05 lly coolant question--yes I have searched. Lol

DAKOTAKIDD

Member
Sep 26, 2014
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8
Hey all...Like the title says I have a 05 LLY Coolant question. A little history: I previously had a 03 LB7 and just after I got it, I had to do all the injectors and head gaskets and replace one head. Ouch--Welcome to the diesel world..lol In august, I had a accident in that truck towing my travel trailer and it was a total loss. So with the insurance money, I went and bought a 05 LLY CCSB. It has a intake, 4" exhaust and S&B turbo mouth piece. It came with a bully dog programmer that the previous owner didn't use.So he says..The PO to him did use it. I have no idea on what setting. Just before I bought the truck, he had most of the fluids changed and coolant change was one of them. Because of my past history with the LB7, I kept an eye on the coolant level and before I bought it I had it sent to the dealer for a full inspection, injector balance rate check (all well within spec and asked them to check to see if the head gaskets were gone via a coolant system pressure test. Not sure of the name, they called it but all came back ok.

So I bought the truck. Drove it around for a couple weeks keeping an eye on everything including coolant level and all was well. First trip (400km/250mi) mostly uphill mountain passes etc with 2 quads loaded on the sled deck and a full utility trailer. Got to the destination, checked the coolant the next am and it was an inch or so below the full cold line. (I had it topped off to the full cold line prior). I also noticed the coolant temp would fluctuate between 185 and 210 depending if i was onto the fuel or not uphill 65-70 miles per hour. I kinda blamed the coolant drop on air pocket from the PO's coolant change So I topped it off to the line a headed home. When I got back all was well. No drop in coolant.

So this past weekend, I drove another 500km/333mi with no load, just bags in the box in mountain passes again with consistent speeds of 75 mph. Next am I check the level and its down a little bit, but down none the less. Drove around the town I was in and this am I checked it again and it even lower. I will check it again tomorrow am and but I no its gonna be low. I have not topped it off yet. Temps today would go below 185 on down hills at 75 MPH?? Normal?? When this happened, outside temps were near freezing. As soon as I was into the pedal again up it would go to 185??? Upper rad hose is still soft in the am. Checked the H2O pump weep hole area and it dry. No puddles on the ground. I looked all over the engine from above and below and can see nothing. Occasionally I can smell the good ol sweet smell of the dexcool under the hood when I walk around it after driving it. Seems to be more in the front centre of the engine but I can't isolate anything. No white smoke while driving but a little puff on start occasionally. Not very often.

So here is my question, I am hoping its not the head gaskets on the way out like my old LB7 (fingers crossed and taped). Water pump looks dry around weep hole. What else can I check? I am a newb to the LLY but I know its similar to the LB7 except for injector cups (LB7) and now the LLY has the EGR system that still intact. Is it still burping air from the coolant change? Should I bring the truck into a very reputable diesel shop and have them test the head gaskets? I called before and they say they have a sure fire way of detecting bad gaskets via a laptop somehow looking for pressure spikes etc. while plumbing into the system some how. I have searched and searched with no luck on my specific problems. I have not tried bleeding the coolant system yet. Heat does not disappear in the cab at all.

Any suggestion would be awesome


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02greysixer

Active member
Jun 4, 2011
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North Central FL
Maybe try a new cap? For what it's worth I've never seen an 01-06 Duramax that will maintain coolant at the full cold mark. It always settles out to about the seam in the tank
 

MACKIN

Smell My Finger...
Aug 14, 2006
3,948
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Connecticut
What they could do is check for CO-2 gasses in the coolant and check to see if the coolant system is pressurizing. It might also be possible that they can introduce a dye into the coolant and then check for external leaks with a black light that you cannot see say up in the valley.

Hos much in actual quantity are you losing in miles driven as in a pint quart ?

That temp swing in my opinion isnt that bad considering your climbing as well as towing a load
 
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DAKOTAKIDD

Member
Sep 26, 2014
59
4
8
Maybe try a new cap? For what it's worth I've never seen an 01-06 Duramax that will maintain coolant at the full cold mark. It always settles out to about the seam in the tank


After I did the gasket on my lb7. The coolant stayed at the line. Maybe the lly is different.

I will look into a new cap

Thx


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DAKOTAKIDD

Member
Sep 26, 2014
59
4
8
What they could do is check for CO-2 gasses in the coolant and check to see if the coolant system is pressurizing. It might also be possible that they can introduce a dye into the coolant and then check for external leaks with a black light that you cannot see say up in the valley.

Hos much in actual quantity are you losing in miles driven as in a pint quart ?

That temp swing in my opinion isnt that bad considering your climbing as well as towing a load


Thx for the reply. I will add that to the list for the shop to trouble shoot

As for an amount of coolant. An inch below the line isn't much but I never took an actual measurement. I will from now on.


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