have to. If anybody has had a somewhat similar issue to this then please let me know what was going on and the solution.
 

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I had a bad reservoir. The dealer tested it for me and it held pressure just fine. My problem was the overflow side of the tank was leaking so when coolant would be pushed over there it would leak out and there would be nothing to go back to the pressure side when the truck cooled off. I bought a Wherli tank and the problem was solved and it looked damn good. Lol. Replace the tank. You can find them online for about 150.00.
 

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Many have replaced leaking the coolant reservoir.

However, it the level is staying the same, I wouldn't mess with it.

When the engine is cold, one chamber about full and the other empty is normal.
 

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2013 Chevy Silverado 2500hd LML 6.6
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Discussion Starter · #4 ·
Many have replaced leaking the coolant reservoir.

However, it the level is staying the same, I wouldn't mess with it.

When the engine is cold, one chamber about full and the other empty is normal.

The coolant reservoir is not about full tho is the thing. It’s throwing the coolant low message on my dash because it’s halfway between empty and the minimum line. I misspoke a little in my original post.I’ve been told by a few shops that if it’s not budging I shouldn’t worry about it. So that’s a common answer so far
 

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Right before I sold my 2012, I installed another new coolant reservoir. I got the replacement part from GM and it had a leak in the bottom of the overflow side. I called the dealer and told them about it so they ordered another one. Went back the next day and got it, installed it and the 2nd new one had a leak in the same place.

If you can find a good aftermarket product, I'd get it.
 

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Just for giggles, won't cost a dime, is to remove your reservoir cap when its cold, and wash it with hot soapy water, dry then reinstall. Who knows? Dexcool is pretty sticky and can gum up the cap at times, usually making the top hose go flat till it warms up.
 

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2013 Chevy Silverado 2500hd LML 6.6
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Discussion Starter · #7 ·
I had a bad reservoir. The dealer tested it for me and it held pressure just fine. My problem was the overflow side of the tank was leaking so when coolant would be pushed over there it would leak out and there would be nothing to go back to the pressure side when the truck cooled off. I bought a Wherli tank and the problem was solved and it looked damn good. Lol. Replace the tank. You can find them online for about 150.00.
Yea this right here sounds eerily similar to what’s going on with mine. Just can’t seem to pin point a leak anywhere tho. I’ll definitely look into some aftermarket ones. Appreciate the reply
 

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2013 Chevy Silverado 2500hd LML 6.6
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Discussion Starter · #8 ·
Just for giggles, won't cost a dime, is to remove your reservoir cap when its cold, and wash it with hot soapy water, dry then reinstall. Who knows? Dexcool is pretty sticky and can gum up the cap at times, usually making the top hose go flat till it warms up.
hmmm interesting. Might as well try it. Thanks for the response
 

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RD, that was exactly what mine was doing. The pressure side never went empty, just low. That’s because the pressure was never enough to empty the pressure side, just make it low. The dealership also tested my cap and it was good as well. I’d replace your tank.
 

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2022 Silverado 2500, well hopefully soon
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Another possibility is the hose/clamp on the bottom outlet to the engine. It is easiest to see if you remove the air intake. My friend had the same issue, even had the tank and cap replaced and it kept doing it. We tore it apart and found a small amount of coolant below the hose clamp. I happened to have gates heat shrink hose clamps for another project. We took the hose off, cut the end back about a 1/4 inch and installed the heat shrink hose clamp (This was the first time we had ever used them and love them now). It solved his problem.
 

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The coolant reservoir is not about full tho is the thing. It’s throwing the coolant low message on my dash because it’s halfway between empty and the minimum line. I misspoke a little in my original post.I’ve been told by a few shops that if it’s not budging I shouldn’t worry about it. So that’s a common answer so far
It it always leaks down to the sensor, and doesn't go further, I'd be changing the tank.
 
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