Another LLY...Another Headgasket or Maybe?.. VIDEOS

BoostnLLY

Member
Jan 4, 2020
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Hey guys,

Truck has just over 200K and after about 500 Miles on the new water pump replacement, cross over pipe, new res. cap, and T stats I developed coolant pushing out of the res at idle. I haven't done any formal testing to check exhaust gasses but has all the symptoms.

Here's some videos for sh*ts and grins

https://www.youtube.com/watch?v=6n46I4ZaMYE&feature=youtu.be

https://www.youtube.com/watch?v=INVlUw7zwjM


EDIT: Truck was known to be overfilled with coolant in the res. but was continuing to leak enough to have loss of heat at idle with continuous coolant pushing from the res.
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(Days Later)

As I'm building my case for the head gasket repair, the truck has me confused slightly.

The day the coolant started pouring out of the overflow noticeably at idle was a day that I did an injector clean (Half gallon of diesel and 16 OZ of AC Delco Upper engine cleaner) and was running it at idle for 1.5 hours. This truck is an 2005 GMC LLY and my understanding is there's no injector cups on this motor.

Here is a video of the truck after a 8 hour day of snow plowing and about 150 Miles. I did not observe any coolant coming out of the res. at all yesterday. Zero low coolant lights. I did not run the truck hard at all. I think what i have is a very small head gasket issue/Weak head studs? I believe when the truck is ran hard the heads lift more than it does under normal running conditions and compromises the system until its cool again.


Let me know what you think

https://www.youtube.com/watch?v=aYK1enmHuAI&feature=youtu.be
 
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