LBZ: Weird Coolant Issue??

[Murracha]

I installed an EGR blocker plate and now I am noticing coolant issues. First thing I saw was my upper radiator hose was collapsed. From what ive read that's just a bad coolant cap. Now I noticed a small coolant leak from sitting overnight. Checked the upper radiator hose in the morning before starting the truck and it was hard (Head Gasket), and also coolant reservoir was low. My temp does not fluctuate and I have hot heat. I topped off the coolant and continued to drive with no issues. Checked the upper radiator hose again the next morning and it was fine. Symptoms are come and go. There is pressure in the coolant tank as well. I did not reroute the coolant after blocking the EGR. Looks like coolant is possibly leaking from a hose that goes into the firewall, but leaking from the front of the motor. Any ideas on the issue before I dump time and money into anything?? I have a hard time believing its a HG but still concerned about the issue.

 

[MadMax17]

Sorry to tell you but this is exactly how I found mine leaking recently. I started having small coolant leaks at night and still had pressure in the system in the morning. It wasn't everynight, but several times a week it would happen. My egr has had a blocker plate for 20,000 miles but I never deleted the cooler from the cooling sytem. I hoped it was boost pressure entering the system, I bypassed the cooler and drove it hard, the next morning I felt the hose and it was soft so I thought I was good. Drove the truck to flagstaff (3hrs) for the weekend and had the coolant leak and hard hose again. I pulled it down and found #6 leaking by the exhuast valve - right where the drivers side manifold kinks down.
Check your trucks build date too, they changed gasket design in december 2005, the new gaskets don't have as much problem. Mine was built 11/05 of course and had the older gaskets. Try bypassing the cooler first before diving in to HG's. I hope your luck is better than mine.

 

[NC-smokinlmm]

Sounds like the water pump and the heater core connection at the firewall are leaking. Both common problems in a duramax. Fix those issues first then go forward from there...

 

[Murracha]

Thanks for the info guys. How do i go about checking the build date? Really hope its not HG. I still have a loan lol i cant afford that! If it is whats an average price to have someone else do just HG not head studs?