Chevy and GMC Duramax Diesel Forum banner
  • Hey Everyone! Enter your ride HERE to be a part of this months Ride of the Month Challenge!

1 - 17 of 17 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 ·
alright so ive been reading threads all day and havent found 1 that really takes it home for me i have a 2005 lly with 200k on it. i recently had it serviced and flushed of all fluids. i now have a low coolant light that constantly comes on. i seem to always have constant pressure even when my truck sits over night. i just replaced the cap a few days ago on the tank to try to solve that with no success. also my coolant tank seems to be draining to about half full or less ive tired burping the system which seemed to help at first because i got heat quicker but the coolant light came back on and the tank was low again. i put a bottle on the overflow to see if i was losing any there but the bottle was empty. ive tried all i can think of so far any suggestions?
 

·
Registered
Joined
·
794 Posts
Possibly head gasket(s). Could also be a lifted injector cup but I'm not sure if your LLY has injector cups designed like an LB7.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #3 ·
im not really sure either i read alot of threads saying head gasket but im holding out for the best on that
 

·
Premium Member
Joined
·
17,806 Posts
The LB7 is the only Duramax with injector cups-!

If the upper radiator hose if firm, after driving and sitting overnight, that is one sign of bad head gaskets.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #5 ·
well i know its not firm i can squeeze it together so theres still hope also when you burp these this should it be running or off i dont seem to get a constant stream either way
 

·
Registered
Joined
·
794 Posts
The LB7 is the only Duramax with injector cups-!

If the upper radiator hose if firm, after driving and sitting overnight, that is one sign of bad head gaskets.
I wasn't sure about injector cups....learn something everyday. I'm very familiar with the LB7 and only slightly familiar with later models.
 

·
Registered
Joined
·
7,904 Posts
Hopefully yours comes out better then mine...it has an apiontment to go in for hg and some other upgrades.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #8 ·
i think i finally got it after driving it in 3rd gear for a while to get the temp up and the thermostat open to force all the air out. i finally got a good stream coming out of the bleeder and my coolant level back to normal ill keep checking during the week and update
 

·
Registered
Joined
·
807 Posts
Hopefully yours comes out better then mine...it has an apiontment to go in for hg and some other upgrades.
What upgrades are you planning while she is under the knife?
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #10 ·
well today after my shift at work i checked under the hood to find that my upper radiator hose was pretty firm and the tank had pressure in it. also the bottle that i hooked up to the hose to collect the overflow was full any other ideas? im beginning to fear for my head gaskets
 

·
Premium Member
Joined
·
17,806 Posts
If you have the firm hose, and pressure in the degasser bottle, then most likely---- head gaskets--!
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #12 ·
whats the easiest way to confirm a blown head gasket?
 

·
Premium Member
Joined
·
17,806 Posts
The coolant dye test, nor the compression test, usually do not work well on the Duramax to check for head gaskets. BUT the firm hose, and pressure in the tank has never failed and there have been hundreds of similar cases posted.

Most everyone is in "Headgasket Denial" mode-!

I replaced my headgaskets several years ago, as "Preventive Maintenance" and just so I could sleep better.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #14 ·
whats a run of the mill gasket job cost compared to an upgrade (whatever that includes). i can do the work myself im pretty good with a wrench and by brother is a diesel mechanic so i think we can handle it.
 

·
Registered
Joined
·
7,904 Posts
What upgrades are you planning while she is under the knife?
Arp head studs, Lml drivers side manifold, MagnaFlow downpipe, Profab Egr delete w/supported riser cap, S&b cai, Merchant auto welded h20 pump, new Bosch fpr.
 

·
Registered
Joined
·
28 Posts
what was the fial problem
The final problem was likely head gaskets.
I had identical symptoms. Replaced both thermostats, replaced the coolant recovery tank cap, and finally topped it off and ran with the cap open - found bubbles rising to the top every thirty seconds or so. This all points to a small head gasket leak; just enough to push air into the coolant, but not enough to allow backflow of coolant into the oil. If you get this, fix ASAP to avoid coolant in your oil, because that leak will only get worse.
I'll hopefully have mine finished up tomorrow.
 
1 - 17 of 17 Posts
Top